Skip to contentSkip to conversation

sha1-name.c: Fix handling of revisions that contain paths with brackets

PATCH New Stan Hu 3 participants 7 messages Dec 23, 2018 – Jan 2, 2019

lore
Share & tools
lore

Stan Hu

author
#0 lore raw

PATCH 1/1 sha1-name.c: Fix handling of revisions that contain paths with brackets

Previously, calling ls-tree with a revision such as master^{tree}:foo/{{path}} would show the root tree instead of the correct tree pointed by foo/{{path}}. If a colon is present in the revision name, peel_onion() should assume that the presence of a bracket at the end of the string belongs to the filename.

---
 sha1-name.c               | 14 +++++++++++++-
 t/t3104-ls-tree-braces.sh | 30 ++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 1 deletion(-)
 create mode 100644 t/t3104-ls-tree-braces.sh
sha1-name.c +13 -1
index faa60f69e3..69ecf0a26c 100644
@@ -1001,9 +1001,21 @@ static int peel_onion(const char *name, int len, struct object_id *oid,
 	 * "ref^{commit}".  "commit^{tree}" could be used to find the
 	 * top-level tree of the given commit.
 	 */
-	if (len < 4 || name[len-1] != '}')
+	if (len < 4)
 		return -1;
 
+	/* Check for names in ref:path format in case the path includes
+	 * brackets (e.g. ref^{type}:foo/{{bar}}).
+	 */
+	for (sp = name; sp < name + len; sp++) {
+		if (*sp == ':')
+			return -1;
+	}
+
+	if (sp == name && name[len-1] != '}') {
+		return -1;
+	}
+
 	for (sp = name + len - 1; name <= sp; sp--) {
 		int ch = *sp;
 		if (ch == '{' && name < sp && sp[-1] == '^')
t/t3104-ls-tree-braces.sh new file +30 -0
new file mode 100644
index 0000000000..3ead86c4fe
@@ -0,0 +1,30 @@
+#!/bin/sh
+
+test_description='ls-tree with a folder with braces'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	mkdir -p "newdir/{{curly}}" &&
+	touch "newdir/{{curly}}/one" &&
+	git add "newdir/{{curly}}/one" &&
+	git commit -m test
+'
+
+test_expect_success 'ls-tree with curly brace folder' '
+	cat >expect <<-EOF &&
+	100644 blob $EMPTY_BLOB	one
+	EOF
+	git ls-tree -r "HEAD:newdir/{{curly}}" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'ls-tree with type restriction and curly brace folder' '
+	cat >expect <<-EOF &&
+	100644 blob $EMPTY_BLOB	one
+	EOF
+	git ls-tree "HEAD^{tree}:newdir/{{curly}}" >actual &&
+	test_cmp expect actual
+'
+
+test_done
Signature · 1 line
2.19.1
author
#1 lore raw

PATCH 1/1 sha1-name.c: Fix handling of revisions that contain paths with brackets

Previously, calling ls-tree with a revision such as master^{tree}:foo/{{path}} would show the root tree instead of the correct tree pointed by foo/{{path}}. If a colon is present in the revision name, peel_onion() should assume that the presence of a bracket at the end of the string belongs to the filename.

---
 sha1-name.c               | 14 +++++++++++++-
 t/t3104-ls-tree-braces.sh | 30 ++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 1 deletion(-)
 create mode 100644 t/t3104-ls-tree-braces.sh
sha1-name.c +13 -1
index faa60f69e3..69ecf0a26c 100644
@@ -1001,9 +1001,21 @@ static int peel_onion(const char *name, int len, struct object_id *oid,
 	 * "ref^{commit}".  "commit^{tree}" could be used to find the
 	 * top-level tree of the given commit.
 	 */
-	if (len < 4 || name[len-1] != '}')
+	if (len < 4)
 		return -1;
 
+	/* Check for names in ref:path format in case the path includes
+	 * brackets (e.g. ref^{type}:foo/{{bar}}).
+	 */
+	for (sp = name; sp < name + len; sp++) {
+		if (*sp == ':')
+			return -1;
+	}
+
+	if (sp == name && name[len-1] != '}') {
+		return -1;
+	}
+
 	for (sp = name + len - 1; name <= sp; sp--) {
 		int ch = *sp;
 		if (ch == '{' && name < sp && sp[-1] == '^')
t/t3104-ls-tree-braces.sh new file +30 -0
new file mode 100644
index 0000000000..3ead86c4fe
@@ -0,0 +1,30 @@
+#!/bin/sh
+
+test_description='ls-tree with a folder with braces'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	mkdir -p "newdir/{{curly}}" &&
+	touch "newdir/{{curly}}/one" &&
+	git add "newdir/{{curly}}/one" &&
+	git commit -m test
+'
+
+test_expect_success 'ls-tree with curly brace folder' '
+	cat >expect <<-EOF &&
+	100644 blob $EMPTY_BLOB	one
+	EOF
+	git ls-tree -r "HEAD:newdir/{{curly}}" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'ls-tree with type restriction and curly brace folder' '
+	cat >expect <<-EOF &&
+	100644 blob $EMPTY_BLOB	one
+	EOF
+	git ls-tree "HEAD^{tree}:newdir/{{curly}}" >actual &&
+	test_cmp expect actual
+'
+
+test_done
Signature · 1 line
2.19.0
author
#2 lore raw

PATCH v2 1/1 sha1-name.c: Fix handling of revisions that contain paths with brackets

Previously, calling ls-tree with a revision such as master^{tree}:foo/{{path}} would show the root tree instead of the correct tree pointed by foo/{{path}}. If a colon is present in the revision name, peel_onion() should assume that the presence of a bracket at the end of the string belongs to the filename.

---
 sha1-name.c               | 14 +++++++++++++-
 t/t3104-ls-tree-braces.sh | 30 ++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 1 deletion(-)
 create mode 100755 t/t3104-ls-tree-braces.sh
sha1-name.c +13 -1
index faa60f69e3..588b7a53cc 100644
@@ -1001,9 +1001,21 @@ static int peel_onion(const char *name, int len, struct object_id *oid,
 	 * "ref^{commit}".  "commit^{tree}" could be used to find the
 	 * top-level tree of the given commit.
 	 */
-	if (len < 4 || name[len-1] != '}')
+	if (len < 4)
 		return -1;
 
+	/* Check for names in ref:path format in case the path includes
+	 * brackets (e.g. ref^{type}:foo/{{bar}}).
+	 */
+	for (sp = name; sp < name + len; sp++) {
+		if (*sp == ':')
+			return -1;
+	}
+
+	if (name[len-1] != '}') {
+		return -1;
+	}
+
 	for (sp = name + len - 1; name <= sp; sp--) {
 		int ch = *sp;
 		if (ch == '{' && name < sp && sp[-1] == '^')
t/t3104-ls-tree-braces.sh new file +30 -0
new file mode 100755
index 0000000000..3ead86c4fe
@@ -0,0 +1,30 @@
+#!/bin/sh
+
+test_description='ls-tree with a folder with braces'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	mkdir -p "newdir/{{curly}}" &&
+	touch "newdir/{{curly}}/one" &&
+	git add "newdir/{{curly}}/one" &&
+	git commit -m test
+'
+
+test_expect_success 'ls-tree with curly brace folder' '
+	cat >expect <<-EOF &&
+	100644 blob $EMPTY_BLOB	one
+	EOF
+	git ls-tree -r "HEAD:newdir/{{curly}}" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'ls-tree with type restriction and curly brace folder' '
+	cat >expect <<-EOF &&
+	100644 blob $EMPTY_BLOB	one
+	EOF
+	git ls-tree "HEAD^{tree}:newdir/{{curly}}" >actual &&
+	test_cmp expect actual
+'
+
+test_done
Signature · 1 line
2.19.0
#3 lore raw
Quoted 26 lines · Stan Hu

Previously, calling ls-tree with a revision such as master^{tree}:foo/{{path}} would show the root tree instead of the correct tree pointed by foo/{{path}}. If a colon is present in the revision name, peel_onion() should assume that the presence of a bracket at the end of the string belongs to the filename.

---
 sha1-name.c               | 14 +++++++++++++-
 t/t3104-ls-tree-braces.sh | 30 ++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 1 deletion(-)
 create mode 100755 t/t3104-ls-tree-braces.sh
sha1-name.c +2 -1
index faa60f69e3..588b7a53cc 100644
@@ -1001,9 +1001,21 @@ static int peel_onion(const char *name, int len, struct object_id *oid,
 	 * "ref^{commit}".  "commit^{tree}" could be used to find the
 	 * top-level tree of the given commit.
 	 */
-	if (len < 4 || name[len-1] != '}')
+	if (len < 4)
 		return -1;
 
+	/* Check for names in ref:path format in case the path includes

sha1-name.c static int peel_onion(const char *name, int len, struct object_id *oid, · line 1017

Quoted 10 lines
sha1-name.c +10 -0
+	 * brackets (e.g. ref^{type}:foo/{{bar}}).
+	 */
+	for (sp = name; sp < name + len; sp++) {
+		if (*sp == ':')
+			return -1;
+	}
+
+	if (name[len-1] != '}') {
+		return -1;
+	}

Instead of replacing one loose check (find '}' at the end) with another one, how about tighten the parsing? peel_onion() is supposed to consume all "len" characters or none so checking something like this may be better.

Note that it also shows another corner case we need to be careful
about: master^{/regex} syntax _can_ contain colons in regex. I suppose doing strchr to find the closing '}' here is better than what I did below.

--8<--

sha1-name.c +14 -9
index faa60f69e3..c9e26206ce 100644
@@ -989,7 +989,7 @@ static int peel_onion(const char *name, int len, struct object_id *oid,
 		      unsigned lookup_flags)
 {
 	struct object_id outer;
-	const char *sp;
+	const char *sp, *end;
 	unsigned int expected_type = 0;
 	struct object *o;
 
@@ -1013,21 +1013,26 @@ static int peel_onion(const char *name, int len, struct object_id *oid,
 		return -1;
 
 	sp++; /* beginning of type name, or closing brace for empty */
-	if (starts_with(sp, "commit}"))
+	if (skip_prefix(sp, "commit}", &end))
 		expected_type = OBJ_COMMIT;
-	else if (starts_with(sp, "tag}"))
+	else if (skip_prefix(sp, "tag}", &end))
 		expected_type = OBJ_TAG;
-	else if (starts_with(sp, "tree}"))
+	else if (skip_prefix(sp, "tree}", &end))
 		expected_type = OBJ_TREE;
-	else if (starts_with(sp, "blob}"))
+	else if (skip_prefix(sp, "blob}", &end))
 		expected_type = OBJ_BLOB;
-	else if (starts_with(sp, "object}"))
+	else if (skip_prefix(sp, "object}", &end))
 		expected_type = OBJ_ANY;
-	else if (sp[0] == '}')
+	else if (sp[0] == '}') {
 		expected_type = OBJ_NONE;
-	else if (sp[0] == '/')
+		end = sp + 1;
+	} else if (sp[0] == '/') {
 		expected_type = OBJ_COMMIT;
-	else
+		end = name + len;
+	} else
+		return -1;
+
+	if (end != name + len)
 		return -1;
 
 	lookup_flags &= ~GET_OID_DISAMBIGUATORS;

--8<--

--
Duy

#4 lore raw
Quoted 4 lines · Duy Nguyen

Note that it also shows another corner case we need to be careful
about: master^{/regex} syntax _can_ contain colons in regex. I suppose doing strchr to find the closing '}' here is better than what I did below.

Yes, the posted patch breaks master^{/foo:bar}, I suppose.

author
#5 lore raw

PATCH v3 1/1 sha1-name.c: Fix handling of revisions that contain paths with brackets

In reply to Duy Nguyen

Previously, calling ls-tree with a revision such as master^{tree}:foo/{{path}} would show the root tree instead of the correct tree pointed by foo/{{path}}. We improve this by ensuring peel_onion() consumes all "len" characters or none.

Note that it's also possible to have directories named ^{tree} and other patterns that look like type restrictions. To handle those cases, scan from the beginning of the name instead of the end.

---
 sha1-name.c               | 35 ++++++++++--------
 t/t3104-ls-tree-braces.sh | 75 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 96 insertions(+), 14 deletions(-)
 create mode 100755 t/t3104-ls-tree-braces.sh
sha1-name.c +21 -14
index faa60f69e3..ab372a90be 100644
@@ -989,7 +989,7 @@ static int peel_onion(const char *name, int len, struct object_id *oid,
 		      unsigned lookup_flags)
 {
 	struct object_id outer;
-	const char *sp;
+	const char *sp, *end;
 	unsigned int expected_type = 0;
 	struct object *o;
 
@@ -1001,33 +1001,40 @@ static int peel_onion(const char *name, int len, struct object_id *oid,
 	 * "ref^{commit}".  "commit^{tree}" could be used to find the
 	 * top-level tree of the given commit.
 	 */
-	if (len < 4 || name[len-1] != '}')
+	if (len < 4)
 		return -1;
 
-	for (sp = name + len - 1; name <= sp; sp--) {
+	for (sp = name; sp < name + len; sp++) {
 		int ch = *sp;
-		if (ch == '{' && name < sp && sp[-1] == '^')
+		if (ch == '^' && sp < name + len && sp[1] == '{')
 			break;
 	}
-	if (sp <= name)
+
+	if (sp == name + len)
 		return -1;
 
-	sp++; /* beginning of type name, or closing brace for empty */
-	if (starts_with(sp, "commit}"))
+	sp += 2; /* beginning of type name, or closing brace for empty */
+
+	if (skip_prefix(sp, "commit}", &end))
 		expected_type = OBJ_COMMIT;
-	else if (starts_with(sp, "tag}"))
+	else if (skip_prefix(sp, "tag}", &end))
 		expected_type = OBJ_TAG;
-	else if (starts_with(sp, "tree}"))
+	else if (skip_prefix(sp, "tree}", &end))
 		expected_type = OBJ_TREE;
-	else if (starts_with(sp, "blob}"))
+	else if (skip_prefix(sp, "blob}", &end))
 		expected_type = OBJ_BLOB;
-	else if (starts_with(sp, "object}"))
+	else if (skip_prefix(sp, "object}", &end))
 		expected_type = OBJ_ANY;
-	else if (sp[0] == '}')
+	else if (sp[0] == '}') {
 		expected_type = OBJ_NONE;
-	else if (sp[0] == '/')
+		end = sp + 1;
+	} else if (sp[0] == '/') {
 		expected_type = OBJ_COMMIT;
-	else
+		end = name + len;
+	} else
+		return -1;
+
+	if (end != name + len)
 		return -1;
 
 	lookup_flags &= ~GET_OID_DISAMBIGUATORS;
t/t3104-ls-tree-braces.sh new file +75 -0

75 lines not on this page · raw message

Signature · 1 line
2.19.1
#6 lore raw

sha1-name.c static int peel_onion(const char *name, int len, struct object_id *oid, · line 1005

Quoted 3 lines · Stan Hu
sha1-name.c +1 -1
-	if (len < 4 || name[len-1] != '}')
+	if (len < 4)
 		return -1;

The original does not expect any string given after the ^{<type>} dereferencer, like :<path>, and that is why this function returns very early for anything when name[len-1] is not a closing brace.

We do not do that anymore, because...?

This gives me a nagging feeling that the patch is barking up a wrong tree. Consider what happens when a path that does not have any funny characters, e.g. "v1.4.0^{tree}:a/b/c", is given from the top level of the request chain (e.g. "rev-parse v1.4.0^{tree}:a/b/c")? The caller must be feeding this function "v1.4.0^{tree}" after finding the colon before the path "a/b/c" and setting len to point at the colon---otherwise we won't be checking for "}" at the end like this.

When given "master^{tree}:a/b/{c}", wouldn't the caller be doing the same stripping to find the colon and calling this function with len pointing at the colon before the path (i.e. "master^{tree}")?

To put it another way, it is OK if this patch wants to shift the responsibility of finding the colon that separates the tree-ish part and the path part from the caller to this function, but then I would expect changes to the caller, because now the caller does not have to find ":a/b/c" in "v1.4.0^{tree}:a/b/c" and set up the len before calling this function. Why can the resulting code after applying this patch be correct without such a matching change?

sha1-name.c static int peel_onion(const char *name, int len, struct object_id *oid, · line 1011

Quoted 8 lines
sha1-name.c +2 -2
-	for (sp = name + len - 1; name <= sp; sp--) {
+	for (sp = name; sp < name + len; sp++) {
 		int ch = *sp;
-		if (ch == '{' && name < sp && sp[-1] == '^')
+		if (ch == '^' && sp < name + len && sp[1] == '{')
 			break;
 	}

We used to scan from the tail (as we expected that the caller gives us a (name, len) that ends with "^{<type>}". The updated code instead scans from the front, looking for "^{". I do not particularly mind the change of strategy, as long as it is correctly done, but I suspect the function will stay simpler if the callee is fixed instead.

The only troublesome case is the REV^{/...} syntax. For example,

	HEAD^{/^Git 2.0}^{tree}:t/

would want to find the commit "HEAD^{/^Git 2.0}", peel it down to a tree object with "^{tree}" and then take its "t/" subtree. It used to be that the caller (get_oid_with_context_1() has a loop that finds a colon outside "{...}" and that finds ":t/" before calling get_oid_1()) was responsible to give us "HEAD^{/^Git 2.0}^{tree}" by stripping ":t/", and I presume that it is still happening, but the above loop would terminate upon seeing "^{" immediately after HEAD, without even realizing that it has ^{tree} after it.

sha1-name.c static int peel_onion(const char *name, int len, struct object_id *oid, · line 1016

Quoted 8 lines
sha1-name.c +3 -3
-	if (sp <= name)
+
+	if (sp == name + len)
 		return -1;
 
-	sp++; /* beginning of type name, or closing brace for empty */
-	if (starts_with(sp, "commit}"))
+	sp += 2; /* beginning of type name, or closing brace for empty */

And this comment indicates that the code did not expect to see ^{/^Git 2.0} before ^{tree}.

I do not quite follow. How can this patch be correct?

Puzzled.

$ git rev-parse "master^{/^Git 2.0}^{tree}"
bc6ce29d1ec757d9d036532531a1046db4da0d96
$ ./git rev-parse "master^{/^Git 2.0}^{tree}"
master^{/^Git 2.0}^{tree}
fatal: ambiguous argument 'master^{/^Git 2.0}^{tree}': unknown revision or path not in the working tree.