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

From
Patrick Steinhardt <ps@pks.im>
Date
Apr 19, 2024, 09:51 UTC
Message-ID
<9cb7baa50c6df77adfc2017a16883b3cb0c587e2.1713519789.git.ps@pks.im>
In-Reply-To
<cover.1713519789.git.ps@pks.im>

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 <ps@pks.im>
---
 builtin/rev-parse.c  | 5 ++---
 t/t1500-rev-parse.sh | 6 ++++++
 2 files changed, 8 insertions(+), 3 deletions(-)
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
-- 
2.44.GIT
Previous: Patrick SteinhardtNext: Patrick Steinhardt
Message 14 of 67 in “Stop relying on SHA1 fallback for `the_hash_algo`”
  1. 00/11 Stop relying on SHA1 fallback for `the_hash_algo`Patrick Steinhardt, Apr 19, 2024
  2. 01/11 path: harden validation of HEAD with non-standard hashesPatrick Steinhardt, Apr 19, 2024
  3. brian m. carlsonApr 19, 2024
  4. Patrick SteinhardtApr 22, 2024
  5. Junio C HamanoApr 22, 2024
  6. Patrick SteinhardtApr 23, 2024
  7. Junio C HamanoApr 23, 2024
  8. 02/11 parse-options-cb: only abbreviate hashes when hash algo is knownPatrick Steinhardt, Apr 19, 2024
  9. Justin ToblerApr 23, 2024
  10. 03/11 attr: don't recompute default attribute sourcePatrick Steinhardt, Apr 19, 2024
  11. Justin ToblerApr 23, 2024
  12. 04/11 attr: fix BUG() when parsing attrs outside of repoPatrick Steinhardt, Apr 19, 2024
  13. 05/11 remote-curl: fix parsing of detached SHA256 headsPatrick Steinhardt, Apr 19, 2024
  14. 06/11 builtin/rev-parse: allow shortening to more than 40 hex charactersPatrick Steinhardt, Apr 19, 2024
  15. 07/11 builtin/blame: don't access potentially unitialized `the_hash_algo`Patrick Steinhardt, Apr 19, 2024
  16. 08/11 builtin/bundle: abort "verify" early when there is no repositoryPatrick Steinhardt, Apr 19, 2024
  17. 09/11 builtin/diff: explicitly set hash algo when there is no repoPatrick Steinhardt, Apr 19, 2024
  18. Junio C HamanoApr 22, 2024
  19. 10/11 builtin/shortlog: don't set up revisions without repoPatrick Steinhardt, Apr 19, 2024
  20. Justin ToblerApr 23, 2024
  21. 11/11 repository: stop setting SHA1 as the default object hashPatrick Steinhardt, Apr 19, 2024
  22. brian m. carlsonApr 19, 2024
  23. Junio C HamanoApr 19, 2024
  24. Patrick SteinhardtApr 22, 2024
  25. 00/12 Stop relying on SHA1 fallback for `the_hash_algo`Patrick Steinhardt, Apr 23, 2024
  26. 01/12 path: harden validation of HEAD with non-standard hashesPatrick Steinhardt, Apr 23, 2024
  27. 02/12 path: move `validate_headref()` to its only userPatrick Steinhardt, Apr 23, 2024
  28. 03/12 parse-options-cb: only abbreviate hashes when hash algo is knownPatrick Steinhardt, Apr 23, 2024
  29. 04/12 attr: don't recompute default attribute sourcePatrick Steinhardt, Apr 23, 2024
  30. 05/12 attr: fix BUG() when parsing attrs outside of repoPatrick Steinhardt, Apr 23, 2024
  31. 06/12 remote-curl: fix parsing of detached SHA256 headsPatrick Steinhardt, Apr 23, 2024
  32. 07/12 builtin/rev-parse: allow shortening to more than 40 hex charactersPatrick Steinhardt, Apr 23, 2024
  33. 08/12 builtin/blame: don't access potentially unitialized `the_hash_algo`Patrick Steinhardt, Apr 23, 2024
  34. 09/12 builtin/bundle: abort "verify" early when there is no repositoryPatrick Steinhardt, Apr 23, 2024
  35. 10/12 builtin/diff: explicitly set hash algo when there is no repoPatrick Steinhardt, Apr 23, 2024
  36. 11/12 builtin/shortlog: don't set up revisions without repoPatrick Steinhardt, Apr 23, 2024
  37. 12/12 repository: stop setting SHA1 as the default object hashPatrick Steinhardt, Apr 23, 2024
  38. Junio C HamanoApr 27, 2024
  39. Patrick SteinhardtApr 29, 2024
  40. 00/13 Stop relying on SHA1 fallback for `the_hash_algo`Patrick Steinhardt, Apr 29, 2024
  41. 01/13 path: harden validation of HEAD with non-standard hashesPatrick Steinhardt, Apr 29, 2024
  42. 02/13 path: move `validate_headref()` to its only userPatrick Steinhardt, Apr 29, 2024
  43. 03/13 parse-options-cb: only abbreviate hashes when hash algo is knownPatrick Steinhardt, Apr 29, 2024
  44. 04/13 attr: don't recompute default attribute sourcePatrick Steinhardt, Apr 29, 2024
  45. 05/13 attr: fix BUG() when parsing attrs outside of repoPatrick Steinhardt, Apr 29, 2024
  46. 06/13 remote-curl: fix parsing of detached SHA256 headsPatrick Steinhardt, Apr 29, 2024
  47. 07/13 builtin/rev-parse: allow shortening to more than 40 hex charactersPatrick Steinhardt, Apr 29, 2024
  48. 08/13 builtin/blame: don't access potentially unitialized `the_hash_algo`Patrick Steinhardt, Apr 29, 2024
  49. 09/13 builtin/bundle: abort "verify" early when there is no repositoryPatrick Steinhardt, Apr 29, 2024
  50. 10/13 builtin/diff: explicitly set hash algo when there is no repoPatrick Steinhardt, Apr 29, 2024
  51. 11/13 builtin/shortlog: don't set up revisions without repoPatrick Steinhardt, Apr 29, 2024
  52. 12/13 oss-fuzz/commit-graph: set up hash algorithmPatrick Steinhardt, Apr 29, 2024
  53. 13/13 repository: stop setting SHA1 as the default object hashPatrick Steinhardt, Apr 29, 2024
  54. 00/13 Stop relying on SHA1 fallback for `the_hash_algo`Patrick Steinhardt, May 7, 2024
  55. 01/13 path: harden validation of HEAD with non-standard hashesPatrick Steinhardt, May 7, 2024
  56. 02/13 path: move `validate_headref()` to its only userPatrick Steinhardt, May 7, 2024
  57. 03/13 parse-options-cb: only abbreviate hashes when hash algo is knownPatrick Steinhardt, May 7, 2024
  58. 04/13 attr: don't recompute default attribute sourcePatrick Steinhardt, May 7, 2024
  59. 05/13 attr: fix BUG() when parsing attrs outside of repoPatrick Steinhardt, May 7, 2024
  60. 06/13 remote-curl: fix parsing of detached SHA256 headsPatrick Steinhardt, May 7, 2024
  61. 07/13 builtin/rev-parse: allow shortening to more than 40 hex charactersPatrick Steinhardt, May 7, 2024
  62. 08/13 builtin/blame: don't access potentially unitialized `the_hash_algo`Patrick Steinhardt, May 7, 2024
  63. 09/13 builtin/bundle: abort "verify" early when there is no repositoryPatrick Steinhardt, May 7, 2024
  64. 10/13 builtin/diff: explicitly set hash algo when there is no repoPatrick Steinhardt, May 7, 2024
  65. 11/13 builtin/shortlog: don't set up revisions without repoPatrick Steinhardt, May 7, 2024
  66. 12/13 oss-fuzz/commit-graph: set up hash algorithmPatrick Steinhardt, May 7, 2024
  67. 13/13 repository: stop setting SHA1 as the default object hashPatrick Steinhardt, May 7, 2024

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