[PATCH v2 0/2] commit: allow -m/-F/-c/-C for all --fixup variations
- From
- erik@cervined.in <erik@cervined.in>
- Date
- May 26, 2026, 10:47 UTC
- Message-ID
- <cover.1779792311.git.erik@cervined.in>
- In-Reply-To
- <20260518112225.73172-2-erik@cervined.in>
From: Erik Cervin-Edin <erik@cervined.in>
V1 was a single patch and only addressed -m/-F. V2 makes two substantive changes.
First, the refactor. V1 added a special-cased file slurp in cmd_commit() that pretended -F had been spelled -m. Junio noted this loses the "this came from a file" origin if anything goes wrong later in the control flow [1], and Phillip suggested refactoring prepare_to_commit() [2]. V2 does that: prepare_to_commit() now consults fixup_message at each message-source branch and routes the message origin flags through the same code path for all --fixup variations.
Second, scope extended to -c/-C. In the V1 thread I noted [3] that -F made sense across all --fixup variants for consistency, but that -c/-C felt "probably less justifiable" for plain --fixup. Looking at it more while refactoring, the existing patchwork of which flag works with which variant looked less and less like a design and more like an accident -- once -F was threaded through prepare_to_commit(), -c/-C fell out of the same path naturally (blocked by the same die_for_incompatible_opt4() grouping that caught -F). This lives in its own patch (2/2) -- I won't object if reviewers prefer to drop it or rolling it separately.
There is one wrinkle worth flagging on 2/2. When -c/-C names a source commit whose message starts with "amend! ", prepare_amend_commit() strips that line -- the same stripping that happens for a no-source --fixup=amend:<commit>. This is independent of which --fixup variant is being produced (the target); it depends only on whether the -c/-C source is itself an amend!/reword! commit. The upside is that
git commit --fixup=amend:foo -C foo
and
GIT_EDITOR=: git commit --fixup=amend:foo
produce the same commit. If reviewers would rather -c/-C take the source message verbatim, that's a small change and I'm open to it.
Smaller fixes from V1 review:
* "unusable" softened to "poorly suited" in the rationale [1].
* Dropped the incorrect claim that plain --fixup -m is
"practically a no-op" * Adopted Phillip's suggestion to use test_commit_message in the
new --fixup=amend: -m test, which also resolves the
expected/expect golden-file naming Junio called out [1][2].[1] https://lore.kernel.org/git/xmqqik8kc2nj.fsf@gitster.g/ [2] https://lore.kernel.org/git/ac6aaaca-2b7c-4892-ba93-0dc3e3c18ff7@gmail.com/ [3] https://lore.kernel.org/git/aguM7UIbAo19Zojv@mbp/
Erik Cervin-Edin (2): commit: allow -m/-F for all kinds of --fixup commit: allow -c/-C for all kinds of --fixup
Documentation/git-commit.adoc | 22 +++-- builtin/commit.c | 41 ++++---- t/t7500-commit-template-squash-signoff.sh | 114 +++++++++++++++++++--- 3 files changed, 133 insertions(+), 44 deletions(-)
Range-diff against v1:
1: 49e202f04b ! 1: e9f07d49ee commit: allow -m/-F with --fixup=amend: or reword:
@@ Metadata
Author: Erik Cervin-Edin <erik@cervined.in>
## Commit message ##
- commit: allow -m/-F with --fixup=amend: or reword:
+ commit: allow -m/-F for all kinds of --fixup
- commit: allow -m/-F with --fixup=amend: or reword:
+ The ability to provide a commit message for git commit --fixup and its
+ variations is limited:
- --fixup=amend: and --fixup=reword: require an editor to supply the
- replacement commit message. The -m and -F flags are rejected: -m is
- caught by a die() in prepare_to_commit(), and -F is caught by
+ * Plain --fixup only allows using the -m flag
+
+ * The amend/reword --fixup variants only allow supplying the message
+ using an editor
+
+ For amend/reword, the -m and -F flags are rejected: -m is caught by a
+ die() in prepare_to_commit(), and -F is caught by
die_for_incompatible_opt4() which groups -F with --fixup as mutually
- exclusive. This makes these modes unusable in non-interactive
- workflows -- notably AI coding agents.
+ exclusive. This makes these modes poorly suited for non-interactive
+ workflows -- notably when using AI coding agents.
+
+ When support to use the -m option was introduced in [1] it was noted
+ that there could be support for other options but at the time the use
+ case was deemed too niche. Later, when the amend suboption was
+ introduced in [2] -m support for amend fixups was discussed but not
+ pursued, and -F was already caught by the higher-layer incompatibility
+ check grouping it with --fixup.
+
+ The rejections of these options hark back to when --fixup was
+ introduced in [3] and as noted in [1] -- there's nothing inherently
+ preventing support for them. The current patchwork of which flags
+ work with which --fixup variants has no strong logic to it, and
+ allowing all of them simplifies both the code and the interface.
- When the amend suboption was introduced in 494d314a05 (commit: add
- amend suboption to --fixup to create amend! commit, 2021-03-15),
- -m support for amend fixups was discussed but not pursued, and -F
- was already caught by the higher-layer incompatibility check grouping
- it with --fixup.
+ Allow -m and -F to supply the message body for all --fixup variations,
+ mirroring the flow of a regular commit. -c and -C, which are blocked
+ by the same incompatibility check, are handled in the next commit.
- Allow -m and -F to supply the replacement message body for amend and
- reword fixups. When provided, bypass the editor and directly use the
- user's message as the body, replacing the original commit's message. For
- -F, the file contents are read into the message strbuf and then handled
- identically to -m.
+ 1. 30884c9afc (commit: add support for --fixup <commit> -m"<extra
+ message>", 2017-12-22)
- Plain --fixup (without amend: or reword:) continues to reject -F but
- still accepts -m (even though it's practically a no-op).
+ 2. 494d314a05 (commit: add amend suboption to --fixup to create amend!
+ commit, 2021-03-15)
- Signed-off-by: Erik Cervin Edin <erik@cervined.in>
+ 3. d71b8ba7c9 (commit: --fixup option for use with rebase --autosquash,
+ 2010-11-02)
+
+ Helped-by: Junio C Hamano <gitster@pobox.com>
+ Suggested-by: Phillip Wood <phillip.wood123@gmail.com>
+ Signed-off-by: Erik Cervin-Edin <erik@cervined.in>
## Documentation/git-commit.adoc ##
-@@ Documentation/git-commit.adoc: commit, but the additional commentary will be thrown away once the
+@@ Documentation/git-commit.adoc: include::diff-context-options.adoc[]
+ The commit created by plain `--fixup=<commit>` has a title
+ composed of "fixup!" followed by the title of _<commit>_,
+ and is recognized specially by `git rebase --autosquash`. The `-m`
+-option may be used to supplement the log message of the created
+-commit, but the additional commentary will be thrown away once the
+-"fixup!" commit is squashed into _<commit>_ by
++or `-F` option may be used to supplement the log message
++of the created commit, but the additional commentary will be thrown
++away once the "fixup!" commit is squashed into _<commit>_ by
+ `git rebase --autosquash`.
+ +
The commit created by `--fixup=amend:<commit>` is similar but its
title is instead prefixed with "amend!". The log message of
_<commit>_ is copied into the log message of the "amend!" commit and
@@ Documentation/git-commit.adoc: commit, but the additional commentary will be thr
-log message to be empty unless `--allow-empty-message` is
-specified.
+opened in an editor so it can be refined. The replacement message may
-+also be supplied directly using `-m` or `-F`, bypassing the need to open
-+an editor. When `git rebase --autosquash` squashes the "amend!" commit
-+into _<commit>_, the log message of _<commit>_ is replaced by the
-+refined log message from the "amend!" commit. It is an error for the
-+"amend!" commit's log message to be empty unless `--allow-empty-message`
-+is specified.
++also be supplied directly using `-m` or `-F`, bypassing the
++need to open an editor. When `git rebase
++--autosquash` squashes the "amend!" commit into _<commit>_, the log
++message of _<commit>_ is replaced by the refined log message from the
++"amend!" commit. It is an error for the "amend!" commit's log message
++to be empty unless `--allow-empty-message` is specified.
+
`--fixup=reword:<commit>` is shorthand for `--fixup=amend:<commit>
--only`. It creates an "amend!" commit with only a log message
## builtin/commit.c ##
+@@ builtin/commit.c: static int prepare_to_commit(const char *index_file, const char *prefix,
+ if (have_option_m && !fixup_message) {
+ strbuf_addbuf(&sb, &message);
+ hook_arg1 = "message";
+- } else if (logfile && !strcmp(logfile, "-")) {
++ } else if (logfile && !fixup_message && !strcmp(logfile, "-")) {
+ if (isatty(0))
+ fprintf(stderr, _("(reading log message from standard input)\n"));
+ if (strbuf_read(&sb, 0, 0) < 0)
+ die_errno(_("could not read log from standard input"));
+ hook_arg1 = "message";
+- } else if (logfile) {
++ } else if (logfile && !fixup_message) {
+ if (strbuf_read_file(&sb, logfile, 0) < 0)
+ die_errno(_("could not read log file '%s'"),
+ logfile);
+ hook_arg1 = "message";
+- } else if (use_message) {
++ } else if (use_message && !fixup_message) {
+ const char *buffer;
+ buffer = strstr(use_message_buffer, "\n\n");
+ if (buffer)
@@ builtin/commit.c: static int prepare_to_commit(const char *index_file, const char *prefix,
hook_arg1 = "message";
@@ builtin/commit.c: static int prepare_to_commit(const char *index_file, const cha
- * incompatible with all the forms of `--fixup` and
- * have already errored out while parsing the `git commit`
- * options.
-+ * `-m` (and `-F`, converted to `-m` earlier for
-+ * amend/reword) appends the message body here.
-+ * `-c`/`-C` are still incompatible with all forms
-+ * of `--fixup`.
++ * Only `-m` and `-F` are handled here. `-c`/`-C` are
++ * incompatible with --fixup and have already errored out
++ * during option parsing.
*/
- if (have_option_m && !strcmp(fixup_prefix, "fixup"))
+- if (have_option_m && !strcmp(fixup_prefix, "fixup"))
++ if (have_option_m) {
strbuf_addbuf(&sb, &message);
-
- if (!strcmp(fixup_prefix, "amend")) {
- if (have_option_m)
+-
+- if (!strcmp(fixup_prefix, "amend")) {
+- if (have_option_m)
- die(_("options '%s' and '%s:%s' cannot be used together"), "-m", "--fixup", fixup_message);
-- prepare_amend_commit(commit, &sb, &ctx);
-+ strbuf_addbuf(&sb, &message);
-+ else
-+ prepare_amend_commit(commit, &sb, &ctx);
++ } else if (logfile && !strcmp(logfile, "-")) {
++ if (isatty(0))
++ fprintf(stderr, _("(reading log message from standard input)\n"));
++ if (strbuf_read(&sb, 0, 0) < 0)
++ die_errno(_("could not read log from standard input"));
++ } else if (logfile) {
++ if (strbuf_read_file(&sb, logfile, 0) < 0)
++ die_errno(_("could not read log file '%s'"), logfile);
++ } else if (!strcmp(fixup_prefix, "amend")) {
+ prepare_amend_commit(commit, &sb, &ctx);
}
} else if (!stat(git_path_merge_msg(the_repository), &statbuf)) {
- size_t merge_msg_start;
@@ builtin/commit.c: static int parse_and_validate_options(int argc, const char *argv[],
}
if (fixup_message && squash_message)
@@ builtin/commit.c: static int parse_and_validate_options(int argc, const char *ar
!!edit_message, "-c",
- !!logfile, "-F",
!!fixup_message, "--fixup");
-+ die_for_incompatible_opt3(!!use_message, "-C",
-+ !!edit_message, "-c",
-+ !!logfile, "-F");
die_for_incompatible_opt4(have_option_m, "-m",
!!edit_message, "-c",
- !!use_message, "-C",
-@@ builtin/commit.c: static int parse_and_validate_options(int argc, const char *argv[],
- }
- }
-
-+ if (logfile && fixup_message && !strcmp(fixup_prefix, "fixup"))
-+ die(_("options '%s' and '%s' cannot be used together"), "-F", "--fixup");
-+
- if (0 <= edit_flag)
- use_editor = edit_flag;
-
-@@ builtin/commit.c: int cmd_commit(int argc,
- argc = parse_and_validate_options(argc, argv, builtin_commit_options,
- builtin_commit_usage,
- prefix, current_head, &s);
-+
-+ if (logfile && fixup_message && !strcmp(fixup_prefix, "amend")) {
-+ if (!strcmp(logfile, "-")) {
-+ if (isatty(0))
-+ fprintf(stderr, _("(reading log message from standard input)\n"));
-+ if (strbuf_read(&message, 0, 0) < 0)
-+ die_errno(_("could not read log from standard input"));
-+ } else {
-+ if (strbuf_read_file(&message, logfile, 0) < 0)
-+ die_errno(_("could not read log file '%s'"), logfile);
-+ }
-+ strbuf_complete_line(&message);
-+ have_option_m = 1;
-+ FREE_AND_NULL(logfile);
-+ }
-+
- if (trailer_args.nr)
- trailer_config_init();
-
## t/t7500-commit-template-squash-signoff.sh ##
@@ t/t7500-commit-template-squash-signoff.sh: test_expect_success '--fixup=reword: ignores staged changes' '
@@ t/t7500-commit-template-squash-signoff.sh: test_expect_success '--fixup=reword:
'
-test_expect_success '--fixup=reword: error out with -m option' '
-+test_expect_success '--fixup=amend: with -m option' '
++test_expect_success 'commit --fixup=reword: works with -m' '
commit_for_rebase_autosquash_setup &&
- echo "fatal: options '\''-m'\'' and '\''--fixup:reword'\'' cannot be used together" >expect &&
- test_must_fail git commit --fixup=reword:HEAD~ -m "reword commit message" 2>actual &&
-+ cat >expect <<-EOF &&
-+ amend! $(git log -1 --format=%s HEAD~)
+- test_cmp expect actual
++ git commit --fixup=reword:HEAD~ -m "reword commit message" &&
++ test_commit_message HEAD <<-EOF
++ amend! $(git log -1 --format=%s HEAD~2)
+
-+ amend commit message
++ reword commit message
+ EOF
-+ git commit --fixup=amend:HEAD~ -m "amend commit message" &&
-+ get_commit_msg HEAD >actual &&
- test_cmp expect actual
'
-test_expect_success '--fixup=amend: error out with -m option' '
-+test_expect_success '--fixup=reword: with -m option' '
++test_expect_success 'commit --fixup=amend: works with -m' '
commit_for_rebase_autosquash_setup &&
- echo "fatal: options '\''-m'\'' and '\''--fixup:amend'\'' cannot be used together" >expect &&
- test_must_fail git commit --fixup=amend:HEAD~ -m "amend commit message" 2>actual &&
-+ cat >expect <<-EOF &&
-+ amend! $(git log -1 --format=%s HEAD~)
+- test_cmp expect actual
++ git commit --fixup=amend:HEAD~ -m "amend commit message" &&
++ test_commit_message HEAD <<-EOF
++ amend! $(git log -1 --format=%s HEAD~2)
+
-+ reword commit message
++ amend commit message
+ EOF
-+ git commit --fixup=reword:HEAD~ -m "reword commit message" &&
-+ get_commit_msg HEAD >actual &&
- test_cmp expect actual
'
+ test_expect_success 'consecutive amend! commits remove amend! line from commit msg body' '
@@ t/t7500-commit-template-squash-signoff.sh: test_expect_success 'deny to create amend! commit if its commit msg body is empt
test_cmp expected actual
'
-+test_expect_success '--fixup=amend: -m with empty message aborts' '
++test_expect_success 'deny to create amend! commit if -m is empty' '
+ commit_for_rebase_autosquash_setup &&
-+ test_must_fail git commit --fixup=amend:HEAD~ -m "" 2>err &&
-+ test_grep "empty commit message body" err
++ echo "Aborting commit due to empty commit message body." >expect &&
++ test_must_fail git commit --fixup=amend:HEAD~ -m "" 2>actual &&
++ test_cmp expect actual
+'
+
test_expect_success 'amend! commit allows empty commit msg body with --allow-empty-message' '
@@ t/t7500-commit-template-squash-signoff.sh: test_expect_success '--fixup=reword:
-test_expect_success '--fixup=reword: -F give error message' '
- echo "fatal: options '\''-F'\'' and '\''--fixup'\'' cannot be used together" >expect &&
- test_must_fail git commit --fixup=reword:HEAD~ -F msg 2>actual &&
-+test_expect_success '--fixup=reword: with -F option' '
-+ commit_for_rebase_autosquash_setup &&
-+ echo "message from file" >msgfile &&
-+ cat >expect <<-EOF &&
-+ amend! $(git log -1 --format=%s HEAD~)
-+
-+ message from file
-+ EOF
-+ git commit --fixup=reword:HEAD~ -F msgfile &&
-+ get_commit_msg HEAD >actual &&
- test_cmp expect actual
- '
-
-+test_expect_success '--fixup=amend: with -F option' '
+- test_cmp expect actual
++test_expect_success 'commit --fixup works with -F' '
+ commit_for_rebase_autosquash_setup &&
-+ echo "amend message from file" >msgfile &&
-+ cat >expect <<-EOF &&
-+ amend! $(git log -1 --format=%s HEAD~)
++ echo "message" >msgfile &&
++ git commit --fixup HEAD~ -F msgfile &&
++ test_commit_message HEAD <<-EOF
++ fixup! $(git log -1 --format=%s HEAD~2)
+
-+ amend message from file
++ message
+ EOF
-+ git commit --fixup=amend:HEAD~ -F msgfile &&
-+ get_commit_msg HEAD >actual &&
-+ test_cmp expect actual
+'
+
-+test_expect_success '-F with plain --fixup still errors' '
++test_expect_success 'commit --fixup=reword: works with -F' '
+ commit_for_rebase_autosquash_setup &&
-+ echo "message" >msgfile &&
-+ test_must_fail git commit --fixup HEAD~ -F msgfile 2>err &&
-+ test_grep "cannot be used together" err
-+'
++ echo "message from file" >msgfile &&
++ git commit --fixup=reword:HEAD~ -F msgfile &&
++ test_commit_message HEAD <<-EOF
++ amend! $(git log -1 --format=%s HEAD~2)
+
++ $(cat msgfile)
++ EOF
+ '
+
test_expect_success 'commit --squash works with -F' '
- commit_for_rebase_autosquash_setup &&
- echo "log message from file" >msgfile &&
+@@ t/t7500-commit-template-squash-signoff.sh: test_expect_success 'invalid message options when using --fixup' '
+ git add foo &&
+ test_must_fail git commit --fixup HEAD~1 --squash HEAD~2 &&
+ test_must_fail git commit --fixup HEAD~1 -C HEAD~2 &&
+- test_must_fail git commit --fixup HEAD~1 -c HEAD~2 &&
+- test_must_fail git commit --fixup HEAD~1 -F log
++ test_must_fail git commit --fixup HEAD~1 -c HEAD~2
+ '
+
+ cat >expected-template <<EOF
-: ---------- > 2: b3fc743abf commit: allow -c/-C for all kinds of --fixupbase-commit: 208068f2d8ae29d7edaa245d9975b1b22ec65738
-- 2.54.0.1014.g842965a2d5