Re: [PATCH v2] Submodule: use the submodule repository to abbreviate commits

>
> From: Srujith A Poojary <poojarysrujith@gmail.com>
>
> The commit IDs shown in a submodule diff header belong to the
> submodule's object database. However, strbuf_add_unique_abbrev()
> uses the_repository, so it checks the superproject's object
> database when abbreviating those IDs.
>
> Use the submodule repository when it is available, and fall back
> to the repository from the diff options when it is not.
>
> Signed-off-by: Srujith A Poojary <poojarysrujith@gmail.com>
> ---
>     [Outreachy PATCH] t4041: use submodule repository for commit
>     abbreviations
>
> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-2288%2Fpoojarysrujith%2Fmicroproject-git-libification-v2
> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-2288/poojarysrujith/microproject-git-libification-v2
> Pull-Request: https://github.com/gitgitgadget/git/pull/2288
>
> Range-diff vs v1:
>
>  1:  7b2af1b46a ! 1:  3133cd3017 [Outreachy PATCH] t4041: use submodule repository for commit abbreviations
>      @@ Metadata
>       Author: Srujith A Poojary <poojarysrujith@gmail.com>
>
>        ## Commit message ##
>      -    [Outreachy PATCH] t4041: use submodule repository for commit abbreviations
>      +    Submodule: use the submodule repository to abbreviate commits
>
>      -    Use the submodule repository when abbreviating commit IDs in
>      -    submodule diff headers, so uniqueness is checked against the
>      -    correct object database.
>      +    The commit IDs shown in a submodule diff header belong to the
>      +    submodule's object database. However, strbuf_add_unique_abbrev()
>      +    uses the_repository, so it checks the superproject's object
>      +    database when abbreviating those IDs.
>      +
>      +    Use the submodule repository when it is available, and fall back
>      +    to the repository from the diff options when it is not.
>
>           Signed-off-by: Srujith A Poojary <poojarysrujith@gmail.com>
>
>        ## submodule.c ##
>       @@ submodule.c: 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;
>      +@@ submodule.c: 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);
>      -+ if (sub)
>      -+         strbuf_repo_add_unique_abbrev(&sb, sub, one, DEFAULT_ABBREV);
>      -+ else
>      -+         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);
>      -+ if (sub)
>      -+         strbuf_repo_add_unique_abbrev(&sb, sub, two, DEFAULT_ABBREV);
>      -+ else
>      -+         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
>
>
>  submodule.c                      |  5 +++--
>  t/t4041-diff-submodule-option.sh | 18 ++++++++++++++++++
>  2 files changed, 21 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..e80472af32 100755
> --- a/t/t4041-diff-submodule-option.sh
> +++ b/t/t4041-diff-submodule-option.sh
> @@ -14,6 +14,24 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
>
>  . ./test-lib.sh
>
> +test_expect_success SHA1 'submodule commit abbreviation uses submodule object database' '
> +       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 0000000000e..%s:\n  > child\n" \
> +               "$(git -C collision-super/sm1 rev-parse --short "$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
> --
> gitgitgadget
>