[PATCH v6] submodule: use the submodule repository to abbreviate commits

From

SGSrujith A Poojary via GitGitGadget <gitgitgadget@gmail.com>

Date

Nov 4, 2026, 19:45 UTC

Message-ID

<pull.2288.v6.git.1793821554097.gitgitgadget@gmail.com>

In-Reply-To

<pull.2288.git.1793435149942.gitgitgadget@gmail.com>

From: Srujith A Poojary <poojarysrujith@gmail.com>

Signed-off-by: Srujith A Poojary <poojarysrujith@gmail.com>
---
    [Outreachy PATCH] t4041: use submodule repository for commit
    abbreviations
    
    Changes since v4:
    
     * Combine the implementation and SHA-256 test updates into a single
       patch.
     * Update the commit message to explain how the test uses test_oid to
       switch expectations between SHA-1 and SHA-256 repositories.

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-2288%2Fpoojarysrujith%2Fmicroproject-git-libification-v6
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-2288/poojarysrujith/microproject-git-libification-v6
Pull-Request: https://github.com/gitgitgadget/git/pull/2288

Range-diff vs v5:

 1:  f94aa2476f ! 1:  01c3cc2573 submodule: use the submodule repository to abbreviate commits
     @@ Commit message
          Use the submodule repository when it is available, and fall back
          to the repository from the diff options when it is not.
      
     -    The expected abbreviation for a submodule commit depends on the
     -    repository's hash algorithm. Use test_oid_cache to provide the
     -    expected value for each algorithm and remove the SHA1 prerequisite
     -    so this test runs with both SHA-1 and SHA-256.
     +    As the expected abbreviation depends on the hash algorithm used,
     +    the test uses the test_oid mechanism to switch the expectation
     +    between SHA-1 and SHA-256 repositories.
      
          Signed-off-by: Srujith A Poojary <poojarysrujith@gmail.com>
      

 submodule.c                      |  5 +++--
 t/t4041-diff-submodule-option.sh | 23 +++++++++++++++++++++++
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/submodule.c b/submodule.c
index 6fcb606f7e..1302c11ddf 100644
--- a/submodule.c
+++ b/submodule.c
@@ -543,6 +543,7 @@ static void show_submodule_header(struct diff_options *o,
 		struct commit **left, struct commit **right,
 		struct commit_list **merge_bases)
 {
+	struct repository *repo = sub ? sub : o->repo;
 	const char *message = NULL;
 	struct strbuf sb = STRBUF_INIT;
 	int fast_forward = 0, fast_backward = 0;
@@ -599,9 +600,9 @@ static void show_submodule_header(struct diff_options *o,
 
 output_header:
 	strbuf_addf(&sb, "Submodule %s ", path);
-	strbuf_add_unique_abbrev(&sb, one, DEFAULT_ABBREV);
+	strbuf_repo_add_unique_abbrev(&sb, repo, one, DEFAULT_ABBREV);
 	strbuf_addstr(&sb, (fast_backward || fast_forward) ? ".." : "...");
-	strbuf_add_unique_abbrev(&sb, two, DEFAULT_ABBREV);
+	strbuf_repo_add_unique_abbrev(&sb, repo, two, DEFAULT_ABBREV);
 	if (message)
 		strbuf_addf(&sb, " %s\n", message);
 	else
diff --git a/t/t4041-diff-submodule-option.sh b/t/t4041-diff-submodule-option.sh
index 4dd4954260..4539d6bba5 100755
--- a/t/t4041-diff-submodule-option.sh
+++ b/t/t4041-diff-submodule-option.sh
@@ -14,6 +14,29 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
 . ./test-lib.sh
 
+test_expect_success 'submodule commit abbreviation uses submodule object database' '
+	test_oid_cache <<-EOF &&
+	submodule_commit1_abbrev sha1:0000000000e
+	submodule_commit1_abbrev sha256:24c81a5
+	EOF
+	test_when_finished "rm -rf collision-super" &&
+	git init -q collision-super &&
+	git init -q collision-super/sm1 &&
+	printf "0\n1\n2\n3\n4\n5\n6\n7\n8\n9\n\nb1rwzyc3\n" >collision-super/sm1/a0blgqsjc &&
+	git -C collision-super/sm1 add a0blgqsjc &&
+	tree=$(git -C collision-super/sm1 write-tree) &&
+	commit1=$(GIT_AUTHOR_DATE="1112911993 -0700" GIT_COMMITTER_DATE="1112911993 -0700" git -C collision-super/sm1 commit-tree "$tree" -m a2onsxbvj) &&
+	commit2=$(printf "child\n" | GIT_AUTHOR_DATE="1112912053 -0700" GIT_COMMITTER_DATE="1112912053 -0700" git -C collision-super/sm1 commit-tree "$tree" -p "$commit1") &&
+	git -C collision-super/sm1 checkout -q "$commit2" &&
+	git -C collision-super update-index --add --cacheinfo 160000,"$commit1",sm1 &&
+	git -C collision-super commit -q -m "Add submodule" &&
+	git -C collision-super diff --submodule=log >actual &&
+	printf "Submodule sm1 %s..%s:\n  > child\n" \
+		"$(test_oid submodule_commit1_abbrev)" \
+		"$(git -C collision-super/sm1 rev-parse --short "$commit2")" >expected &&
+	test_cmp expected actual
+'
+
 # Test non-UTF-8 encoding in case iconv is available.
 if test_have_prereq ICONV
 then

base-commit: 50fe5cc63f9cd6e89b87a2c9ccf96a444f4cfdb7

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