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[PATCH v4 4/5] builtin/hash-object: fix uninitialized hash function

From
Junio C Hamano <gitster@pobox.com>
Date
May 14, 2024, 01:14 UTC
Message-ID
<20240514011437.3779151-5-gitster@pobox.com>
In-Reply-To
<20240514011437.3779151-1-gitster@pobox.com>
From: Patrick Steinhardt <ps@pks.im>

The git-hash-object(1) command allows users to hash an object even without a repository. Starting with c8aed5e8da (repository: stop setting SHA1 as the default object hash, 2024-05-07), this will make us hit an uninitialized hash function, which subsequently leads to a segfault.

Fix this by falling back to SHA-1 explicitly when running outside of a Git repository. Users can use GIT_DEFAULT_HASH environment to specify what hash algorithm they want, so arguably this code should not be needed.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 builtin/hash-object.c   | 3 +++
 t/t1007-hash-object.sh  | 6 ++++++
 t/t1517-outside-repo.sh | 2 +-
 3 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/builtin/hash-object.c b/builtin/hash-object.c
index 82ca6d2bfd..c767414a0c 100644
--- a/builtin/hash-object.c
+++ b/builtin/hash-object.c
@@ -123,6 +123,9 @@ int cmd_hash_object(int argc, const char **argv, const char *prefix)
 	else
 		prefix = setup_git_directory_gently(&nongit);
 
+	if (nongit && !the_hash_algo)
+		repo_set_hash_algo(the_repository, GIT_HASH_SHA1);
+
 	if (vpath && prefix) {
 		vpath_free = prefix_filename(prefix, vpath);
 		vpath = vpath_free;
diff --git a/t/t1007-hash-object.sh b/t/t1007-hash-object.sh
index 64aea38486..4c138c6ca4 100755
--- a/t/t1007-hash-object.sh
+++ b/t/t1007-hash-object.sh
@@ -260,4 +260,10 @@ test_expect_success '--literally with extra-long type' '
 	echo example | git hash-object -t $t --literally --stdin
 '
 
+test_expect_success '--stdin outside of repository' '
+	nongit git hash-object --stdin <hello >actual &&
+	echo "$(test_oid hello)" >expect &&
+	test_cmp expect actual
+'
+
 test_done
diff --git a/t/t1517-outside-repo.sh b/t/t1517-outside-repo.sh
index ac5f3191cc..854bb8f343 100755
--- a/t/t1517-outside-repo.sh
+++ b/t/t1517-outside-repo.sh
@@ -30,7 +30,7 @@ test_expect_success 'compute a patch-id outside repository' '
 	test_cmp patch-id.expect patch-id.actual
 '
 
-test_expect_failure 'hash-object outside repository' '
+test_expect_success 'hash-object outside repository' '
 	git hash-object --stdin <sample.patch >hash.expect &&
 	(
 		cd non-repo &&
-- 
2.45.0-145-g3e4a232f6e
Previous: Junio C HamanoNext: Junio C Hamano
Message 45 of 62 in “Fix use of uninitialized hash algos”
  1. 0/2 Fix use of uninitialized hash algosPatrick Steinhardt, May 13, 2024
  2. 1/2 builtin/patch-id: fix uninitialized hash functionPatrick Steinhardt, May 13, 2024
  3. 2/2 builtin/hash-object: fix uninitialized hash functionPatrick Steinhardt, May 13, 2024
  4. Junio C HamanoMay 14, 2024
  5. Junio C HamanoMay 13, 2024
  6. Junio C HamanoMay 13, 2024
  7. 0/4 Fix use of uninitialized hash algorithmsJunio C Hamano, May 13, 2024
  8. 1/4 setup: add an escape hatch for "no more default hash algorithm" changeJunio C Hamano, May 13, 2024
  9. Kyle LippincottMay 13, 2024
  10. 2/4 t1517: test commands that are designed to be run outside repositoryJunio C Hamano, May 13, 2024
  11. Kyle LippincottMay 13, 2024
  12. Junio C HamanoMay 13, 2024
  13. Junio C HamanoMay 13, 2024
  14. Kyle LippincottMay 13, 2024
  15. 3/4 builtin/patch-id: fix uninitialized hash functionJunio C Hamano, May 13, 2024
  16. 4/4 builtin/hash-object: fix uninitialized hash functionJunio C Hamano, May 13, 2024
  17. 5/4 apply: fix uninitialized hash functionJunio C Hamano, May 13, 2024
  18. 0/5 Fix use of uninitialized hash algorithmsJunio C Hamano, May 13, 2024
  19. 1/5 setup: add an escape hatch for "no more default hash algorithm" changeJunio C Hamano, May 13, 2024
  20. 2/5 t1517: test commands that are designed to be run outside repositoryJunio C Hamano, May 13, 2024
  21. 3/5 builtin/patch-id: fix uninitialized hash functionJunio C Hamano, May 13, 2024
  22. Junio C HamanoMay 13, 2024
  23. Patrick SteinhardtMay 14, 2024
  24. Junio C HamanoMay 14, 2024
  25. 4/5 builtin/hash-object: fix uninitialized hash functionJunio C Hamano, May 13, 2024
  26. Junio C HamanoMay 13, 2024
  27. Patrick SteinhardtMay 14, 2024
  28. Junio C HamanoMay 14, 2024
  29. 5/5 apply: fix uninitialized hash functionJunio C Hamano, May 13, 2024
  30. 0/5 Fix use of uninitialized hash algorithmsJunio C Hamano, May 14, 2024
  31. 1/5 setup: add an escape hatch for "no more default hash algorithm" changeJunio C Hamano, May 14, 2024
  32. Patrick SteinhardtMay 14, 2024
  33. Junio C HamanoMay 14, 2024
  34. Junio C HamanoMay 14, 2024
  35. Patrick SteinhardtMay 15, 2024
  36. Junio C HamanoMay 16, 2024
  37. 2/5 t1517: test commands that are designed to be run outside repositoryJunio C Hamano, May 14, 2024
  38. Patrick SteinhardtMay 14, 2024
  39. Junio C HamanoMay 14, 2024
  40. Patrick SteinhardtMay 15, 2024
  41. Junio C HamanoMay 15, 2024
  42. Patrick SteinhardtMay 15, 2024
  43. Junio C HamanoMay 15, 2024
  44. 3/5 builtin/patch-id: fix uninitialized hash functionJunio C Hamano, May 14, 2024
  45. 4/5 builtin/hash-object: fix uninitialized hash functionJunio C Hamano, May 14, 2024
  46. Junio C HamanoMay 17, 2024
  47. Junio C HamanoMay 20, 2024
  48. Junio C HamanoMay 20, 2024
  49. 5/5 apply: fix uninitialized hash functionJunio C Hamano, May 14, 2024
  50. 0/5 Fix use of uninitialized hash algorithmsJunio C Hamano, May 20, 2024
  51. 1/5 setup: add an escape hatch for "no more default hash algorithm" changeJunio C Hamano, May 20, 2024
  52. Patrick SteinhardtMay 21, 2024
  53. Junio C HamanoMay 21, 2024
  54. 2/5 t1517: test commands that are designed to be run outside repositoryJunio C Hamano, May 20, 2024
  55. 3/5 builtin/patch-id: fix uninitialized hash functionJunio C Hamano, May 20, 2024
  56. 4/5 builtin/hash-object: fix uninitialized hash functionJunio C Hamano, May 20, 2024
  57. 5/5 apply: fix uninitialized hash functionJunio C Hamano, May 20, 2024
  58. Patrick SteinhardtMay 21, 2024
  59. Junio C HamanoMay 21, 2024
  60. Patrick SteinhardtMay 21, 2024
  61. Junio C HamanoMay 21, 2024
  62. Patrick SteinhardtMay 22, 2024

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