[06/11] builtin/rev-parse: allow shortening to more than 40 hex characters

Commit Message

Patrick Steinhardt April 19, 2024, 9:51 a.m. UTC

The `--short=` option for git-rev-parse(1) allows the user to specify
to how many characters object IDs should be shortened to. The option is
broken though for SHA256 repositories because we set the maximum allowed
hash size to `the_hash_algo->hexsz` before we have even set up the repo.
Consequently, `the_hash_algo` will always be SHA1 and thus we truncate
every hash after at most 40 characters.

Fix this by accessing `the_hash_algo` only after we have set up the
repo.

Signed-off-by: Patrick Steinhardt <[e-mail]>
---
 builtin/rev-parse.c  | 5 ++---
 t/t1500-rev-parse.sh | 6 ++++++
 2 files changed, 8 insertions(+), 3 deletions(-)

Patch

diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
index 624182e507..d7b87c605e 100644
--- a/builtin/rev-parse.c
+++ b/builtin/rev-parse.c
@@ -687,7 +687,6 @@  int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 	const char *name = NULL;
 	struct object_context unused;
 	struct strbuf buf = STRBUF_INIT;
-	const int hexsz = the_hash_algo->hexsz;
 	int seen_end_of_options = 0;
 	enum format_type format = FORMAT_DEFAULT;
 
@@ -863,8 +862,8 @@  int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 				abbrev = strtoul(arg, NULL, 10);
 				if (abbrev < MINIMUM_ABBREV)
 					abbrev = MINIMUM_ABBREV;
-				else if (hexsz <= abbrev)
-					abbrev = hexsz;
+				else if ((int)the_hash_algo->hexsz <= abbrev)
+					abbrev = the_hash_algo->hexsz;
 				continue;
 			}
 			if (!strcmp(arg, "--sq")) {
diff --git a/t/t1500-rev-parse.sh b/t/t1500-rev-parse.sh
index a669e592f1..30c31918fd 100755
--- a/t/t1500-rev-parse.sh
+++ b/t/t1500-rev-parse.sh
@@ -304,4 +304,10 @@  test_expect_success 'rev-parse --bisect includes bad, excludes good' '
 	test_cmp expect actual
 '
 
+test_expect_success '--short= truncates to the actual hash length' '
+	git rev-parse HEAD >expect &&
+	git rev-parse --short=100 HEAD >actual &&
+	test_cmp expect actual
+'
+
 test_done