Some fixes and bunch of object_id conversions

index 14435ab65d..0913f8ab86 100644
@@ -915,6 +915,10 @@ static struct remote_lock *lock_remote(const char *path, long timeout)
 				lock->timeout = -1;
 			}
 			XML_ParserFree(parser);
+		} else {
+			fprintf(stderr,
+				"error: curl result=%d, HTTP code=%ld\n",
+				results.curl_result, results.http_code);
 		}
 	} else {
 		fprintf(stderr, "Unable to start LOCK request\n");

index 2893f3c103..2ad656c1be 100644
@@ -232,7 +232,7 @@ static struct commit *fake_working_tree_commit(struct diff_options *opt,
 	convert_to_git(&the_index, path, buf.buf, buf.len, &buf, 0);
 	origin->file.ptr = buf.buf;
 	origin->file.size = buf.len;
-	pretend_sha1_file(buf.buf, buf.len, OBJ_BLOB, origin->blob_oid.hash);
+	pretend_sha1_file(buf.buf, buf.len, OBJ_BLOB, &origin->blob_oid);
 
 	/*
 	 * Read the current index, replace the path entry with

index d8b975a571..8ed75d7260 100644
@@ -1241,7 +1241,8 @@ extern int sha1_object_info(const unsigned char *, unsigned long *);
 extern int hash_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1);
 extern int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *return_sha1);
 extern int hash_sha1_file_literally(const void *buf, unsigned long len, const char *type, struct object_id *oid, unsigned flags);
-extern int pretend_sha1_file(void *, unsigned long, enum object_type, unsigned char *);
+extern int pretend_sha1_file(void *, unsigned long, enum object_type,
+			     struct object_id *oid);
 extern int force_object_loose(const unsigned char *sha1, time_t mtime);
 extern int git_open_cloexec(const char *name, int flags);
 #define git_open(name) git_open_cloexec(name, O_RDONLY)

index 3da70ac650..dc8adb9d17 100644
@@ -1313,12 +1313,12 @@ static void *read_object(const unsigned char *sha1, enum object_type *type,
 }
 
 int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
-		      unsigned char *sha1)
+		      struct object_id *oid)
 {
 	struct cached_object *co;
 
-	hash_sha1_file(buf, len, typename(type), sha1);
-	if (has_sha1_file(sha1) || find_cached_object(sha1))
+	hash_sha1_file(buf, len, typename(type), oid->hash);
+	if (has_sha1_file(oid->hash) || find_cached_object(oid->hash))
 		return 0;
 	ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);
 	co = &cached_objects[cached_object_nr++];

@@ -1326,7 +1326,7 @@ int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
 	co->type = type;
 	co->buf = xmalloc(len);
 	memcpy(co->buf, buf, len);
-	hashcpy(co->sha1, sha1);
+	hashcpy(co->sha1, oid->hash);
 	return 0;
 }
 

index 8ed75d7260..04af1d69e4 100644
@@ -1047,8 +1047,6 @@ extern const struct object_id empty_tree_oid;
 	"\xe6\x9d\xe2\x9b\xb2\xd1\xd6\x43\x4b\x8b" \
 	"\x29\xae\x77\x5a\xd8\xc2\xe4\x8c\x53\x91"
 extern const struct object_id empty_blob_oid;
-#define EMPTY_BLOB_SHA1_BIN (empty_blob_oid.hash)
-
 
 static inline int is_empty_blob_sha1(const unsigned char *sha1)
 {

index 7c4b45e30e..effa531d35 100644
@@ -253,7 +253,7 @@ static int do_read_blob(const struct object_id *oid,
 
 	if (sha1_stat) {
 		memset(&sha1_stat->stat, 0, sizeof(sha1_stat->stat));
-		hashcpy(sha1_stat->sha1, oid->hash);
+		oidcpy(&sha1_stat->oid, oid);
 	}
 
 	if (sz == 0) {

@@ -823,7 +823,7 @@ static int add_excludes(const char *fname, const char *base, int baselen,
 		if (size == 0) {
 			if (sha1_stat) {
 				fill_stat_data(&sha1_stat->stat, &st);
-				hashcpy(sha1_stat->sha1, EMPTY_BLOB_SHA1_BIN);
+				oidcpy(&sha1_stat->oid, &empty_blob_oid);
 				sha1_stat->valid = 1;
 			}
 			close(fd);

@@ -847,10 +847,11 @@ static int add_excludes(const char *fname, const char *base, int baselen,
 				 !ce_stage(istate->cache[pos]) &&
 				 ce_uptodate(istate->cache[pos]) &&
 				 !would_convert_to_git(istate, fname))
-				hashcpy(sha1_stat->sha1,
-					istate->cache[pos]->oid.hash);
+				oidcpy(&sha1_stat->oid,
+				       &istate->cache[pos]->oid);
 			else
-				hash_sha1_file(buf, size, "blob", sha1_stat->sha1);
+				hash_sha1_file(buf, size, "blob",
+					       sha1_stat->oid.hash);
 			fill_stat_data(&sha1_stat->stat, &st);
 			sha1_stat->valid = 1;
 		}

@@ -1223,7 +1224,7 @@ static void prep_exclude(struct dir_struct *dir,
 		}
 
 		/* Try to read per-directory file */
-		hashclr(sha1_stat.sha1);
+		oidclr(&sha1_stat.oid);
 		sha1_stat.valid = 0;
 		if (dir->exclude_per_dir &&
 		    /*

@@ -1269,9 +1270,9 @@ static void prep_exclude(struct dir_struct *dir,
 		 * order, though, if you do that.
 		 */
 		if (untracked &&
-		    hashcmp(sha1_stat.sha1, untracked->exclude_sha1)) {
+		    hashcmp(sha1_stat.oid.hash, untracked->exclude_sha1)) {
 			invalidate_gitignore(dir->untracked, untracked);
-			hashcpy(untracked->exclude_sha1, sha1_stat.sha1);
+			hashcpy(untracked->exclude_sha1, sha1_stat.oid.hash);
 		}
 		dir->exclude_stack = stk;
 		current = stk->baselen;

@@ -2228,13 +2229,13 @@ static struct untracked_cache_dir *validate_untracked_cache(struct dir_struct *d
 
 	/* Validate $GIT_DIR/info/exclude and core.excludesfile */
 	root = dir->untracked->root;
-	if (hashcmp(dir->ss_info_exclude.sha1,
-		    dir->untracked->ss_info_exclude.sha1)) {
+	if (oidcmp(&dir->ss_info_exclude.oid,
+		   &dir->untracked->ss_info_exclude.oid)) {
 		invalidate_gitignore(dir->untracked, root);
 		dir->untracked->ss_info_exclude = dir->ss_info_exclude;
 	}
-	if (hashcmp(dir->ss_excludes_file.sha1,
-		    dir->untracked->ss_excludes_file.sha1)) {
+	if (oidcmp(&dir->ss_excludes_file.oid,
+		   &dir->untracked->ss_excludes_file.oid)) {
 		invalidate_gitignore(dir->untracked, root);
 		dir->untracked->ss_excludes_file = dir->ss_excludes_file;
 	}

@@ -2638,8 +2639,8 @@ void write_untracked_extension(struct strbuf *out, struct untracked_cache *untra
 	FLEX_ALLOC_MEM(ouc, exclude_per_dir, untracked->exclude_per_dir, len);
 	stat_data_to_disk(&ouc->info_exclude_stat, &untracked->ss_info_exclude.stat);
 	stat_data_to_disk(&ouc->excludes_file_stat, &untracked->ss_excludes_file.stat);
-	hashcpy(ouc->info_exclude_sha1, untracked->ss_info_exclude.sha1);
-	hashcpy(ouc->excludes_file_sha1, untracked->ss_excludes_file.sha1);
+	hashcpy(ouc->info_exclude_sha1, untracked->ss_info_exclude.oid.hash);
+	hashcpy(ouc->excludes_file_sha1, untracked->ss_excludes_file.oid.hash);
 	ouc->dir_flags = htonl(untracked->dir_flags);
 
 	varint_len = encode_varint(untracked->ident.len, varbuf);

@@ -2821,7 +2822,7 @@ static void load_sha1_stat(struct sha1_stat *sha1_stat,
 			   const unsigned char *sha1)
 {
 	stat_data_from_disk(&sha1_stat->stat, data);
-	hashcpy(sha1_stat->sha1, sha1);
+	hashcpy(sha1_stat->oid.hash, sha1);
 	sha1_stat->valid = 1;
 }
 

index 11a047ba48..afbff73357 100644
@@ -76,7 +76,7 @@ struct exclude_list_group {
 
 struct sha1_stat {
 	struct stat_data stat;
-	unsigned char sha1[20];
+	struct object_id oid;
 	int valid;
 };
 

index f752532ffb..d7c55c2355 100644
@@ -54,8 +54,8 @@ int cmd_main(int ac, const char **av)
 		printf("no untracked cache\n");
 		return 0;
 	}
-	printf("info/exclude %s\n", sha1_to_hex(uc->ss_info_exclude.sha1));
-	printf("core.excludesfile %s\n", sha1_to_hex(uc->ss_excludes_file.sha1));
+	printf("info/exclude %s\n", oid_to_hex(&uc->ss_info_exclude.oid));
+	printf("core.excludesfile %s\n", oid_to_hex(&uc->ss_excludes_file.oid));
 	printf("exclude_per_dir %s\n", uc->exclude_per_dir);
 	printf("flags %08x\n", uc->dir_flags);
 	if (uc->root)

index 321a9fa68d..d6cbb4dc66 100644
@@ -3154,7 +3154,7 @@ static int apply_binary(struct apply_state *state,
 		 * See if the old one matches what the patch
 		 * applies to.
 		 */
-		hash_sha1_file(img->buf, img->len, blob_type, oid.hash);
+		hash_sha1_file(img->buf, img->len, blob_type, &oid);
 		if (strcmp(oid_to_hex(&oid), patch->old_sha1_prefix))
 			return error(_("the patch applies to '%s' (%s), "
 				       "which does not match the "

@@ -3199,7 +3199,7 @@ static int apply_binary(struct apply_state *state,
 				     name);
 
 		/* verify that the result matches */
-		hash_sha1_file(img->buf, img->len, blob_type, oid.hash);
+		hash_sha1_file(img->buf, img->len, blob_type, &oid);
 		if (strcmp(oid_to_hex(&oid), patch->new_sha1_prefix))
 			return error(_("binary patch to '%s' creates incorrect result (expecting %s, got %s)"),
 				name, patch->new_sha1_prefix, oid_to_hex(&oid));

index 4c51aec81f..f7c69008f1 100644
@@ -959,8 +959,7 @@ static void resolve_delta(struct object_entry *delta_obj,
 	if (!result->data)
 		bad_object(delta_obj->idx.offset, _("failed to apply delta"));
 	hash_sha1_file(result->data, result->size,
-		       typename(delta_obj->real_type),
-		       delta_obj->idx.oid.hash);
+		       typename(delta_obj->real_type), &delta_obj->idx.oid);
 	sha1_object(result->data, NULL, result->size, delta_obj->real_type,
 		    &delta_obj->idx.oid);
 	counter_lock();

index 10078ae371..7267d06b17 100644
@@ -355,7 +355,7 @@ static void check_one_mergetag(struct commit *commit,
 	struct tag *tag;
 	int i;
 
-	hash_sha1_file(extra->value, extra->len, typename(OBJ_TAG), tag_oid.hash);
+	hash_sha1_file(extra->value, extra->len, typename(OBJ_TAG), &tag_oid);
 	tag = lookup_tag(&tag_oid);
 	if (!tag)
 		die(_("bad mergetag in commit '%s'"), ref);

index 62ea264c46..2e494e2a4b 100644
@@ -258,7 +258,7 @@ static void write_object(unsigned nr, enum object_type type,
 	} else {
 		struct object *obj;
 		int eaten;
-		hash_sha1_file(buf, size, typename(type), obj_list[nr].oid.hash);
+		hash_sha1_file(buf, size, typename(type), &obj_list[nr].oid);
 		added_object(nr, type, buf, size);
 		obj = parse_object_buffer(&obj_list[nr].oid, type, size, buf,
 					  &eaten);

index e03e72c34a..0df09180ee 100644
@@ -400,15 +400,14 @@ static int update_one(struct cache_tree *it,
 	}
 
 	if (repair) {
-		unsigned char sha1[20];
-		hash_sha1_file(buffer.buf, buffer.len, tree_type, sha1);
-		if (has_sha1_file(sha1))
-			hashcpy(it->oid.hash, sha1);
+		struct object_id oid;
+		hash_sha1_file(buffer.buf, buffer.len, tree_type, &oid);
+		if (has_sha1_file(oid.hash))
+			oidcpy(&it->oid, &oid);
 		else
 			to_invalidate = 1;
 	} else if (dryrun)
-		hash_sha1_file(buffer.buf, buffer.len, tree_type,
-			       it->oid.hash);
+		hash_sha1_file(buffer.buf, buffer.len, tree_type, &it->oid);
 	else if (write_sha1_file(buffer.buf, buffer.len, tree_type, it->oid.hash)) {
 		strbuf_release(&buffer);
 		return -1;

index 04af1d69e4..b953d9f82c 100644
@@ -1236,7 +1236,8 @@ static inline const unsigned char *lookup_replace_object(const unsigned char *sh
 
 /* Read and unpack a sha1 file into memory, write memory to a sha1 file */
 extern int sha1_object_info(const unsigned char *, unsigned long *);
-extern int hash_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1);
+extern int hash_sha1_file(const void *buf, unsigned long len, const char *type,
+			  struct object_id *oid);
 extern int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *return_sha1);
 extern int hash_sha1_file_literally(const void *buf, unsigned long len, const char *type, struct object_id *oid, unsigned flags);
 extern int pretend_sha1_file(void *, unsigned long, enum object_type,

index 1a41a48e15..999bcb1336 100644
@@ -898,7 +898,7 @@ static int ident_to_git(const char *path, const char *src, size_t len,
 static int ident_to_worktree(const char *path, const char *src, size_t len,
                              struct strbuf *buf, int ident)
 {
-	unsigned char sha1[20];
+	struct object_id oid;
 	char *to_free = NULL, *dollar, *spc;
 	int cnt;
 

@@ -912,7 +912,7 @@ static int ident_to_worktree(const char *path, const char *src, size_t len,
 	/* are we "faking" in place editing ? */
 	if (src == buf->buf)
 		to_free = strbuf_detach(buf, NULL);
-	hash_sha1_file(src, len, "blob", sha1);
+	hash_sha1_file(src, len, "blob", &oid);
 
 	strbuf_grow(buf, len + cnt * 43);
 	for (;;) {

@@ -969,7 +969,7 @@ static int ident_to_worktree(const char *path, const char *src, size_t len,
 
 		/* step 4: substitute */
 		strbuf_addstr(buf, "Id: ");
-		strbuf_add(buf, sha1_to_hex(sha1), 40);
+		strbuf_add(buf, sha1_to_hex(oid.hash), GIT_SHA1_HEXSZ);
 		strbuf_addstr(buf, " $");
 	}
 	strbuf_add(buf, src, len);

index 245e999fe5..93cbcb9de4 100644
@@ -261,7 +261,7 @@ static unsigned int hash_filespec(struct diff_filespec *filespec)
 		if (diff_populate_filespec(filespec, 0))
 			return 0;
 		hash_sha1_file(filespec->data, filespec->size, "blob",
-			       filespec->oid.hash);
+			       &filespec->oid);
 	}
 	return sha1hash(filespec->oid.hash);
 }

index effa531d35..a3454d6cd0 100644
@@ -851,7 +851,7 @@ static int add_excludes(const char *fname, const char *base, int baselen,
 				       &istate->cache[pos]->oid);
 			else
 				hash_sha1_file(buf, size, "blob",
-					       sha1_stat->oid.hash);
+					       &sha1_stat->oid);
 			fill_stat_data(&sha1_stat->stat, &st);
 			sha1_stat->valid = 1;
 		}

index fca29d4799..019026e1ae 100644
@@ -499,7 +499,7 @@ static void show_one_mergetag(struct commit *commit,
 	int status, nth;
 	size_t payload_size, gpg_message_offset;
 
-	hash_sha1_file(extra->value, extra->len, typename(OBJ_TAG), oid.hash);
+	hash_sha1_file(extra->value, extra->len, typename(OBJ_TAG), &oid);
 	tag = lookup_tag(&oid);
 	if (!tag)
 		return; /* error message already given */

index dc8adb9d17..88b960316c 100644
@@ -788,7 +788,7 @@ void *xmmap(void *start, size_t length,
 int check_sha1_signature(const unsigned char *sha1, void *map,
 			 unsigned long size, const char *type)
 {
-	unsigned char real_sha1[20];
+	struct object_id real_oid;
 	enum object_type obj_type;
 	struct git_istream *st;
 	git_SHA_CTX c;

@@ -796,8 +796,8 @@ int check_sha1_signature(const unsigned char *sha1, void *map,
 	int hdrlen;
 
 	if (map) {
-		hash_sha1_file(map, size, type, real_sha1);
-		return hashcmp(sha1, real_sha1) ? -1 : 0;
+		hash_sha1_file(map, size, type, &real_oid);
+		return hashcmp(sha1, real_oid.hash) ? -1 : 0;
 	}
 
 	st = open_istream(sha1, &obj_type, &size, NULL);

@@ -822,9 +822,9 @@ int check_sha1_signature(const unsigned char *sha1, void *map,
 			break;
 		git_SHA1_Update(&c, buf, readlen);
 	}
-	git_SHA1_Final(real_sha1, &c);
+	git_SHA1_Final(real_oid.hash, &c);
 	close_istream(st);
-	return hashcmp(sha1, real_sha1) ? -1 : 0;
+	return hashcmp(sha1, real_oid.hash) ? -1 : 0;
 }
 
 int git_open_cloexec(const char *name, int flags)

@@ -1317,7 +1317,7 @@ int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
 {
 	struct cached_object *co;
 
-	hash_sha1_file(buf, len, typename(type), oid->hash);
+	hash_sha1_file(buf, len, typename(type), oid);
 	if (has_sha1_file(oid->hash) || find_cached_object(oid->hash))
 		return 0;
 	ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);

@@ -1486,11 +1486,11 @@ static int write_buffer(int fd, const void *buf, size_t len)
 }
 
 int hash_sha1_file(const void *buf, unsigned long len, const char *type,
-                   unsigned char *sha1)
+		   struct object_id *oid)
 {
 	char hdr[32];
 	int hdrlen = sizeof(hdr);
-	write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
+	write_sha1_file_prepare(buf, len, type, oid->hash, hdr, &hdrlen);
 	return 0;
 }
 

@@ -1769,7 +1769,7 @@ static int index_mem(struct object_id *oid, void *buf, size_t size,
 	if (write_object)
 		ret = write_sha1_file(buf, size, typename(type), oid->hash);
 	else
-		ret = hash_sha1_file(buf, size, typename(type), oid->hash);
+		ret = hash_sha1_file(buf, size, typename(type), oid);
 	if (re_allocated)
 		free(buf);
 	return ret;

@@ -1793,7 +1793,7 @@ static int index_stream_convert_blob(struct object_id *oid, int fd,
 				      oid->hash);
 	else
 		ret = hash_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
-				     oid->hash);
+				     oid);
 	strbuf_release(&sbuf);
 	return ret;
 }

@@ -1907,7 +1907,7 @@ int index_path(struct object_id *oid, const char *path, struct stat *st, unsigne
 		if (strbuf_readlink(&sb, path, st->st_size))
 			return error_errno("readlink(\"%s\")", path);
 		if (!(flags & HASH_WRITE_OBJECT))
-			hash_sha1_file(sb.buf, sb.len, blob_type, oid->hash);
+			hash_sha1_file(sb.buf, sb.len, blob_type, oid);
 		else if (write_sha1_file(sb.buf, sb.len, blob_type, oid->hash))
 			rc = error("%s: failed to insert into database", path);
 		strbuf_release(&sb);

index b953d9f82c..cf98573805 100644
@@ -1029,7 +1029,7 @@ static inline void hashclr(unsigned char *hash)
 
 static inline void oidclr(struct object_id *oid)
 {
-	hashclr(oid->hash);
+	memset(oid->hash, 0, GIT_MAX_RAWSZ);
 }
 
 

index 396b7338df..0f899a7212 100644
@@ -161,19 +161,17 @@ static void match_trees(const struct object_id *hash1,
  * A tree "hash1" has a subdirectory at "prefix".  Come up with a
  * tree object by replacing it with another tree "hash2".
  */
-static int splice_tree(const unsigned char *hash1,
-		       const char *prefix,
-		       const unsigned char *hash2,
-		       unsigned char *result)
+static int splice_tree(const struct object_id *hash1, const char *prefix,
+		       const struct object_id *hash2, struct object_id *result)
 {
 	char *subpath;
 	int toplen;
 	char *buf;
 	unsigned long sz;
 	struct tree_desc desc;
-	unsigned char *rewrite_here;
-	const unsigned char *rewrite_with;
-	unsigned char subtree[20];
+	struct object_id *rewrite_here;
+	const struct object_id *rewrite_with;
+	struct object_id subtree;
 	enum object_type type;
 	int status;
 

@@ -182,9 +180,9 @@ static int splice_tree(const unsigned char *hash1,
 	if (*subpath)
 		subpath++;
 
-	buf = read_sha1_file(hash1, &type, &sz);
+	buf = read_sha1_file(hash1->hash, &type, &sz);
 	if (!buf)
-		die("cannot read tree %s", sha1_to_hex(hash1));
+		die("cannot read tree %s", oid_to_hex(hash1));
 	init_tree_desc(&desc, buf, sz);
 
 	rewrite_here = NULL;

@@ -197,26 +195,26 @@ static int splice_tree(const unsigned char *hash1,
 		if (strlen(name) == toplen &&
 		    !memcmp(name, prefix, toplen)) {
 			if (!S_ISDIR(mode))
-				die("entry %s in tree %s is not a tree",
-				    name, sha1_to_hex(hash1));
-			rewrite_here = (unsigned char *) oid->hash;
+				die("entry %s in tree %s is not a tree", name,
+				    oid_to_hex(hash1));
+			rewrite_here = (struct object_id *)oid;
 			break;
 		}
 		update_tree_entry(&desc);
 	}
 	if (!rewrite_here)
-		die("entry %.*s not found in tree %s",
-		    toplen, prefix, sha1_to_hex(hash1));
+		die("entry %.*s not found in tree %s", toplen, prefix,
+		    oid_to_hex(hash1));
 	if (*subpath) {
-		status = splice_tree(rewrite_here, subpath, hash2, subtree);
+		status = splice_tree(rewrite_here, subpath, hash2, &subtree);
 		if (status)
 			return status;
-		rewrite_with = subtree;
-	}
-	else
+		rewrite_with = &subtree;
+	} else {
 		rewrite_with = hash2;
-	hashcpy(rewrite_here, rewrite_with);
-	status = write_sha1_file(buf, sz, tree_type, result);
+	}
+	oidcpy(rewrite_here, rewrite_with);
+	status = write_sha1_file(buf, sz, tree_type, result->hash);
 	free(buf);
 	return status;
 }

@@ -280,7 +278,7 @@ void shift_tree(const struct object_id *hash1,
 	if (!*add_prefix)
 		return;
 
-	splice_tree(hash1->hash, add_prefix, hash2->hash, shifted->hash);
+	splice_tree(hash1, add_prefix, hash2, shifted);
 }
 
 /*

@@ -334,7 +332,7 @@ void shift_tree_by(const struct object_id *hash1,
 		 * shift tree2 down by adding shift_prefix above it
 		 * to match tree1.
 		 */
-		splice_tree(hash1->hash, shift_prefix, hash2->hash, shifted->hash);
+		splice_tree(hash1, shift_prefix, hash2, shifted);
 	else
 		/*
 		 * shift tree2 up by removing shift_prefix from it

index acfe9d3c8c..6e6abb05cd 100644
@@ -1641,8 +1641,8 @@ static void do_commit(const struct am_state *state)
 		setenv("GIT_COMMITTER_DATE",
 			state->ignore_date ? "" : state->author_date, 1);
 
-	if (commit_tree(state->msg, state->msg_len, tree.hash, parents, commit.hash,
-				author, state->sign_commit))
+	if (commit_tree(state->msg, state->msg_len, &tree, parents, &commit,
+			author, state->sign_commit))
 		die(_("failed to write commit object"));
 
 	reflog_msg = getenv("GIT_REFLOG_ACTION");

index 2177251e24..e5bdf57b1e 100644
@@ -117,8 +117,8 @@ int cmd_commit_tree(int argc, const char **argv, const char *prefix)
 			die_errno("git commit-tree: failed to read");
 	}
 
-	if (commit_tree(buffer.buf, buffer.len, tree_oid.hash, parents,
-			commit_oid.hash, NULL, sign_commit)) {
+	if (commit_tree(buffer.buf, buffer.len, &tree_oid, parents, &commit_oid,
+			NULL, sign_commit)) {
 		strbuf_release(&buffer);
 		return 1;
 	}

index 8a87701414..c14878302e 100644
@@ -1792,8 +1792,9 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 		append_merge_tag_headers(parents, &tail);
 	}
 
-	if (commit_tree_extended(sb.buf, sb.len, active_cache_tree->oid.hash,
-			 parents, oid.hash, author_ident.buf, sign_commit, extra)) {
+	if (commit_tree_extended(sb.buf, sb.len, &active_cache_tree->oid,
+				 parents, &oid, author_ident.buf, sign_commit,
+				 extra)) {
 		rollback_index_files();
 		die(_("failed to write commit object"));
 	}

index 30264cfd7c..92ba99a1a5 100644
@@ -820,8 +820,8 @@ static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
 	pptr = commit_list_append(head, pptr);
 	pptr = commit_list_append(remoteheads->item, pptr);
 	prepare_to_commit(remoteheads);
-	if (commit_tree(merge_msg.buf, merge_msg.len, result_tree.hash, parents,
-			result_commit.hash, NULL, sign_commit))
+	if (commit_tree(merge_msg.buf, merge_msg.len, &result_tree, parents,
+			&result_commit, NULL, sign_commit))
 		die(_("failed to write commit object"));
 	finish(head, remoteheads, &result_commit, "In-index merge");
 	drop_save();

@@ -845,8 +845,8 @@ static int finish_automerge(struct commit *head,
 		commit_list_insert(head, &parents);
 	strbuf_addch(&merge_msg, '\n');
 	prepare_to_commit(remoteheads);
-	if (commit_tree(merge_msg.buf, merge_msg.len, result_tree->hash, parents,
-			result_commit.hash, NULL, sign_commit))
+	if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
+			&result_commit, NULL, sign_commit))
 		die(_("failed to write commit object"));
 	strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
 	finish(head, remoteheads, &result_commit, buf.buf);

index cab8d4455b..760137e54b 100644
@@ -1395,9 +1395,8 @@ void free_commit_extra_headers(struct commit_extra_header *extra)
 	}
 }
 
-int commit_tree(const char *msg, size_t msg_len,
-		const unsigned char *tree,
-		struct commit_list *parents, unsigned char *ret,
+int commit_tree(const char *msg, size_t msg_len, const struct object_id *tree,
+		struct commit_list *parents, struct object_id *ret,
 		const char *author, const char *sign_commit)
 {
 	struct commit_extra_header *extra = NULL, **tail = &extra;

@@ -1526,8 +1525,8 @@ N_("Warning: commit message did not conform to UTF-8.\n"
    "variable i18n.commitencoding to the encoding your project uses.\n");
 
 int commit_tree_extended(const char *msg, size_t msg_len,
-			 const unsigned char *tree,
-			 struct commit_list *parents, unsigned char *ret,
+			 const struct object_id *tree,
+			 struct commit_list *parents, struct object_id *ret,
 			 const char *author, const char *sign_commit,
 			 struct commit_extra_header *extra)
 {

@@ -1535,7 +1534,7 @@ int commit_tree_extended(const char *msg, size_t msg_len,
 	int encoding_is_utf8;
 	struct strbuf buffer;
 
-	assert_sha1_type(tree, OBJ_TREE);
+	assert_sha1_type(tree->hash, OBJ_TREE);
 
 	if (memchr(msg, '\0', msg_len))
 		return error("a NUL byte in commit log message not allowed.");

@@ -1544,7 +1543,7 @@ int commit_tree_extended(const char *msg, size_t msg_len,
 	encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
 
 	strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
-	strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
+	strbuf_addf(&buffer, "tree %s\n", oid_to_hex(tree));
 
 	/*
 	 * NOTE! This ordering means that the same exact tree merged with a

@@ -1583,7 +1582,7 @@ int commit_tree_extended(const char *msg, size_t msg_len,
 		goto out;
 	}
 
-	result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
+	result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret->hash);
 out:
 	strbuf_release(&buffer);
 	return result;

index 8c68ca1a5a..5dd9df4448 100644
@@ -263,14 +263,15 @@ extern void append_merge_tag_headers(struct commit_list *parents,
 				     struct commit_extra_header ***tail);
 
 extern int commit_tree(const char *msg, size_t msg_len,
-		       const unsigned char *tree,
-		       struct commit_list *parents, unsigned char *ret,
+		       const struct object_id *tree,
+		       struct commit_list *parents, struct object_id *ret,
 		       const char *author, const char *sign_commit);
 
 extern int commit_tree_extended(const char *msg, size_t msg_len,
-				const unsigned char *tree,
-				struct commit_list *parents, unsigned char *ret,
-				const char *author, const char *sign_commit,
+				const struct object_id *tree,
+				struct commit_list *parents,
+				struct object_id *ret, const char *author,
+				const char *sign_commit,
 				struct commit_extra_header *);
 
 extern struct commit_extra_header *read_commit_extra_headers(struct commit *, const char **);

index 17ee8602b3..d2f87147cc 100644
@@ -56,8 +56,8 @@ int notes_cache_write(struct notes_cache *c)
 
 	if (write_notes_tree(&c->tree, tree_oid.hash))
 		return -1;
-	if (commit_tree(c->validity, strlen(c->validity), tree_oid.hash, NULL,
-			commit_oid.hash, NULL, NULL) < 0)
+	if (commit_tree(c->validity, strlen(c->validity), &tree_oid, NULL,
+			&commit_oid, NULL, NULL) < 0)
 		return -1;
 	if (update_ref("update notes cache", c->tree.update_ref, &commit_oid,
 		       NULL, 0, UPDATE_REFS_QUIET_ON_ERR) < 0)

index 0f6573cb17..c09c5e0e47 100644
@@ -642,9 +642,8 @@ int notes_merge(struct notes_merge_options *o,
 		struct commit_list *parents = NULL;
 		commit_list_insert(remote, &parents); /* LIFO order */
 		commit_list_insert(local, &parents);
-		create_notes_commit(local_tree, parents,
-				    o->commit_msg.buf, o->commit_msg.len,
-				    result_oid->hash);
+		create_notes_commit(local_tree, parents, o->commit_msg.buf,
+				    o->commit_msg.len, result_oid);
 	}
 
 found_result:

@@ -718,8 +717,8 @@ int notes_merge_commit(struct notes_merge_options *o,
 		strbuf_setlen(&path, baselen);
 	}
 
-	create_notes_commit(partial_tree, partial_commit->parents,
-			    msg, strlen(msg), result_oid->hash);
+	create_notes_commit(partial_tree, partial_commit->parents, msg,
+			    strlen(msg), result_oid);
 	unuse_commit_buffer(partial_commit, buffer);
 	if (o->verbosity >= 4)
 		printf("Finalized notes merge commit: %s\n",

index 5c8e70c98f..058c642dac 100644
@@ -6,7 +6,7 @@
 
 void create_notes_commit(struct notes_tree *t, struct commit_list *parents,
 			 const char *msg, size_t msg_len,
-			 unsigned char *result_sha1)
+			 struct object_id *result_oid)
 {
 	struct object_id tree_oid;
 

@@ -27,7 +27,8 @@ void create_notes_commit(struct notes_tree *t, struct commit_list *parents,
 		/* else: t->ref points to nothing, assume root/orphan commit */
 	}
 
-	if (commit_tree(msg, msg_len, tree_oid.hash, parents, result_sha1, NULL, NULL))
+	if (commit_tree(msg, msg_len, &tree_oid, parents, result_oid, NULL,
+			NULL))
 		die("Failed to commit notes tree to database");
 }
 

@@ -47,7 +48,7 @@ void commit_notes(struct notes_tree *t, const char *msg)
 	strbuf_addstr(&buf, msg);
 	strbuf_complete_line(&buf);
 
-	create_notes_commit(t, NULL, buf.buf, buf.len, commit_oid.hash);
+	create_notes_commit(t, NULL, buf.buf, buf.len, &commit_oid);
 	strbuf_insert(&buf, 0, "notes: ", 7); /* commit message starts at index 7 */
 	update_ref(buf.buf, t->update_ref, &commit_oid, NULL, 0,
 		   UPDATE_REFS_DIE_ON_ERR);

index 1190578398..5d79cbef51 100644
@@ -15,7 +15,8 @@
  * The resulting commit SHA1 is stored in result_sha1.
  */
 void create_notes_commit(struct notes_tree *t, struct commit_list *parents,
-			 const char *msg, size_t msg_len, unsigned char *result_sha1);
+			 const char *msg, size_t msg_len,
+			 struct object_id *result_oid);
 
 void commit_notes(struct notes_tree *t, const char *msg);
 

index c7f21fae44..3f4f94507a 100644
@@ -270,8 +270,8 @@ static int note_tree_insert(struct notes_tree *t, struct int_node *tree,
 				if (!oidcmp(&l->val_oid, &entry->val_oid))
 					return 0;
 
-				ret = combine_notes(l->val_oid.hash,
-						    entry->val_oid.hash);
+				ret = combine_notes(&l->val_oid,
+						    &entry->val_oid);
 				if (!ret && is_null_oid(&l->val_oid))
 					note_tree_remove(t, tree, n, entry);
 				free(entry);

@@ -786,8 +786,8 @@ static int prune_notes_helper(const struct object_id *object_oid,
 	return 0;
 }
 
-int combine_notes_concatenate(unsigned char *cur_sha1,
-		const unsigned char *new_sha1)
+int combine_notes_concatenate(struct object_id *cur_oid,
+			      const struct object_id *new_oid)
 {
 	char *cur_msg = NULL, *new_msg = NULL, *buf;
 	unsigned long cur_len, new_len, buf_len;

@@ -795,18 +795,18 @@ int combine_notes_concatenate(unsigned char *cur_sha1,
 	int ret;
 
 	/* read in both note blob objects */
-	if (!is_null_sha1(new_sha1))
-		new_msg = read_sha1_file(new_sha1, &new_type, &new_len);
+	if (!is_null_oid(new_oid))
+		new_msg = read_sha1_file(new_oid->hash, &new_type, &new_len);
 	if (!new_msg || !new_len || new_type != OBJ_BLOB) {
 		free(new_msg);
 		return 0;
 	}
-	if (!is_null_sha1(cur_sha1))
-		cur_msg = read_sha1_file(cur_sha1, &cur_type, &cur_len);
+	if (!is_null_oid(cur_oid))
+		cur_msg = read_sha1_file(cur_oid->hash, &cur_type, &cur_len);
 	if (!cur_msg || !cur_len || cur_type != OBJ_BLOB) {
 		free(cur_msg);
 		free(new_msg);
-		hashcpy(cur_sha1, new_sha1);
+		oidcpy(cur_oid, new_oid);
 		return 0;
 	}
 

@@ -825,20 +825,20 @@ int combine_notes_concatenate(unsigned char *cur_sha1,
 	free(new_msg);
 
 	/* create a new blob object from buf */
-	ret = write_sha1_file(buf, buf_len, blob_type, cur_sha1);
+	ret = write_sha1_file(buf, buf_len, blob_type, cur_oid->hash);
 	free(buf);
 	return ret;
 }
 
-int combine_notes_overwrite(unsigned char *cur_sha1,
-		const unsigned char *new_sha1)
+int combine_notes_overwrite(struct object_id *cur_oid,
+			    const struct object_id *new_oid)
 {
-	hashcpy(cur_sha1, new_sha1);
+	oidcpy(cur_oid, new_oid);
 	return 0;
 }
 
-int combine_notes_ignore(unsigned char *cur_sha1,
-		const unsigned char *new_sha1)
+int combine_notes_ignore(struct object_id *cur_oid,
+			 const struct object_id *new_oid)
 {
 	return 0;
 }

@@ -848,17 +848,17 @@ int combine_notes_ignore(unsigned char *cur_sha1,
  * newlines removed.
  */
 static int string_list_add_note_lines(struct string_list *list,
-				      const unsigned char *sha1)
+				      const struct object_id *oid)
 {
 	char *data;
 	unsigned long len;
 	enum object_type t;
 
-	if (is_null_sha1(sha1))
+	if (is_null_oid(oid))
 		return 0;
 
 	/* read_sha1_file NUL-terminates */
-	data = read_sha1_file(sha1, &t, &len);
+	data = read_sha1_file(oid->hash, &t, &len);
 	if (t != OBJ_BLOB || !data || !len) {
 		free(data);
 		return t != OBJ_BLOB || !data;

@@ -884,17 +884,17 @@ static int string_list_join_lines_helper(struct string_list_item *item,
 	return 0;
 }
 
-int combine_notes_cat_sort_uniq(unsigned char *cur_sha1,
-		const unsigned char *new_sha1)
+int combine_notes_cat_sort_uniq(struct object_id *cur_oid,
+				const struct object_id *new_oid)
 {
 	struct string_list sort_uniq_list = STRING_LIST_INIT_DUP;
 	struct strbuf buf = STRBUF_INIT;
 	int ret = 1;
 
 	/* read both note blob objects into unique_lines */
-	if (string_list_add_note_lines(&sort_uniq_list, cur_sha1))
+	if (string_list_add_note_lines(&sort_uniq_list, cur_oid))
 		goto out;
-	if (string_list_add_note_lines(&sort_uniq_list, new_sha1))
+	if (string_list_add_note_lines(&sort_uniq_list, new_oid))
 		goto out;
 	string_list_remove_empty_items(&sort_uniq_list, 0);
 	string_list_sort(&sort_uniq_list);

@@ -905,7 +905,7 @@ int combine_notes_cat_sort_uniq(unsigned char *cur_sha1,
 				 string_list_join_lines_helper, &buf))
 		goto out;
 
-	ret = write_sha1_file(buf.buf, buf.len, blob_type, cur_sha1);
+	ret = write_sha1_file(buf.buf, buf.len, blob_type, cur_oid->hash);
 
 out:
 	strbuf_release(&buf);

index 3848c2fb3f..88da38b5f4 100644
@@ -9,27 +9,32 @@
  * When adding a new note annotating the same object as an existing note, it is
  * up to the caller to decide how to combine the two notes. The decision is
  * made by passing in a function of the following form. The function accepts
- * two SHA1s -- of the existing note and the new note, respectively. The
+ * two object_ids -- of the existing note and the new note, respectively. The
  * function then combines the notes in whatever way it sees fit, and writes the
- * resulting SHA1 into the first SHA1 argument (cur_sha1). A non-zero return
+ * resulting oid into the first argument (cur_oid). A non-zero return
  * value indicates failure.
  *
- * The two given SHA1s shall both be non-NULL and different from each other.
- * Either of them (but not both) may be == null_sha1, which indicates an
- * empty/non-existent note. If the resulting SHA1 (cur_sha1) is == null_sha1,
+ * The two given object_ids shall both be non-NULL and different from each
+ * other. Either of them (but not both) may be == null_oid, which indicates an
+ * empty/non-existent note. If the resulting oid (cur_oid) is == null_oid,
  * the note will be removed from the notes tree.
  *
  * The default combine_notes function (you get this when passing NULL) is
  * combine_notes_concatenate(), which appends the contents of the new note to
  * the contents of the existing note.
  */
-typedef int (*combine_notes_fn)(unsigned char *cur_sha1, const unsigned char *new_sha1);
+typedef int (*combine_notes_fn)(struct object_id *cur_oid,
+				const struct object_id *new_oid);
 
 /* Common notes combinators */
-int combine_notes_concatenate(unsigned char *cur_sha1, const unsigned char *new_sha1);
-int combine_notes_overwrite(unsigned char *cur_sha1, const unsigned char *new_sha1);
-int combine_notes_ignore(unsigned char *cur_sha1, const unsigned char *new_sha1);
-int combine_notes_cat_sort_uniq(unsigned char *cur_sha1, const unsigned char *new_sha1);
+int combine_notes_concatenate(struct object_id *cur_oid,
+			      const struct object_id *new_oid);
+int combine_notes_overwrite(struct object_id *cur_oid,
+			    const struct object_id *new_oid);
+int combine_notes_ignore(struct object_id *cur_oid,
+			 const struct object_id *new_oid);
+int combine_notes_cat_sort_uniq(struct object_id *cur_oid,
+				const struct object_id *new_oid);
 
 /*
  * Notes tree object

index d2f87147cc..010ad236cb 100644
@@ -54,7 +54,7 @@ int notes_cache_write(struct notes_cache *c)
 	if (!c->tree.dirty)
 		return 0;
 
-	if (write_notes_tree(&c->tree, tree_oid.hash))
+	if (write_notes_tree(&c->tree, &tree_oid))
 		return -1;
 	if (commit_tree(c->validity, strlen(c->validity), &tree_oid, NULL,
 			&commit_oid, NULL, NULL) < 0)

index 058c642dac..02407fe2a7 100644
@@ -12,7 +12,7 @@ void create_notes_commit(struct notes_tree *t, struct commit_list *parents,
 
 	assert(t->initialized);
 
-	if (write_notes_tree(t, tree_oid.hash))
+	if (write_notes_tree(t, &tree_oid))
 		die("Failed to write notes tree to database");
 
 	if (!parents) {

index 3f4f94507a..09ef1ce33a 100644
@@ -1123,11 +1123,12 @@ int for_each_note(struct notes_tree *t, int flags, each_note_fn fn,
 	return for_each_note_helper(t, t->root, 0, 0, flags, fn, cb_data);
 }
 
-int write_notes_tree(struct notes_tree *t, unsigned char *result)
+int write_notes_tree(struct notes_tree *t, struct object_id *result)
 {
 	struct tree_write_stack root;
 	struct write_each_note_data cb_data;
 	int ret;
+	int flags;
 
 	if (!t)
 		t = &default_notes_tree;

@@ -1141,12 +1142,13 @@ int write_notes_tree(struct notes_tree *t, unsigned char *result)
 	cb_data.next_non_note = t->first_non_note;
 
 	/* Write tree objects representing current notes tree */
-	ret = for_each_note(t, FOR_EACH_NOTE_DONT_UNPACK_SUBTREES |
-				FOR_EACH_NOTE_YIELD_SUBTREES,
-			write_each_note, &cb_data) ||
-		write_each_non_note_until(NULL, &cb_data) ||
-		tree_write_stack_finish_subtree(&root) ||
-		write_sha1_file(root.buf.buf, root.buf.len, tree_type, result);
+	flags = FOR_EACH_NOTE_DONT_UNPACK_SUBTREES |
+		FOR_EACH_NOTE_YIELD_SUBTREES;
+	ret = for_each_note(t, flags, write_each_note, &cb_data) ||
+	      write_each_non_note_until(NULL, &cb_data) ||
+	      tree_write_stack_finish_subtree(&root) ||
+	      write_sha1_file(root.buf.buf, root.buf.len, tree_type,
+			      result->hash);
 	strbuf_release(&root.buf);
 	return ret;
 }

index 88da38b5f4..0433f45db5 100644
@@ -217,7 +217,7 @@ int for_each_note(struct notes_tree *t, int flags, each_note_fn fn,
  * Write the given notes_tree structure to the object database
  *
  * Creates a new tree object encapsulating the current state of the given
- * notes_tree, and stores its SHA1 into the 'result' argument.
+ * notes_tree, and stores its object id into the 'result' argument.
  *
  * Returns zero on success, non-zero on failure.
  *

@@ -225,7 +225,7 @@ int for_each_note(struct notes_tree *t, int flags, each_note_fn fn,
  * this function has returned zero. Please also remember to create a
  * corresponding commit object, and update the appropriate notes ref.
  */
-int write_notes_tree(struct notes_tree *t, unsigned char *result);
+int write_notes_tree(struct notes_tree *t, struct object_id *result);
 
 /* Flags controlling the operation of prune */
 #define NOTES_PRUNE_VERBOSE 1

index d6cbb4dc66..4951f8a130 100644
@@ -3554,7 +3554,7 @@ static int try_threeway(struct apply_state *state,
 
 	/* Preimage the patch was prepared for */
 	if (patch->is_new)
-		write_sha1_file("", 0, blob_type, pre_oid.hash);
+		write_sha1_file("", 0, blob_type, &pre_oid);
 	else if (get_oid(patch->old_sha1_prefix, &pre_oid) ||
 		 read_blob_object(&buf, &pre_oid, patch->old_mode))
 		return error(_("repository lacks the necessary blob to fall back on 3-way merge."));

@@ -3570,7 +3570,7 @@ static int try_threeway(struct apply_state *state,
 		return -1;
 	}
 	/* post_oid is theirs */
-	write_sha1_file(tmp_image.buf, tmp_image.len, blob_type, post_oid.hash);
+	write_sha1_file(tmp_image.buf, tmp_image.len, blob_type, &post_oid);
 	clear_image(&tmp_image);
 
 	/* our_oid is ours */

@@ -3583,7 +3583,7 @@ static int try_threeway(struct apply_state *state,
 			return error(_("cannot read the current contents of '%s'"),
 				     patch->old_name);
 	}
-	write_sha1_file(tmp_image.buf, tmp_image.len, blob_type, our_oid.hash);
+	write_sha1_file(tmp_image.buf, tmp_image.len, blob_type, &our_oid);
 	clear_image(&tmp_image);
 
 	/* in-core three-way merge between post and our using pre as base */

@@ -4291,7 +4291,7 @@ static int add_index_file(struct apply_state *state,
 			}
 			fill_stat_cache_info(ce, &st);
 		}
-		if (write_sha1_file(buf, size, blob_type, ce->oid.hash) < 0) {
+		if (write_sha1_file(buf, size, blob_type, &ce->oid) < 0) {
 			free(ce);
 			return error(_("unable to create backing store "
 				       "for newly created file %s"), path);

index 8bdc927d3f..a98e88288e 100644
@@ -227,8 +227,7 @@ static int checkout_merged(int pos, const struct checkout *state)
 	 * (it also writes the merge result to the object database even
 	 * when it may contain conflicts).
 	 */
-	if (write_sha1_file(result_buf.ptr, result_buf.size,
-			    blob_type, oid.hash))
+	if (write_sha1_file(result_buf.ptr, result_buf.size, blob_type, &oid))
 		die(_("Unable to add merge result for '%s'"), path);
 	free(result_buf.ptr);
 	ce = make_cache_entry(mode, oid.hash, path, 2, 0);

index 031b750f06..d4044da3e4 100644
@@ -151,7 +151,7 @@ static int verify_tag(char *buffer, unsigned long size)
 int cmd_mktag(int argc, const char **argv, const char *prefix)
 {
 	struct strbuf buf = STRBUF_INIT;
-	unsigned char result_sha1[20];
+	struct object_id result;
 
 	if (argc != 1)
 		usage("git mktag");

@@ -165,10 +165,10 @@ int cmd_mktag(int argc, const char **argv, const char *prefix)
 	if (verify_tag(buf.buf, buf.len) < 0)
 		die("invalid tag signature file");
 
-	if (write_sha1_file(buf.buf, buf.len, tag_type, result_sha1) < 0)
+	if (write_sha1_file(buf.buf, buf.len, tag_type, &result) < 0)
 		die("unable to write tag file");
 
 	strbuf_release(&buf);
-	printf("%s\n", sha1_to_hex(result_sha1));
+	printf("%s\n", oid_to_hex(&result));
 	return 0;
 }

index da0fd8cd70..1988f5396d 100644
@@ -40,7 +40,7 @@ static int ent_compare(const void *a_, const void *b_)
 				 b->name, b->len, b->mode);
 }
 
-static void write_tree(unsigned char *sha1)
+static void write_tree(struct object_id *oid)
 {
 	struct strbuf buf;
 	size_t size;

@@ -57,7 +57,7 @@ static void write_tree(unsigned char *sha1)
 		strbuf_add(&buf, ent->sha1, 20);
 	}
 
-	write_sha1_file(buf.buf, buf.len, tree_type, sha1);
+	write_sha1_file(buf.buf, buf.len, tree_type, oid);
 	strbuf_release(&buf);
 }
 

@@ -142,7 +142,7 @@ static void mktree_line(char *buf, size_t len, int nul_term_line, int allow_miss
 int cmd_mktree(int ac, const char **av, const char *prefix)
 {
 	struct strbuf sb = STRBUF_INIT;
-	unsigned char sha1[20];
+	struct object_id oid;
 	int nul_term_line = 0;
 	int allow_missing = 0;
 	int is_batch_mode = 0;

@@ -181,8 +181,8 @@ int cmd_mktree(int ac, const char **av, const char *prefix)
 			 */
 			; /* skip creating an empty tree */
 		} else {
-			write_tree(sha1);
-			puts(sha1_to_hex(sha1));
+			write_tree(&oid);
+			puts(oid_to_hex(&oid));
 			fflush(stdout);
 		}
 		used=0; /* reset tree entry buffer for re-use in batch mode */

index 7c81761645..fb1caf6590 100644
@@ -198,9 +198,9 @@ static void prepare_note_data(const struct object_id *object, struct note_data *
 	}
 }
 
-static void write_note_data(struct note_data *d, unsigned char *sha1)
+static void write_note_data(struct note_data *d, struct object_id *oid)
 {
-	if (write_sha1_file(d->buf.buf, d->buf.len, blob_type, sha1)) {
+	if (write_sha1_file(d->buf.buf, d->buf.len, blob_type, oid)) {
 		error(_("unable to write note object"));
 		if (d->edit_path)
 			error(_("the note contents have been left in %s"),

@@ -459,7 +459,7 @@ static int add(int argc, const char **argv, const char *prefix)
 
 	prepare_note_data(&object, &d, note ? note->hash : NULL);
 	if (d.buf.len || allow_empty) {
-		write_note_data(&d, new_note.hash);
+		write_note_data(&d, &new_note);
 		if (add_note(t, &object, &new_note, combine_notes_overwrite))
 			die("BUG: combine_notes_overwrite failed");
 		commit_notes(t, "Notes added by 'git notes add'");

@@ -619,7 +619,7 @@ static int append_edit(int argc, const char **argv, const char *prefix)
 	}
 
 	if (d.buf.len || allow_empty) {
-		write_note_data(&d, new_note.hash);
+		write_note_data(&d, &new_note);
 		if (add_note(t, &object, &new_note, combine_notes_overwrite))
 			die("BUG: combine_notes_overwrite failed");
 		logmsg = xstrfmt("Notes added by 'git notes %s'", argv[0]);

index b7ce7c7f52..dd28d33b30 100644
@@ -69,7 +69,7 @@ static int sent_capabilities;
 static int shallow_update;
 static const char *alt_shallow_file;
 static struct strbuf push_cert = STRBUF_INIT;
-static unsigned char push_cert_sha1[20];
+static struct object_id push_cert_oid;
 static struct signature_check sigcheck;
 static const char *push_cert_nonce;
 static const char *cert_nonce_seed;

@@ -633,8 +633,9 @@ static void prepare_push_cert_sha1(struct child_process *proc)
 		int bogs /* beginning_of_gpg_sig */;
 
 		already_done = 1;
-		if (write_sha1_file(push_cert.buf, push_cert.len, "blob", push_cert_sha1))
-			hashclr(push_cert_sha1);
+		if (write_sha1_file(push_cert.buf, push_cert.len, "blob",
+				    &push_cert_oid))
+			oidclr(&push_cert_oid);
 
 		memset(&sigcheck, '\0', sizeof(sigcheck));
 		sigcheck.result = 'N';

@@ -655,9 +656,9 @@ static void prepare_push_cert_sha1(struct child_process *proc)
 		strbuf_release(&gpg_status);
 		nonce_status = check_nonce(push_cert.buf, bogs);
 	}
-	if (!is_null_sha1(push_cert_sha1)) {
+	if (!is_null_oid(&push_cert_oid)) {
 		argv_array_pushf(&proc->env_array, "GIT_PUSH_CERT=%s",
-				 sha1_to_hex(push_cert_sha1));
+				 oid_to_hex(&push_cert_oid));
 		argv_array_pushf(&proc->env_array, "GIT_PUSH_CERT_SIGNER=%s",
 				 sigcheck.signer ? sigcheck.signer : "");
 		argv_array_pushf(&proc->env_array, "GIT_PUSH_CERT_KEY=%s",

index 7267d06b17..358d7aca28 100644
@@ -410,7 +410,7 @@ static int create_graft(int argc, const char **argv, int force)
 
 	check_mergetags(commit, argc, argv);
 
-	if (write_sha1_file(buf.buf, buf.len, commit_type, new.hash))
+	if (write_sha1_file(buf.buf, buf.len, commit_type, &new))
 		die(_("could not write replacement commit for: '%s'"), old_ref);
 
 	strbuf_release(&buf);

index a7e6a5b0f2..7ef659576e 100644
@@ -187,7 +187,7 @@ static int build_tag_object(struct strbuf *buf, int sign, struct object_id *resu
 {
 	if (sign && do_sign(buf) < 0)
 		return error(_("unable to sign the tag"));
-	if (write_sha1_file(buf->buf, buf->len, tag_type, result->hash) < 0)
+	if (write_sha1_file(buf->buf, buf->len, tag_type, result) < 0)
 		return error(_("unable to write tag file"));
 	return 0;
 }

index 2e494e2a4b..a08f4e2544 100644
@@ -172,7 +172,8 @@ static void write_cached_object(struct object *obj, struct obj_buffer *obj_buf)
 {
 	struct object_id oid;
 
-	if (write_sha1_file(obj_buf->buffer, obj_buf->size, typename(obj->type), oid.hash) < 0)
+	if (write_sha1_file(obj_buf->buffer, obj_buf->size, typename(obj->type),
+			    &oid) < 0)
 		die("failed to write object %s", oid_to_hex(&obj->oid));
 	obj->flags |= FLAG_WRITTEN;
 }

@@ -237,14 +238,16 @@ static void write_object(unsigned nr, enum object_type type,
 			 void *buf, unsigned long size)
 {
 	if (!strict) {
-		if (write_sha1_file(buf, size, typename(type), obj_list[nr].oid.hash) < 0)
+		if (write_sha1_file(buf, size, typename(type),
+				    &obj_list[nr].oid) < 0)
 			die("failed to write object");
 		added_object(nr, type, buf, size);
 		free(buf);
 		obj_list[nr].obj = NULL;
 	} else if (type == OBJ_BLOB) {
 		struct blob *blob;
-		if (write_sha1_file(buf, size, typename(type), obj_list[nr].oid.hash) < 0)
+		if (write_sha1_file(buf, size, typename(type),
+				    &obj_list[nr].oid) < 0)
 			die("failed to write object");
 		added_object(nr, type, buf, size);
 		free(buf);

index 0df09180ee..2080778039 100644
@@ -408,7 +408,7 @@ static int update_one(struct cache_tree *it,
 			to_invalidate = 1;
 	} else if (dryrun)
 		hash_sha1_file(buffer.buf, buffer.len, tree_type, &it->oid);
-	else if (write_sha1_file(buffer.buf, buffer.len, tree_type, it->oid.hash)) {
+	else if (write_sha1_file(buffer.buf, buffer.len, tree_type, &it->oid)) {
 		strbuf_release(&buffer);
 		return -1;
 	}

index cf98573805..3fe0818c30 100644
@@ -1238,7 +1238,8 @@ static inline const unsigned char *lookup_replace_object(const unsigned char *sh
 extern int sha1_object_info(const unsigned char *, unsigned long *);
 extern int hash_sha1_file(const void *buf, unsigned long len, const char *type,
 			  struct object_id *oid);
-extern int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *return_sha1);
+extern int write_sha1_file(const void *buf, unsigned long len, const char *type,
+			   struct object_id *oid);
 extern int hash_sha1_file_literally(const void *buf, unsigned long len, const char *type, struct object_id *oid, unsigned flags);
 extern int pretend_sha1_file(void *, unsigned long, enum object_type,
 			     struct object_id *oid);

index 760137e54b..dc506f59d2 100644
@@ -1582,7 +1582,7 @@ int commit_tree_extended(const char *msg, size_t msg_len,
 		goto out;
 	}
 
-	result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret->hash);
+	result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
 out:
 	strbuf_release(&buffer);
 	return result;

index 0f899a7212..1fa054b079 100644
@@ -214,7 +214,7 @@ static int splice_tree(const struct object_id *hash1, const char *prefix,
 		rewrite_with = hash2;
 	}
 	oidcpy(rewrite_here, rewrite_with);
-	status = write_sha1_file(buf, sz, tree_type, result->hash);
+	status = write_sha1_file(buf, sz, tree_type, result);
 	free(buf);
 	return status;
 }

index 0fc580d8ca..a17156e214 100644
@@ -1009,8 +1009,9 @@ static int merge_file_1(struct merge_options *o,
 			if ((merge_status < 0) || !result_buf.ptr)
 				ret = err(o, _("Failed to execute internal merge"));
 
-			if (!ret && write_sha1_file(result_buf.ptr, result_buf.size,
-						    blob_type, result->oid.hash))
+			if (!ret &&
+			    write_sha1_file(result_buf.ptr, result_buf.size,
+					    blob_type, &result->oid))
 				ret = err(o, _("Unable to add %s to database"),
 					  a->path);
 

index 010ad236cb..cddb31b72f 100644
@@ -88,7 +88,7 @@ int notes_cache_put(struct notes_cache *c, struct object_id *key_oid,
 {
 	struct object_id value_oid;
 
-	if (write_sha1_file(data, size, "blob", value_oid.hash) < 0)
+	if (write_sha1_file(data, size, "blob", &value_oid) < 0)
 		return -1;
 	return add_note(&c->tree, key_oid, &value_oid, NULL);
 }

index 09ef1ce33a..2764969bcf 100644
@@ -667,7 +667,7 @@ static int tree_write_stack_finish_subtree(struct tree_write_stack *tws)
 		ret = tree_write_stack_finish_subtree(n);
 		if (ret)
 			return ret;
-		ret = write_sha1_file(n->buf.buf, n->buf.len, tree_type, s.hash);
+		ret = write_sha1_file(n->buf.buf, n->buf.len, tree_type, &s);
 		if (ret)
 			return ret;
 		strbuf_release(&n->buf);

@@ -825,7 +825,7 @@ int combine_notes_concatenate(struct object_id *cur_oid,
 	free(new_msg);
 
 	/* create a new blob object from buf */
-	ret = write_sha1_file(buf, buf_len, blob_type, cur_oid->hash);
+	ret = write_sha1_file(buf, buf_len, blob_type, cur_oid);
 	free(buf);
 	return ret;
 }

@@ -905,7 +905,7 @@ int combine_notes_cat_sort_uniq(struct object_id *cur_oid,
 				 string_list_join_lines_helper, &buf))
 		goto out;
 
-	ret = write_sha1_file(buf.buf, buf.len, blob_type, cur_oid->hash);
+	ret = write_sha1_file(buf.buf, buf.len, blob_type, cur_oid);
 
 out:
 	strbuf_release(&buf);

@@ -1147,8 +1147,7 @@ int write_notes_tree(struct notes_tree *t, struct object_id *result)
 	ret = for_each_note(t, flags, write_each_note, &cb_data) ||
 	      write_each_non_note_until(NULL, &cb_data) ||
 	      tree_write_stack_finish_subtree(&root) ||
-	      write_sha1_file(root.buf.buf, root.buf.len, tree_type,
-			      result->hash);
+	      write_sha1_file(root.buf.buf, root.buf.len, tree_type, result);
 	strbuf_release(&root.buf);
 	return ret;
 }

index 2eb81a66b9..79c21944ef 100644
@@ -631,10 +631,10 @@ static struct cache_entry *create_alias_ce(struct index_state *istate,
 
 void set_object_name_for_intent_to_add_entry(struct cache_entry *ce)
 {
-	unsigned char sha1[20];
-	if (write_sha1_file("", 0, blob_type, sha1))
+	struct object_id oid;
+	if (write_sha1_file("", 0, blob_type, &oid))
 		die("cannot create an empty blob in the object database");
-	hashcpy(ce->oid.hash, sha1);
+	oidcpy(&ce->oid, &oid);
 }
 
 int add_to_index(struct index_state *istate, const char *path, struct stat *st, int flags)

index 88b960316c..b7baf69041 100644
@@ -1420,8 +1420,8 @@ void *read_object_with_reference(const unsigned char *sha1,
 }
 
 static void write_sha1_file_prepare(const void *buf, unsigned long len,
-                                    const char *type, unsigned char *sha1,
-                                    char *hdr, int *hdrlen)
+				    const char *type, struct object_id *oid,
+				    char *hdr, int *hdrlen)
 {
 	git_SHA_CTX c;
 

@@ -1432,7 +1432,7 @@ static void write_sha1_file_prepare(const void *buf, unsigned long len,
 	git_SHA1_Init(&c);
 	git_SHA1_Update(&c, hdr, *hdrlen);
 	git_SHA1_Update(&c, buf, len);
-	git_SHA1_Final(sha1, &c);
+	git_SHA1_Final(oid->hash, &c);
 }
 
 /*

@@ -1490,7 +1490,7 @@ int hash_sha1_file(const void *buf, unsigned long len, const char *type,
 {
 	char hdr[32];
 	int hdrlen = sizeof(hdr);
-	write_sha1_file_prepare(buf, len, type, oid->hash, hdr, &hdrlen);
+	write_sha1_file_prepare(buf, len, type, oid, hdr, &hdrlen);
 	return 0;
 }
 

@@ -1633,7 +1633,8 @@ static int freshen_packed_object(const unsigned char *sha1)
 	return 1;
 }
 
-int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1)
+int write_sha1_file(const void *buf, unsigned long len, const char *type,
+		    struct object_id *oid)
 {
 	char hdr[32];
 	int hdrlen = sizeof(hdr);

@@ -1641,10 +1642,10 @@ int write_sha1_file(const void *buf, unsigned long len, const char *type, unsign
 	/* Normally if we have it in the pack then we do not bother writing
 	 * it out into .git/objects/??/?{38} file.
 	 */
-	write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
-	if (freshen_packed_object(sha1) || freshen_loose_object(sha1))
+	write_sha1_file_prepare(buf, len, type, oid, hdr, &hdrlen);
+	if (freshen_packed_object(oid->hash) || freshen_loose_object(oid->hash))
 		return 0;
-	return write_loose_object(sha1, hdr, hdrlen, buf, len, 0);
+	return write_loose_object(oid->hash, hdr, hdrlen, buf, len, 0);
 }
 
 int hash_sha1_file_literally(const void *buf, unsigned long len, const char *type,

@@ -1656,7 +1657,7 @@ int hash_sha1_file_literally(const void *buf, unsigned long len, const char *typ
 	/* type string, SP, %lu of the length plus NUL must fit this */
 	hdrlen = strlen(type) + 32;
 	header = xmalloc(hdrlen);
-	write_sha1_file_prepare(buf, len, type, oid->hash, header, &hdrlen);
+	write_sha1_file_prepare(buf, len, type, oid, header, &hdrlen);
 
 	if (!(flags & HASH_WRITE_OBJECT))
 		goto cleanup;

@@ -1767,7 +1768,7 @@ static int index_mem(struct object_id *oid, void *buf, size_t size,
 	}
 
 	if (write_object)
-		ret = write_sha1_file(buf, size, typename(type), oid->hash);
+		ret = write_sha1_file(buf, size, typename(type), oid);
 	else
 		ret = hash_sha1_file(buf, size, typename(type), oid);
 	if (re_allocated)

@@ -1790,7 +1791,7 @@ static int index_stream_convert_blob(struct object_id *oid, int fd,
 
 	if (write_object)
 		ret = write_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
-				      oid->hash);
+				      oid);
 	else
 		ret = hash_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
 				     oid);

@@ -1908,7 +1909,7 @@ int index_path(struct object_id *oid, const char *path, struct stat *st, unsigne
 			return error_errno("readlink(\"%s\")", path);
 		if (!(flags & HASH_WRITE_OBJECT))
 			hash_sha1_file(sb.buf, sb.len, blob_type, oid);
-		else if (write_sha1_file(sb.buf, sb.len, blob_type, oid->hash))
+		else if (write_sha1_file(sb.buf, sb.len, blob_type, oid))
 			rc = error("%s: failed to insert into database", path);
 		strbuf_release(&sb);
 		break;

index 14435ab65d..0913f8ab86 100644
@@ -915,6 +915,10 @@ static struct remote_lock *lock_remote(const char *path, long timeout)
 				lock->timeout = -1;
 			}
 			XML_ParserFree(parser);
+		} else {
+			fprintf(stderr,
+				"error: curl result=%d, HTTP code=%ld\n",
+				results.curl_result, results.http_code);
 		}
 	} else {
 		fprintf(stderr, "Unable to start LOCK request\n");

index 2893f3c103..1fc22b304b 100644
@@ -232,7 +232,7 @@ static struct commit *fake_working_tree_commit(struct diff_options *opt,
 	convert_to_git(&the_index, path, buf.buf, buf.len, &buf, 0);
 	origin->file.ptr = buf.buf;
 	origin->file.size = buf.len;
-	pretend_sha1_file(buf.buf, buf.len, OBJ_BLOB, origin->blob_oid.hash);
+	pretend_object_file(buf.buf, buf.len, OBJ_BLOB, &origin->blob_oid);
 
 	/*
 	 * Read the current index, replace the path entry with

index d8b975a571..e4e03ac51d 100644
@@ -1241,7 +1241,10 @@ extern int sha1_object_info(const unsigned char *, unsigned long *);
 extern int hash_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1);
 extern int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *return_sha1);
 extern int hash_sha1_file_literally(const void *buf, unsigned long len, const char *type, struct object_id *oid, unsigned flags);
-extern int pretend_sha1_file(void *, unsigned long, enum object_type, unsigned char *);
+
+extern int pretend_object_file(void *, unsigned long, enum object_type,
+			       struct object_id *oid);
+
 extern int force_object_loose(const unsigned char *sha1, time_t mtime);
 extern int git_open_cloexec(const char *name, int flags);
 #define git_open(name) git_open_cloexec(name, O_RDONLY)

index 3da70ac650..830b93b428 100644
@@ -1312,13 +1312,13 @@ static void *read_object(const unsigned char *sha1, enum object_type *type,
 	return content;
 }
 
-int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
-		      unsigned char *sha1)
+int pretend_object_file(void *buf, unsigned long len, enum object_type type,
+			struct object_id *oid)
 {
 	struct cached_object *co;
 
-	hash_sha1_file(buf, len, typename(type), sha1);
-	if (has_sha1_file(sha1) || find_cached_object(sha1))
+	hash_sha1_file(buf, len, typename(type), oid->hash);
+	if (has_sha1_file(oid->hash) || find_cached_object(oid->hash))
 		return 0;
 	ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);
 	co = &cached_objects[cached_object_nr++];

@@ -1326,7 +1326,7 @@ int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
 	co->type = type;
 	co->buf = xmalloc(len);
 	memcpy(co->buf, buf, len);
-	hashcpy(co->sha1, sha1);
+	hashcpy(co->sha1, oid->hash);
 	return 0;
 }
 

index e4e03ac51d..ed72933ba7 100644
@@ -1047,8 +1047,6 @@ extern const struct object_id empty_tree_oid;
 	"\xe6\x9d\xe2\x9b\xb2\xd1\xd6\x43\x4b\x8b" \
 	"\x29\xae\x77\x5a\xd8\xc2\xe4\x8c\x53\x91"
 extern const struct object_id empty_blob_oid;
-#define EMPTY_BLOB_SHA1_BIN (empty_blob_oid.hash)
-
 
 static inline int is_empty_blob_sha1(const unsigned char *sha1)
 {

141 lines not on this page · raw message

index 11a047ba48..e7bb786a33 100644
@@ -74,9 +74,9 @@ struct exclude_list_group {
 	struct exclude_list *el;
 };
 
-struct sha1_stat {
+struct oid_stat {
 	struct stat_data stat;
-	unsigned char sha1[20];
+	struct object_id oid;
 	int valid;
 };
 

@@ -124,8 +124,8 @@ struct untracked_cache_dir {
 };
 
 struct untracked_cache {
-	struct sha1_stat ss_info_exclude;
-	struct sha1_stat ss_excludes_file;
+	struct oid_stat ss_info_exclude;
+	struct oid_stat ss_excludes_file;
 	const char *exclude_per_dir;
 	struct strbuf ident;
 	/*

@@ -195,8 +195,8 @@ struct dir_struct {
 
 	/* Enable untracked file cache if set */
 	struct untracked_cache *untracked;
-	struct sha1_stat ss_info_exclude;
-	struct sha1_stat ss_excludes_file;
+	struct oid_stat ss_info_exclude;
+	struct oid_stat ss_excludes_file;
 	unsigned unmanaged_exclude_files;
 };
 

index f752532ffb..d7c55c2355 100644
@@ -54,8 +54,8 @@ int cmd_main(int ac, const char **av)
 		printf("no untracked cache\n");
 		return 0;
 	}
-	printf("info/exclude %s\n", sha1_to_hex(uc->ss_info_exclude.sha1));
-	printf("core.excludesfile %s\n", sha1_to_hex(uc->ss_excludes_file.sha1));
+	printf("info/exclude %s\n", oid_to_hex(&uc->ss_info_exclude.oid));
+	printf("core.excludesfile %s\n", oid_to_hex(&uc->ss_excludes_file.oid));
 	printf("exclude_per_dir %s\n", uc->exclude_per_dir);
 	printf("flags %08x\n", uc->dir_flags);
 	if (uc->root)

index 321a9fa68d..57ab8a8a29 100644
@@ -3154,7 +3154,7 @@ static int apply_binary(struct apply_state *state,
 		 * See if the old one matches what the patch
 		 * applies to.
 		 */
-		hash_sha1_file(img->buf, img->len, blob_type, oid.hash);
+		hash_object_file(img->buf, img->len, blob_type, &oid);
 		if (strcmp(oid_to_hex(&oid), patch->old_sha1_prefix))
 			return error(_("the patch applies to '%s' (%s), "
 				       "which does not match the "

@@ -3199,7 +3199,7 @@ static int apply_binary(struct apply_state *state,
 				     name);
 
 		/* verify that the result matches */
-		hash_sha1_file(img->buf, img->len, blob_type, oid.hash);
+		hash_object_file(img->buf, img->len, blob_type, &oid);
 		if (strcmp(oid_to_hex(&oid), patch->new_sha1_prefix))
 			return error(_("binary patch to '%s' creates incorrect result (expecting %s, got %s)"),
 				name, patch->new_sha1_prefix, oid_to_hex(&oid));

index 4c51aec81f..7f5a95e6ff 100644
@@ -958,9 +958,8 @@ static void resolve_delta(struct object_entry *delta_obj,
 	free(delta_data);
 	if (!result->data)
 		bad_object(delta_obj->idx.offset, _("failed to apply delta"));
-	hash_sha1_file(result->data, result->size,
-		       typename(delta_obj->real_type),
-		       delta_obj->idx.oid.hash);
+	hash_object_file(result->data, result->size,
+			 typename(delta_obj->real_type), &delta_obj->idx.oid);
 	sha1_object(result->data, NULL, result->size, delta_obj->real_type,
 		    &delta_obj->idx.oid);
 	counter_lock();

index 10078ae371..814bf6bfde 100644
@@ -355,7 +355,7 @@ static void check_one_mergetag(struct commit *commit,
 	struct tag *tag;
 	int i;
 
-	hash_sha1_file(extra->value, extra->len, typename(OBJ_TAG), tag_oid.hash);
+	hash_object_file(extra->value, extra->len, typename(OBJ_TAG), &tag_oid);
 	tag = lookup_tag(&tag_oid);
 	if (!tag)
 		die(_("bad mergetag in commit '%s'"), ref);

index 62ea264c46..85a40d1af7 100644
@@ -258,7 +258,7 @@ static void write_object(unsigned nr, enum object_type type,
 	} else {
 		struct object *obj;
 		int eaten;
-		hash_sha1_file(buf, size, typename(type), obj_list[nr].oid.hash);
+		hash_object_file(buf, size, typename(type), &obj_list[nr].oid);
 		added_object(nr, type, buf, size);
 		obj = parse_object_buffer(&obj_list[nr].oid, type, size, buf,
 					  &eaten);

index e03e72c34a..6574eeb80d 100644
@@ -400,15 +400,14 @@ static int update_one(struct cache_tree *it,
 	}
 
 	if (repair) {
-		unsigned char sha1[20];
-		hash_sha1_file(buffer.buf, buffer.len, tree_type, sha1);
-		if (has_sha1_file(sha1))
-			hashcpy(it->oid.hash, sha1);
+		struct object_id oid;
+		hash_object_file(buffer.buf, buffer.len, tree_type, &oid);
+		if (has_sha1_file(oid.hash))
+			oidcpy(&it->oid, &oid);
 		else
 			to_invalidate = 1;
 	} else if (dryrun)
-		hash_sha1_file(buffer.buf, buffer.len, tree_type,
-			       it->oid.hash);
+		hash_object_file(buffer.buf, buffer.len, tree_type, &it->oid);
 	else if (write_sha1_file(buffer.buf, buffer.len, tree_type, it->oid.hash)) {
 		strbuf_release(&buffer);
 		return -1;

index ed72933ba7..08f2b81e1b 100644
@@ -1236,7 +1236,10 @@ static inline const unsigned char *lookup_replace_object(const unsigned char *sh
 
 /* Read and unpack a sha1 file into memory, write memory to a sha1 file */
 extern int sha1_object_info(const unsigned char *, unsigned long *);
-extern int hash_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1);
+
+extern int hash_object_file(const void *buf, unsigned long len,
+			    const char *type, struct object_id *oid);
+
 extern int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *return_sha1);
 extern int hash_sha1_file_literally(const void *buf, unsigned long len, const char *type, struct object_id *oid, unsigned flags);
 

index 1a41a48e15..d25a4757ad 100644
@@ -898,7 +898,7 @@ static int ident_to_git(const char *path, const char *src, size_t len,
 static int ident_to_worktree(const char *path, const char *src, size_t len,
                              struct strbuf *buf, int ident)
 {
-	unsigned char sha1[20];
+	struct object_id oid;
 	char *to_free = NULL, *dollar, *spc;
 	int cnt;
 

@@ -912,7 +912,7 @@ static int ident_to_worktree(const char *path, const char *src, size_t len,
 	/* are we "faking" in place editing ? */
 	if (src == buf->buf)
 		to_free = strbuf_detach(buf, NULL);
-	hash_sha1_file(src, len, "blob", sha1);
+	hash_object_file(src, len, "blob", &oid);
 
 	strbuf_grow(buf, len + cnt * 43);
 	for (;;) {

@@ -969,7 +969,7 @@ static int ident_to_worktree(const char *path, const char *src, size_t len,
 
 		/* step 4: substitute */
 		strbuf_addstr(buf, "Id: ");
-		strbuf_add(buf, sha1_to_hex(sha1), 40);
+		strbuf_add(buf, sha1_to_hex(oid.hash), GIT_SHA1_HEXSZ);
 		strbuf_addstr(buf, " $");
 	}
 	strbuf_add(buf, src, len);

index 245e999fe5..e27d0bb632 100644
@@ -260,8 +260,8 @@ static unsigned int hash_filespec(struct diff_filespec *filespec)
 	if (!filespec->oid_valid) {
 		if (diff_populate_filespec(filespec, 0))
 			return 0;
-		hash_sha1_file(filespec->data, filespec->size, "blob",
-			       filespec->oid.hash);
+		hash_object_file(filespec->data, filespec->size, "blob",
+				 &filespec->oid);
 	}
 	return sha1hash(filespec->oid.hash);
 }

index ef977b8657..177f9027be 100644
@@ -846,8 +846,8 @@ static int add_excludes(const char *fname, const char *base, int baselen,
 				oidcpy(&sha1_stat->oid,
 				       &istate->cache[pos]->oid);
 			else
-				hash_sha1_file(buf, size, "blob",
-					       sha1_stat->oid.hash);
+				hash_object_file(buf, size, "blob",
+						 &sha1_stat->oid);
 			fill_stat_data(&sha1_stat->stat, &st);
 			sha1_stat->valid = 1;
 		}

index fca29d4799..fc0cc0d6d1 100644
@@ -499,7 +499,7 @@ static void show_one_mergetag(struct commit *commit,
 	int status, nth;
 	size_t payload_size, gpg_message_offset;
 
-	hash_sha1_file(extra->value, extra->len, typename(OBJ_TAG), oid.hash);
+	hash_object_file(extra->value, extra->len, typename(OBJ_TAG), &oid);
 	tag = lookup_tag(&oid);
 	if (!tag)
 		return; /* error message already given */

index 830b93b428..4c44c60cec 100644
@@ -788,7 +788,7 @@ void *xmmap(void *start, size_t length,
 int check_sha1_signature(const unsigned char *sha1, void *map,
 			 unsigned long size, const char *type)
 {
-	unsigned char real_sha1[20];
+	struct object_id real_oid;
 	enum object_type obj_type;
 	struct git_istream *st;
 	git_SHA_CTX c;

@@ -796,8 +796,8 @@ int check_sha1_signature(const unsigned char *sha1, void *map,
 	int hdrlen;
 
 	if (map) {
-		hash_sha1_file(map, size, type, real_sha1);
-		return hashcmp(sha1, real_sha1) ? -1 : 0;
+		hash_object_file(map, size, type, &real_oid);
+		return hashcmp(sha1, real_oid.hash) ? -1 : 0;
 	}
 
 	st = open_istream(sha1, &obj_type, &size, NULL);

@@ -822,9 +822,9 @@ int check_sha1_signature(const unsigned char *sha1, void *map,
 			break;
 		git_SHA1_Update(&c, buf, readlen);
 	}
-	git_SHA1_Final(real_sha1, &c);
+	git_SHA1_Final(real_oid.hash, &c);
 	close_istream(st);
-	return hashcmp(sha1, real_sha1) ? -1 : 0;
+	return hashcmp(sha1, real_oid.hash) ? -1 : 0;
 }
 
 int git_open_cloexec(const char *name, int flags)

@@ -1317,7 +1317,7 @@ int pretend_object_file(void *buf, unsigned long len, enum object_type type,
 {
 	struct cached_object *co;
 
-	hash_sha1_file(buf, len, typename(type), oid->hash);
+	hash_object_file(buf, len, typename(type), oid);
 	if (has_sha1_file(oid->hash) || find_cached_object(oid->hash))
 		return 0;
 	ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);

@@ -1485,12 +1485,12 @@ static int write_buffer(int fd, const void *buf, size_t len)
 	return 0;
 }
 
-int hash_sha1_file(const void *buf, unsigned long len, const char *type,
-                   unsigned char *sha1)
+int hash_object_file(const void *buf, unsigned long len, const char *type,
+		     struct object_id *oid)
 {
 	char hdr[32];
 	int hdrlen = sizeof(hdr);
-	write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
+	write_sha1_file_prepare(buf, len, type, oid->hash, hdr, &hdrlen);
 	return 0;
 }
 

@@ -1769,7 +1769,7 @@ static int index_mem(struct object_id *oid, void *buf, size_t size,
 	if (write_object)
 		ret = write_sha1_file(buf, size, typename(type), oid->hash);
 	else
-		ret = hash_sha1_file(buf, size, typename(type), oid->hash);
+		ret = hash_object_file(buf, size, typename(type), oid);
 	if (re_allocated)
 		free(buf);
 	return ret;

@@ -1792,8 +1792,8 @@ static int index_stream_convert_blob(struct object_id *oid, int fd,
 		ret = write_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
 				      oid->hash);
 	else
-		ret = hash_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
-				     oid->hash);
+		ret = hash_object_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
+				       oid);
 	strbuf_release(&sbuf);
 	return ret;
 }

@@ -1907,7 +1907,7 @@ int index_path(struct object_id *oid, const char *path, struct stat *st, unsigne
 		if (strbuf_readlink(&sb, path, st->st_size))
 			return error_errno("readlink(\"%s\")", path);
 		if (!(flags & HASH_WRITE_OBJECT))
-			hash_sha1_file(sb.buf, sb.len, blob_type, oid->hash);
+			hash_object_file(sb.buf, sb.len, blob_type, oid);
 		else if (write_sha1_file(sb.buf, sb.len, blob_type, oid->hash))
 			rc = error("%s: failed to insert into database", path);
 		strbuf_release(&sb);

index 08f2b81e1b..d5d78d6a51 100644
@@ -1029,7 +1029,7 @@ static inline void hashclr(unsigned char *hash)
 
 static inline void oidclr(struct object_id *oid)
 {
-	hashclr(oid->hash);
+	memset(oid->hash, 0, GIT_MAX_RAWSZ);
 }
 
 

index 396b7338df..0f899a7212 100644
@@ -161,19 +161,17 @@ static void match_trees(const struct object_id *hash1,
  * A tree "hash1" has a subdirectory at "prefix".  Come up with a
  * tree object by replacing it with another tree "hash2".
  */
-static int splice_tree(const unsigned char *hash1,
-		       const char *prefix,
-		       const unsigned char *hash2,
-		       unsigned char *result)
+static int splice_tree(const struct object_id *hash1, const char *prefix,
+		       const struct object_id *hash2, struct object_id *result)
 {
 	char *subpath;
 	int toplen;
 	char *buf;
 	unsigned long sz;
 	struct tree_desc desc;
-	unsigned char *rewrite_here;
-	const unsigned char *rewrite_with;
-	unsigned char subtree[20];
+	struct object_id *rewrite_here;
+	const struct object_id *rewrite_with;
+	struct object_id subtree;
 	enum object_type type;
 	int status;
 

@@ -182,9 +180,9 @@ static int splice_tree(const unsigned char *hash1,
 	if (*subpath)
 		subpath++;
 
-	buf = read_sha1_file(hash1, &type, &sz);
+	buf = read_sha1_file(hash1->hash, &type, &sz);
 	if (!buf)
-		die("cannot read tree %s", sha1_to_hex(hash1));
+		die("cannot read tree %s", oid_to_hex(hash1));
 	init_tree_desc(&desc, buf, sz);
 
 	rewrite_here = NULL;

@@ -197,26 +195,26 @@ static int splice_tree(const unsigned char *hash1,
 		if (strlen(name) == toplen &&
 		    !memcmp(name, prefix, toplen)) {
 			if (!S_ISDIR(mode))
-				die("entry %s in tree %s is not a tree",
-				    name, sha1_to_hex(hash1));
-			rewrite_here = (unsigned char *) oid->hash;
+				die("entry %s in tree %s is not a tree", name,
+				    oid_to_hex(hash1));
+			rewrite_here = (struct object_id *)oid;
 			break;
 		}
 		update_tree_entry(&desc);
 	}
 	if (!rewrite_here)
-		die("entry %.*s not found in tree %s",
-		    toplen, prefix, sha1_to_hex(hash1));
+		die("entry %.*s not found in tree %s", toplen, prefix,
+		    oid_to_hex(hash1));
 	if (*subpath) {
-		status = splice_tree(rewrite_here, subpath, hash2, subtree);
+		status = splice_tree(rewrite_here, subpath, hash2, &subtree);
 		if (status)
 			return status;
-		rewrite_with = subtree;
-	}
-	else
+		rewrite_with = &subtree;
+	} else {
 		rewrite_with = hash2;
-	hashcpy(rewrite_here, rewrite_with);
-	status = write_sha1_file(buf, sz, tree_type, result);
+	}
+	oidcpy(rewrite_here, rewrite_with);
+	status = write_sha1_file(buf, sz, tree_type, result->hash);
 	free(buf);
 	return status;
 }

@@ -280,7 +278,7 @@ void shift_tree(const struct object_id *hash1,
 	if (!*add_prefix)
 		return;
 
-	splice_tree(hash1->hash, add_prefix, hash2->hash, shifted->hash);
+	splice_tree(hash1, add_prefix, hash2, shifted);
 }
 
 /*

@@ -334,7 +332,7 @@ void shift_tree_by(const struct object_id *hash1,
 		 * shift tree2 down by adding shift_prefix above it
 		 * to match tree1.
 		 */
-		splice_tree(hash1->hash, shift_prefix, hash2->hash, shifted->hash);
+		splice_tree(hash1, shift_prefix, hash2, shifted);
 	else
 		/*
 		 * shift tree2 up by removing shift_prefix from it

index 396b7338df..a8dc8a53d9 100644
@@ -171,7 +171,7 @@ static int splice_tree(const unsigned char *hash1,
 	char *buf;
 	unsigned long sz;
 	struct tree_desc desc;
-	unsigned char *rewrite_here;
+	const object_id *rewrite_here;
 	const unsigned char *rewrite_with;
 	unsigned char subtree[20];
 	enum object_type type;

@@ -199,7 +199,7 @@ static int splice_tree(const unsigned char *hash1,
 			if (!S_ISDIR(mode))
 				die("entry %s in tree %s is not a tree",
 				    name, sha1_to_hex(hash1));
-			rewrite_here = (unsigned char *) oid->hash;
+			rewrite_here = oid->hash;
 			break;
 		}
 		update_tree_entry(&desc);

@@ -215,7 +215,7 @@ static int splice_tree(const unsigned char *hash1,
 	}
 	else
 		rewrite_with = hash2;
-	hashcpy(rewrite_here, rewrite_with);
+	replace_tree_entry_hash(&desc, rewrite_with, buf, sz);
 	status = write_sha1_file(buf, sz, tree_type, result);
 	free(buf);
 	return status;

index 63a87ed666..f31a03569f 100644
@@ -164,6 +164,17 @@ int tree_entry_gently(struct tree_desc *desc, struct name_entry *entry)
 	return 1;
 }
 
+void replace_tree_entry_hash(struct tree_desc *desc,
+			     const unsigned char *sha1,
+			     char *buf, unsigned long size)
+{
+	unsigned long offset = (const char *)desc->buffer - buf;
+	unsigned char *to_update;
+
+	to_update = (unsigned char *)buf + offset + tree_entry_len(&desc->entry);
+	hashcpy(to_update, sha1);
+}
+
 void setup_traverse_info(struct traverse_info *info, const char *base)
 {
 	int pathlen = strlen(base);

index b6bd1b4ccf..9a7d133d68 100644
@@ -35,6 +35,9 @@ int update_tree_entry_gently(struct tree_desc *);
 void init_tree_desc(struct tree_desc *desc, const void *buf, unsigned long size);
 int init_tree_desc_gently(struct tree_desc *desc, const void *buf, unsigned long size);
 
+void replace_tree_entry_hash(struct tree_desc *desc,
+			     const unsigned char *sha1,
+			     char *buf, unsigned long size);
 /*
  * Helper function that does both tree_entry_extract() and update_tree_entry()
  * and returns true for success

index acfe9d3c8c..6e6abb05cd 100644
@@ -1641,8 +1641,8 @@ static void do_commit(const struct am_state *state)
 		setenv("GIT_COMMITTER_DATE",
 			state->ignore_date ? "" : state->author_date, 1);
 
-	if (commit_tree(state->msg, state->msg_len, tree.hash, parents, commit.hash,
-				author, state->sign_commit))
+	if (commit_tree(state->msg, state->msg_len, &tree, parents, &commit,
+			author, state->sign_commit))
 		die(_("failed to write commit object"));
 
 	reflog_msg = getenv("GIT_REFLOG_ACTION");

index 2177251e24..e5bdf57b1e 100644
@@ -117,8 +117,8 @@ int cmd_commit_tree(int argc, const char **argv, const char *prefix)
 			die_errno("git commit-tree: failed to read");
 	}
 
-	if (commit_tree(buffer.buf, buffer.len, tree_oid.hash, parents,
-			commit_oid.hash, NULL, sign_commit)) {
+	if (commit_tree(buffer.buf, buffer.len, &tree_oid, parents, &commit_oid,
+			NULL, sign_commit)) {
 		strbuf_release(&buffer);
 		return 1;
 	}

index 8a87701414..c14878302e 100644
@@ -1792,8 +1792,9 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 		append_merge_tag_headers(parents, &tail);
 	}
 
-	if (commit_tree_extended(sb.buf, sb.len, active_cache_tree->oid.hash,
-			 parents, oid.hash, author_ident.buf, sign_commit, extra)) {
+	if (commit_tree_extended(sb.buf, sb.len, &active_cache_tree->oid,
+				 parents, &oid, author_ident.buf, sign_commit,
+				 extra)) {
 		rollback_index_files();
 		die(_("failed to write commit object"));
 	}

index 30264cfd7c..92ba99a1a5 100644
@@ -820,8 +820,8 @@ static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
 	pptr = commit_list_append(head, pptr);
 	pptr = commit_list_append(remoteheads->item, pptr);
 	prepare_to_commit(remoteheads);
-	if (commit_tree(merge_msg.buf, merge_msg.len, result_tree.hash, parents,
-			result_commit.hash, NULL, sign_commit))
+	if (commit_tree(merge_msg.buf, merge_msg.len, &result_tree, parents,
+			&result_commit, NULL, sign_commit))
 		die(_("failed to write commit object"));
 	finish(head, remoteheads, &result_commit, "In-index merge");
 	drop_save();

@@ -845,8 +845,8 @@ static int finish_automerge(struct commit *head,
 		commit_list_insert(head, &parents);
 	strbuf_addch(&merge_msg, '\n');
 	prepare_to_commit(remoteheads);
-	if (commit_tree(merge_msg.buf, merge_msg.len, result_tree->hash, parents,
-			result_commit.hash, NULL, sign_commit))
+	if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
+			&result_commit, NULL, sign_commit))
 		die(_("failed to write commit object"));
 	strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
 	finish(head, remoteheads, &result_commit, buf.buf);

index cab8d4455b..760137e54b 100644
@@ -1395,9 +1395,8 @@ void free_commit_extra_headers(struct commit_extra_header *extra)
 	}
 }
 
-int commit_tree(const char *msg, size_t msg_len,
-		const unsigned char *tree,
-		struct commit_list *parents, unsigned char *ret,
+int commit_tree(const char *msg, size_t msg_len, const struct object_id *tree,
+		struct commit_list *parents, struct object_id *ret,
 		const char *author, const char *sign_commit)
 {
 	struct commit_extra_header *extra = NULL, **tail = &extra;

@@ -1526,8 +1525,8 @@ N_("Warning: commit message did not conform to UTF-8.\n"
    "variable i18n.commitencoding to the encoding your project uses.\n");
 
 int commit_tree_extended(const char *msg, size_t msg_len,
-			 const unsigned char *tree,
-			 struct commit_list *parents, unsigned char *ret,
+			 const struct object_id *tree,
+			 struct commit_list *parents, struct object_id *ret,
 			 const char *author, const char *sign_commit,
 			 struct commit_extra_header *extra)
 {

@@ -1535,7 +1534,7 @@ int commit_tree_extended(const char *msg, size_t msg_len,
 	int encoding_is_utf8;
 	struct strbuf buffer;
 
-	assert_sha1_type(tree, OBJ_TREE);
+	assert_sha1_type(tree->hash, OBJ_TREE);
 
 	if (memchr(msg, '\0', msg_len))
 		return error("a NUL byte in commit log message not allowed.");

@@ -1544,7 +1543,7 @@ int commit_tree_extended(const char *msg, size_t msg_len,
 	encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
 
 	strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
-	strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
+	strbuf_addf(&buffer, "tree %s\n", oid_to_hex(tree));
 
 	/*
 	 * NOTE! This ordering means that the same exact tree merged with a

@@ -1583,7 +1582,7 @@ int commit_tree_extended(const char *msg, size_t msg_len,
 		goto out;
 	}
 
-	result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
+	result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret->hash);
 out:
 	strbuf_release(&buffer);
 	return result;

index 8c68ca1a5a..5dd9df4448 100644
@@ -263,14 +263,15 @@ extern void append_merge_tag_headers(struct commit_list *parents,
 				     struct commit_extra_header ***tail);
 
 extern int commit_tree(const char *msg, size_t msg_len,
-		       const unsigned char *tree,
-		       struct commit_list *parents, unsigned char *ret,
+		       const struct object_id *tree,
+		       struct commit_list *parents, struct object_id *ret,
 		       const char *author, const char *sign_commit);
 
 extern int commit_tree_extended(const char *msg, size_t msg_len,
-				const unsigned char *tree,
-				struct commit_list *parents, unsigned char *ret,
-				const char *author, const char *sign_commit,
+				const struct object_id *tree,
+				struct commit_list *parents,
+				struct object_id *ret, const char *author,
+				const char *sign_commit,
 				struct commit_extra_header *);
 
 extern struct commit_extra_header *read_commit_extra_headers(struct commit *, const char **);

index 17ee8602b3..d2f87147cc 100644
@@ -56,8 +56,8 @@ int notes_cache_write(struct notes_cache *c)
 
 	if (write_notes_tree(&c->tree, tree_oid.hash))
 		return -1;
-	if (commit_tree(c->validity, strlen(c->validity), tree_oid.hash, NULL,
-			commit_oid.hash, NULL, NULL) < 0)
+	if (commit_tree(c->validity, strlen(c->validity), &tree_oid, NULL,
+			&commit_oid, NULL, NULL) < 0)
 		return -1;
 	if (update_ref("update notes cache", c->tree.update_ref, &commit_oid,
 		       NULL, 0, UPDATE_REFS_QUIET_ON_ERR) < 0)

index 0f6573cb17..c09c5e0e47 100644
@@ -642,9 +642,8 @@ int notes_merge(struct notes_merge_options *o,
 		struct commit_list *parents = NULL;
 		commit_list_insert(remote, &parents); /* LIFO order */
 		commit_list_insert(local, &parents);
-		create_notes_commit(local_tree, parents,
-				    o->commit_msg.buf, o->commit_msg.len,
-				    result_oid->hash);
+		create_notes_commit(local_tree, parents, o->commit_msg.buf,
+				    o->commit_msg.len, result_oid);
 	}
 
 found_result:

@@ -718,8 +717,8 @@ int notes_merge_commit(struct notes_merge_options *o,
 		strbuf_setlen(&path, baselen);
 	}
 
-	create_notes_commit(partial_tree, partial_commit->parents,
-			    msg, strlen(msg), result_oid->hash);
+	create_notes_commit(partial_tree, partial_commit->parents, msg,
+			    strlen(msg), result_oid);
 	unuse_commit_buffer(partial_commit, buffer);
 	if (o->verbosity >= 4)
 		printf("Finalized notes merge commit: %s\n",

index 5c8e70c98f..058c642dac 100644
@@ -6,7 +6,7 @@
 
 void create_notes_commit(struct notes_tree *t, struct commit_list *parents,
 			 const char *msg, size_t msg_len,
-			 unsigned char *result_sha1)
+			 struct object_id *result_oid)
 {
 	struct object_id tree_oid;
 

@@ -27,7 +27,8 @@ void create_notes_commit(struct notes_tree *t, struct commit_list *parents,
 		/* else: t->ref points to nothing, assume root/orphan commit */
 	}
 
-	if (commit_tree(msg, msg_len, tree_oid.hash, parents, result_sha1, NULL, NULL))
+	if (commit_tree(msg, msg_len, &tree_oid, parents, result_oid, NULL,
+			NULL))
 		die("Failed to commit notes tree to database");
 }
 

@@ -47,7 +48,7 @@ void commit_notes(struct notes_tree *t, const char *msg)
 	strbuf_addstr(&buf, msg);
 	strbuf_complete_line(&buf);
 
-	create_notes_commit(t, NULL, buf.buf, buf.len, commit_oid.hash);
+	create_notes_commit(t, NULL, buf.buf, buf.len, &commit_oid);
 	strbuf_insert(&buf, 0, "notes: ", 7); /* commit message starts at index 7 */
 	update_ref(buf.buf, t->update_ref, &commit_oid, NULL, 0,
 		   UPDATE_REFS_DIE_ON_ERR);

index 1190578398..5d79cbef51 100644
@@ -15,7 +15,8 @@
  * The resulting commit SHA1 is stored in result_sha1.
  */
 void create_notes_commit(struct notes_tree *t, struct commit_list *parents,
-			 const char *msg, size_t msg_len, unsigned char *result_sha1);
+			 const char *msg, size_t msg_len,
+			 struct object_id *result_oid);
 
 void commit_notes(struct notes_tree *t, const char *msg);
 

index c7f21fae44..3f4f94507a 100644
@@ -270,8 +270,8 @@ static int note_tree_insert(struct notes_tree *t, struct int_node *tree,
 				if (!oidcmp(&l->val_oid, &entry->val_oid))
 					return 0;
 
-				ret = combine_notes(l->val_oid.hash,
-						    entry->val_oid.hash);
+				ret = combine_notes(&l->val_oid,
+						    &entry->val_oid);
 				if (!ret && is_null_oid(&l->val_oid))
 					note_tree_remove(t, tree, n, entry);
 				free(entry);

@@ -786,8 +786,8 @@ static int prune_notes_helper(const struct object_id *object_oid,
 	return 0;
 }
 
-int combine_notes_concatenate(unsigned char *cur_sha1,
-		const unsigned char *new_sha1)
+int combine_notes_concatenate(struct object_id *cur_oid,
+			      const struct object_id *new_oid)
 {
 	char *cur_msg = NULL, *new_msg = NULL, *buf;
 	unsigned long cur_len, new_len, buf_len;

@@ -795,18 +795,18 @@ int combine_notes_concatenate(unsigned char *cur_sha1,
 	int ret;
 
 	/* read in both note blob objects */
-	if (!is_null_sha1(new_sha1))
-		new_msg = read_sha1_file(new_sha1, &new_type, &new_len);
+	if (!is_null_oid(new_oid))
+		new_msg = read_sha1_file(new_oid->hash, &new_type, &new_len);
 	if (!new_msg || !new_len || new_type != OBJ_BLOB) {
 		free(new_msg);
 		return 0;
 	}
-	if (!is_null_sha1(cur_sha1))
-		cur_msg = read_sha1_file(cur_sha1, &cur_type, &cur_len);
+	if (!is_null_oid(cur_oid))
+		cur_msg = read_sha1_file(cur_oid->hash, &cur_type, &cur_len);
 	if (!cur_msg || !cur_len || cur_type != OBJ_BLOB) {
 		free(cur_msg);
 		free(new_msg);
-		hashcpy(cur_sha1, new_sha1);
+		oidcpy(cur_oid, new_oid);
 		return 0;
 	}
 

@@ -825,20 +825,20 @@ int combine_notes_concatenate(unsigned char *cur_sha1,
 	free(new_msg);
 
 	/* create a new blob object from buf */
-	ret = write_sha1_file(buf, buf_len, blob_type, cur_sha1);
+	ret = write_sha1_file(buf, buf_len, blob_type, cur_oid->hash);
 	free(buf);
 	return ret;
 }
 
-int combine_notes_overwrite(unsigned char *cur_sha1,
-		const unsigned char *new_sha1)
+int combine_notes_overwrite(struct object_id *cur_oid,
+			    const struct object_id *new_oid)
 {
-	hashcpy(cur_sha1, new_sha1);
+	oidcpy(cur_oid, new_oid);
 	return 0;
 }
 
-int combine_notes_ignore(unsigned char *cur_sha1,
-		const unsigned char *new_sha1)
+int combine_notes_ignore(struct object_id *cur_oid,
+			 const struct object_id *new_oid)
 {
 	return 0;
 }

@@ -848,17 +848,17 @@ int combine_notes_ignore(unsigned char *cur_sha1,
  * newlines removed.
  */
 static int string_list_add_note_lines(struct string_list *list,
-				      const unsigned char *sha1)
+				      const struct object_id *oid)
 {
 	char *data;
 	unsigned long len;
 	enum object_type t;
 
-	if (is_null_sha1(sha1))
+	if (is_null_oid(oid))
 		return 0;
 
 	/* read_sha1_file NUL-terminates */
-	data = read_sha1_file(sha1, &t, &len);
+	data = read_sha1_file(oid->hash, &t, &len);
 	if (t != OBJ_BLOB || !data || !len) {
 		free(data);
 		return t != OBJ_BLOB || !data;

@@ -884,17 +884,17 @@ static int string_list_join_lines_helper(struct string_list_item *item,
 	return 0;
 }
 
-int combine_notes_cat_sort_uniq(unsigned char *cur_sha1,
-		const unsigned char *new_sha1)
+int combine_notes_cat_sort_uniq(struct object_id *cur_oid,
+				const struct object_id *new_oid)
 {
 	struct string_list sort_uniq_list = STRING_LIST_INIT_DUP;
 	struct strbuf buf = STRBUF_INIT;
 	int ret = 1;
 
 	/* read both note blob objects into unique_lines */
-	if (string_list_add_note_lines(&sort_uniq_list, cur_sha1))
+	if (string_list_add_note_lines(&sort_uniq_list, cur_oid))
 		goto out;
-	if (string_list_add_note_lines(&sort_uniq_list, new_sha1))
+	if (string_list_add_note_lines(&sort_uniq_list, new_oid))
 		goto out;
 	string_list_remove_empty_items(&sort_uniq_list, 0);
 	string_list_sort(&sort_uniq_list);

@@ -905,7 +905,7 @@ int combine_notes_cat_sort_uniq(unsigned char *cur_sha1,
 				 string_list_join_lines_helper, &buf))
 		goto out;
 
-	ret = write_sha1_file(buf.buf, buf.len, blob_type, cur_sha1);
+	ret = write_sha1_file(buf.buf, buf.len, blob_type, cur_oid->hash);
 
 out:
 	strbuf_release(&buf);

index 3848c2fb3f..88da38b5f4 100644
@@ -9,27 +9,32 @@
  * When adding a new note annotating the same object as an existing note, it is
  * up to the caller to decide how to combine the two notes. The decision is
  * made by passing in a function of the following form. The function accepts
- * two SHA1s -- of the existing note and the new note, respectively. The
+ * two object_ids -- of the existing note and the new note, respectively. The
  * function then combines the notes in whatever way it sees fit, and writes the
- * resulting SHA1 into the first SHA1 argument (cur_sha1). A non-zero return
+ * resulting oid into the first argument (cur_oid). A non-zero return
  * value indicates failure.
  *
- * The two given SHA1s shall both be non-NULL and different from each other.
- * Either of them (but not both) may be == null_sha1, which indicates an
- * empty/non-existent note. If the resulting SHA1 (cur_sha1) is == null_sha1,
+ * The two given object_ids shall both be non-NULL and different from each
+ * other. Either of them (but not both) may be == null_oid, which indicates an
+ * empty/non-existent note. If the resulting oid (cur_oid) is == null_oid,
  * the note will be removed from the notes tree.
  *
  * The default combine_notes function (you get this when passing NULL) is
  * combine_notes_concatenate(), which appends the contents of the new note to
  * the contents of the existing note.
  */
-typedef int (*combine_notes_fn)(unsigned char *cur_sha1, const unsigned char *new_sha1);
+typedef int (*combine_notes_fn)(struct object_id *cur_oid,
+				const struct object_id *new_oid);
 
 /* Common notes combinators */
-int combine_notes_concatenate(unsigned char *cur_sha1, const unsigned char *new_sha1);
-int combine_notes_overwrite(unsigned char *cur_sha1, const unsigned char *new_sha1);
-int combine_notes_ignore(unsigned char *cur_sha1, const unsigned char *new_sha1);
-int combine_notes_cat_sort_uniq(unsigned char *cur_sha1, const unsigned char *new_sha1);
+int combine_notes_concatenate(struct object_id *cur_oid,
+			      const struct object_id *new_oid);
+int combine_notes_overwrite(struct object_id *cur_oid,
+			    const struct object_id *new_oid);
+int combine_notes_ignore(struct object_id *cur_oid,
+			 const struct object_id *new_oid);
+int combine_notes_cat_sort_uniq(struct object_id *cur_oid,
+				const struct object_id *new_oid);
 
 /*
  * Notes tree object

index d2f87147cc..010ad236cb 100644
@@ -54,7 +54,7 @@ int notes_cache_write(struct notes_cache *c)
 	if (!c->tree.dirty)
 		return 0;
 
-	if (write_notes_tree(&c->tree, tree_oid.hash))
+	if (write_notes_tree(&c->tree, &tree_oid))
 		return -1;
 	if (commit_tree(c->validity, strlen(c->validity), &tree_oid, NULL,
 			&commit_oid, NULL, NULL) < 0)

index 058c642dac..02407fe2a7 100644
@@ -12,7 +12,7 @@ void create_notes_commit(struct notes_tree *t, struct commit_list *parents,
 
 	assert(t->initialized);
 
-	if (write_notes_tree(t, tree_oid.hash))
+	if (write_notes_tree(t, &tree_oid))
 		die("Failed to write notes tree to database");
 
 	if (!parents) {

index 3f4f94507a..09ef1ce33a 100644
@@ -1123,11 +1123,12 @@ int for_each_note(struct notes_tree *t, int flags, each_note_fn fn,
 	return for_each_note_helper(t, t->root, 0, 0, flags, fn, cb_data);
 }
 
-int write_notes_tree(struct notes_tree *t, unsigned char *result)
+int write_notes_tree(struct notes_tree *t, struct object_id *result)
 {
 	struct tree_write_stack root;
 	struct write_each_note_data cb_data;
 	int ret;
+	int flags;
 
 	if (!t)
 		t = &default_notes_tree;

@@ -1141,12 +1142,13 @@ int write_notes_tree(struct notes_tree *t, unsigned char *result)
 	cb_data.next_non_note = t->first_non_note;
 
 	/* Write tree objects representing current notes tree */
-	ret = for_each_note(t, FOR_EACH_NOTE_DONT_UNPACK_SUBTREES |
-				FOR_EACH_NOTE_YIELD_SUBTREES,
-			write_each_note, &cb_data) ||
-		write_each_non_note_until(NULL, &cb_data) ||
-		tree_write_stack_finish_subtree(&root) ||
-		write_sha1_file(root.buf.buf, root.buf.len, tree_type, result);
+	flags = FOR_EACH_NOTE_DONT_UNPACK_SUBTREES |
+		FOR_EACH_NOTE_YIELD_SUBTREES;
+	ret = for_each_note(t, flags, write_each_note, &cb_data) ||
+	      write_each_non_note_until(NULL, &cb_data) ||
+	      tree_write_stack_finish_subtree(&root) ||
+	      write_sha1_file(root.buf.buf, root.buf.len, tree_type,
+			      result->hash);
 	strbuf_release(&root.buf);
 	return ret;
 }

index 88da38b5f4..0433f45db5 100644
@@ -217,7 +217,7 @@ int for_each_note(struct notes_tree *t, int flags, each_note_fn fn,
  * Write the given notes_tree structure to the object database
  *
  * Creates a new tree object encapsulating the current state of the given
- * notes_tree, and stores its SHA1 into the 'result' argument.
+ * notes_tree, and stores its object id into the 'result' argument.
  *
  * Returns zero on success, non-zero on failure.
  *