Inspect reflog data programmatically in more tests

This helps for reftable support, and will help if we want to reconsider under which conditions reflogs get created/updated.

v3: pointer arithmetic for trimming newline.

Han-Wen Nienhuys (5):
show-branch: show reflog message
test-ref-store: don't add newline to reflog message
t1405: check for_each_reflog_ent_reverse() more thoroughly
test-ref-store: tweaks to for-each-reflog-ent format refs/debug: trim trailing LF from reflog message

 builtin/show-branch.c          | 12 +++++++-----
 refs/debug.c                   |  7 +++++--
 t/helper/test-ref-store.c      |  6 +++---
 t/t1400-update-ref.sh          | 13 ++++++++-----
 t/t1405-main-ref-store.sh      |  4 ++--
 t/t1406-submodule-ref-store.sh |  4 ++--
 t/t3202-show-branch.sh         | 15 +++++++++++++++
 7 files changed, 42 insertions(+), 19 deletions(-)

base-commit: abe6bb3905392d5eb6b01fa6e54d7e784e0522aa
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1145%2Fhanwen%2Freflog-prelims-v3
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1145/hanwen/reflog-prelims-v3
Pull-Request: https://github.com/git/git/pull/1145

Range-diff vs v2:

 1:  9d8394d8c76 = 1:  6e94a6fbe05 show-branch: show reflog message
 2:  4a86d212589 ! 2:  062481ffece test-ref-store: don't add newline to reflog message

@@ Metadata
## Commit message ##
test-ref-store: don't add newline to reflog message

- The files backend produces a newline for messages automatically, so before we
- would print blank lines between entries.
+ By convention, reflog messages always end in '\n', so
+ before we would print blank lines between entries.

 3:  0319503045b = 3:  46a8e13a5e6 t1405: check for_each_reflog_ent_reverse() more thoroughly
 4:  62f5cb8a824 ! 4:  40ba92dbf0d test-ref-store: tweaks to for-each-reflog-ent format
     @@ t/t1400-update-ref.sh: $A $B $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 11171502
      -	test_when_finished "rm -rf .git/$m .git/logs expect" &&
      -	test_cmp expect .git/logs/$m
      +	test_when_finished "git update-ref -d $m && rm -rf .git/logs actual expect" &&
     -+	test-tool ref-store main for-each-reflog-ent $m > actual &&
     ++	test-tool ref-store main for-each-reflog-ent $m >actual &&
      +	test_cmp actual expect
       '
       
     @@ t/t1400-update-ref.sh: $A $B $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 11171503
      -	test_when_finished "rm -f .git/$m .git/logs/$m expect" &&
      -	test_cmp expect .git/logs/$m
      +	test_when_finished "git update-ref -d $m && rm -rf .git/logs actual expect" &&
     -+	test-tool ref-store main for-each-reflog-ent $m > actual &&
     ++	test-tool ref-store main for-each-reflog-ent $m >actual &&
      +	test_cmp actual expect
       '

5: 0288e743eb2 ! 5: 751f713a025 refs/debug: trim trailing LF from reflog message

     @@ refs/debug.c: static int debug_print_reflog_ent(struct object_id *old_oid,
       	int ret;
       	char o[GIT_MAX_HEXSZ + 1] = "null";
       	char n[GIT_MAX_HEXSZ + 1] = "null";
     -+	struct strbuf trimmed = STRBUF_INIT;
     ++	char *msgend = strchrnul(msg, '\n');
       	if (old_oid)
       		oid_to_hex_r(o, old_oid);
       	if (new_oid)
     - 		oid_to_hex_r(n, new_oid);
     +@@ refs/debug.c: static int debug_print_reflog_ent(struct object_id *old_oid,
       
     -+	strbuf_addstr(&trimmed, msg);
       	ret = dbg->fn(old_oid, new_oid, committer, timestamp, tz, msg,
       		      dbg->cb_data);
      -	trace_printf_key(&trace_refs, "reflog_ent %s (ret %d): %s -> %s, %s %ld \"%s\"\n",
      -		dbg->refname, ret, o, n, committer, (long int)timestamp, msg);
     -+	strbuf_trim_trailing_newline(&trimmed);
      +	trace_printf_key(&trace_refs,
     -+			 "reflog_ent %s (ret %d): %s -> %s, %s %ld \"%s\"\n",
     ++			 "reflog_ent %s (ret %d): %s -> %s, %s %ld \"%.*s\"\n",
      +			 dbg->refname, ret, o, n, committer,
     -+			 (long int)timestamp, trimmed.buf);
     -+	strbuf_release(&trimmed);
     ++			 (long int)timestamp, (int)(msgend - msg), msg);
       	return ret;
       }

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