cat-file: add mailmap subcommand to --batch-command
git-cat-file(1)'s --batch-command works with the --use-mailmap option, but this option needs to be set when the process is created. This means we cannot change this option mid-operation. At GitLab, Gitaly keeps interacting with a long-lived git-cat-file process and it would be useful if --batch-command supported toggling mailmap dynamically on an existing process. Add a `mailmap` subcommand to --batch-command that takes a boolean argument (usual ways you can specify a boolean value like 'yes', 'true', etc., are supported). Mailmap data is loaded lazily and kept in memory, while a helper centralizes the one-time load path used both at startup and from the batch-command handler. Extend tests to cover runtime toggling, startup option interactions (`--mailmap`/`--no-mailmap`), accepted boolean forms, and invalid values. Signed-off-by: Siddharth Asthana <siddharthasthana31@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Siddharth Asthana committed
Apr 16, 2026 at 09:02 UTC
6da647d8522641f932528de0167413719a38a2c0
3 files changed
+143
-4
Documentation/git-cat-file.adoc
+5
@@ -174,6 +174,11 @@ flush::
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since the beginning or since the last flush was issued. When `--buffer`
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is used, no output will come until a `flush` is issued. When `--buffer`
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is not used, commands are flushed each time without issuing `flush`.
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+
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+`mailmap (<bool>)`::
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+ Enable or disable mailmap for subsequent commands. The `<bool>`
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+ argument accepts the same boolean values as linkgit:git-config[1].
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+ The mailmap data is read upon the first use and only once.
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--
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+
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builtin/cat-file.c
+33
-4
@@ -57,6 +57,20 @@ static int use_mailmap;
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static char *replace_idents_using_mailmap(char *, size_t *);
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+/*
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+ * The mailmap is initialized with .strdup_strings set to 0,
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+ * but read_mailmap() sets the bit to 1 (this is true even when
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+ * not a single mailmap entry is read), so it can be used for
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+ * lazy loading.
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+ */
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+static void load_mailmap(void)
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+{
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+ if (mailmap.strdup_strings)
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+ return;
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+
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+ read_mailmap(the_repository, &mailmap);
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+}
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+
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static char *replace_idents_using_mailmap(char *object_buf, size_t *size)
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{
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struct strbuf sb = STRBUF_INIT;
@@ -692,6 +706,20 @@ static void parse_cmd_info(struct batch_options *opt,
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batch_one_object(line, output, opt, data);
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}
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+static void parse_cmd_mailmap(struct batch_options *opt UNUSED,
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+ const char *line,
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+ struct strbuf *output UNUSED,
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+ struct expand_data *data UNUSED)
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+{
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+ use_mailmap = git_parse_maybe_bool(line);
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+
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+ if (use_mailmap < 0)
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+ die(_("mailmap: invalid boolean '%s'"), line);
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+
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+ if (use_mailmap)
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+ load_mailmap();
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+}
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+
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static void dispatch_calls(struct batch_options *opt,
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struct strbuf *output,
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struct expand_data *data,
@@ -725,9 +753,10 @@ static const struct parse_cmd {
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parse_cmd_fn_t fn;
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unsigned takes_args;
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} commands[] = {
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- { "contents", parse_cmd_contents, 1},
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- { "info", parse_cmd_info, 1},
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- { "flush", NULL, 0},
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+ { "contents", parse_cmd_contents, 1 },
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+ { "info", parse_cmd_info, 1 },
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+ { "flush", NULL, 0 },
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+ { "mailmap", parse_cmd_mailmap, 1 },
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};
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static void batch_objects_command(struct batch_options *opt,
@@ -1128,7 +1157,7 @@ int cmd_cat_file(int argc,
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opt_epts = (opt == 'e' || opt == 'p' || opt == 't' || opt == 's');
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if (use_mailmap)
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- read_mailmap(the_repository, &mailmap);
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+ load_mailmap();
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switch (batch.objects_filter.choice) {
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case LOFC_DISABLED:
t/t4203-mailmap.sh
+105
@@ -1133,6 +1133,111 @@ test_expect_success 'git cat-file --batch-command returns correct size with --us
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test_cmp expect actual
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'
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+test_expect_success 'git cat-file --batch-command mailmap yes enables mailmap mid-stream' '
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+ test_when_finished "rm .mailmap" &&
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+ cat >.mailmap <<-\EOF &&
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+ C O Mitter <committer@example.com> Orig <orig@example.com>
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+ EOF
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+ commit_sha=$(git rev-parse HEAD) &&
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+ git cat-file commit HEAD >commit_no_mailmap.out &&
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+ git cat-file --use-mailmap commit HEAD >commit_mailmap.out &&
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+ size_no_mailmap=$(wc -c <commit_no_mailmap.out) &&
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+ size_mailmap=$(wc -c <commit_mailmap.out) &&
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+ printf "info HEAD\nmailmap yes\ninfo HEAD\n" | git cat-file --batch-command >actual &&
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+ echo $commit_sha commit $size_no_mailmap >expect &&
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+ echo $commit_sha commit $size_mailmap >>expect &&
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+ test_cmp expect actual
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+'
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+
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+test_expect_success 'git cat-file --batch-command mailmap no disables mailmap mid-stream' '
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+ test_when_finished "rm .mailmap" &&
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+ cat >.mailmap <<-\EOF &&
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+ C O Mitter <committer@example.com> Orig <orig@example.com>
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+ EOF
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+ commit_sha=$(git rev-parse HEAD) &&
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+ git cat-file commit HEAD >commit_no_mailmap.out &&
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+ git cat-file --use-mailmap commit HEAD >commit_mailmap.out &&
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+ size_no_mailmap=$(wc -c <commit_no_mailmap.out) &&
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+ size_mailmap=$(wc -c <commit_mailmap.out) &&
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+ printf "mailmap yes\ninfo HEAD\nmailmap no\ninfo HEAD\n" | git cat-file --batch-command >actual &&
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+ echo $commit_sha commit $size_mailmap >expect &&
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+ echo $commit_sha commit $size_no_mailmap >>expect &&
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+ test_cmp expect actual
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+'
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+
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+test_expect_success 'git cat-file --batch-command mailmap works in --buffer mode' '
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+ test_when_finished "rm .mailmap" &&
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+ cat >.mailmap <<-\EOF &&
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+ C O Mitter <committer@example.com> Orig <orig@example.com>
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+ EOF
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+ commit_sha=$(git rev-parse HEAD) &&
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+ git cat-file commit HEAD >commit_no_mailmap.out &&
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+ git cat-file --use-mailmap commit HEAD >commit_mailmap.out &&
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+ size_no_mailmap=$(wc -c <commit_no_mailmap.out) &&
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+ size_mailmap=$(wc -c <commit_mailmap.out) &&
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+ printf "mailmap yes\ninfo HEAD\nmailmap no\ninfo HEAD\nflush\n" | git cat-file --batch-command --buffer >actual &&
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+ echo $commit_sha commit $size_mailmap >expect &&
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+ echo $commit_sha commit $size_no_mailmap >>expect &&
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+ test_cmp expect actual
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+'
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+
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+test_expect_success 'git cat-file --batch-command mailmap no overrides startup --mailmap' '
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+ test_when_finished "rm .mailmap" &&
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+ cat >.mailmap <<-\EOF &&
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+ C O Mitter <committer@example.com> Orig <orig@example.com>
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+ EOF
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+ commit_sha=$(git rev-parse HEAD) &&
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+ git cat-file --use-mailmap commit HEAD >commit_mailmap.out &&
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+ size_mailmap=$(wc -c <commit_mailmap.out) &&
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+ git cat-file commit HEAD >commit_no_mailmap.out &&
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+ size_no_mailmap=$(wc -c <commit_no_mailmap.out) &&
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+ printf "info HEAD\nmailmap no\ninfo HEAD\n" | \
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+ git cat-file --mailmap --batch-command >actual &&
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+ echo $commit_sha commit $size_mailmap >expect &&
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+ echo $commit_sha commit $size_no_mailmap >>expect &&
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+ test_cmp expect actual
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+'
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+
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+test_expect_success 'git cat-file --batch-command mailmap yes overrides startup --no-mailmap' '
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+ test_when_finished "rm .mailmap" &&
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+ cat >.mailmap <<-\EOF &&
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+ C O Mitter <committer@example.com> Orig <orig@example.com>
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+ EOF
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+ commit_sha=$(git rev-parse HEAD) &&
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+ git cat-file commit HEAD >commit_no_mailmap.out &&
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+ size_no_mailmap=$(wc -c <commit_no_mailmap.out) &&
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+ git cat-file --use-mailmap commit HEAD >commit_mailmap.out &&
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+ size_mailmap=$(wc -c <commit_mailmap.out) &&
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+ printf "info HEAD\nmailmap yes\ninfo HEAD\n" | \
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+ git cat-file --no-mailmap --batch-command >actual &&
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+ echo $commit_sha commit $size_no_mailmap >expect &&
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+ echo $commit_sha commit $size_mailmap >>expect &&
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+ test_cmp expect actual
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+'
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+
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+test_expect_success 'git cat-file --batch-command mailmap accepts true/false' '
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+ test_when_finished "rm .mailmap" &&
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+ cat >.mailmap <<-\EOF &&
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+ C O Mitter <committer@example.com> Orig <orig@example.com>
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+ EOF
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+ commit_sha=$(git rev-parse HEAD) &&
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+ git cat-file commit HEAD >commit_no_mailmap.out &&
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+ size_no_mailmap=$(wc -c <commit_no_mailmap.out) &&
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+ git cat-file --use-mailmap commit HEAD >commit_mailmap.out &&
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+ size_mailmap=$(wc -c <commit_mailmap.out) &&
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+ printf "mailmap true\ninfo HEAD\nmailmap false\ninfo HEAD\n" | \
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+ git cat-file --batch-command >actual &&
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+ echo $commit_sha commit $size_mailmap >expect &&
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+ echo $commit_sha commit $size_no_mailmap >>expect &&
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+ test_cmp expect actual
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+'
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+
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+test_expect_success 'git cat-file --batch-command mailmap rejects invalid boolean' '
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+ echo "mailmap maybe" >in &&
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+ test_must_fail git cat-file --batch-command <in 2>err &&
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+ test_grep "mailmap: invalid boolean .*maybe" err
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+'
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+
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test_expect_success 'git cat-file --mailmap works with different author and committer' '
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test_when_finished "rm .mailmap" &&
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cat >.mailmap <<-\EOF &&