From: Phillip Wood Date: Wed, 12 Nov 2025 14:48:21 GMT Subject: Re: [PATCH v6 4/4] rebase: support --trailer Message-ID: <0413bf2e-52c4-4944-a349-2a922dd463a2@gmail.com> In-Reply-To: <20251105142944.73061-5-me@linux.beauty> Hi Li On 05/11/2025 14:29, Li Chen wrote: > From: Li Chen > > diff --git a/Documentation/git-rebase.adoc b/Documentation/git-rebase.adoc > index 005caf6164..4d2fe4be6e 100644 > --- a/Documentation/git-rebase.adoc > +++ b/Documentation/git-rebase.adoc > @@ -487,9 +487,16 @@ See also INCOMPATIBLE OPTIONS below. > Add a `Signed-off-by` trailer to all the rebased commits. Note > that if `--interactive` is given then only commits marked to be > picked, edited or reworded will have the trailer added. > -+ > + > See also INCOMPATIBLE OPTIONS below. > > +--trailer=:: > + Append the given trailer line(s) to every rebased commit I'm not sure we need to say "line(s)" here. "Append the given trailer to every ..." would be fine I think. > + message, processed via linkgit:git-interpret-trailers[1]. > + When this option is present *rebase automatically implies* > + `--force-rebase` so that fast‑forwarded commits are also > + rewritten. Normally in cases like this we just say "This option implies `--force-rebase`". > diff --git a/builtin/rebase.c b/builtin/rebase.c > index c468828189..a88abe08b4 100644 > --- a/builtin/rebase.c > +++ b/builtin/rebase.c > @@ -500,6 +508,23 @@ static int read_basic_state(struct rebase_options *opts) > opts->gpg_sign_opt = xstrdup(buf.buf); > } > > + strbuf_reset(&buf); > + > + if (strbuf_read_file(&buf, state_dir_path("trailer", opts), 0) >= 0) { > + const char *p = buf.buf, *end = buf.buf + buf.len; > + > + while (p < end) { > + char *nl = memchr(p, '\n', end - p); > + if (!nl) > + die("nl shouldn't be NULL"); > + *nl = '\0'; > + > + if (*p) > + strvec_push(&opts->trailer_args, p); > + > + p = nl + 1; > + } > + } As "--trailer" is only supported by the "merge" backend we only need to read this file in sequencer.c:read_populate_opts(), there is no point in reading it here. > strbuf_release(&buf); > > return 0; > @@ -528,6 +553,21 @@ static int rebase_write_basic_state(struct rebase_options *opts) > if (opts->signoff) > write_file(state_dir_path("signoff", opts), "--signoff"); > > + /* > + * save opts->trailer_args into state_dir/trailer > + */ As "--trailer" is not supported by the "apply" backend we can just rely on this being written by sequener.c:write_basic_state(), we don't need to do it here > + if (opts->trailer_args.nr) { > + struct strbuf buf = STRBUF_INIT; > + > + for (size_t i = 0; i < opts->trailer_args.nr; i++) { > + strbuf_addstr(&buf, opts->trailer_args.v[i]); > + strbuf_addch(&buf, '\n'); > + } > + write_file(state_dir_path("trailer", opts), > + "%s", buf.buf); > + strbuf_release(&buf); > + } > + > return 0; > } > > @@ -1132,6 +1172,8 @@ int cmd_rebase(int argc, > .flags = PARSE_OPT_NOARG, > .defval = REBASE_DIFFSTAT, > }, > + OPT_STRVEC(0, "trailer", &options.trailer_args, N_("trailer"), > + N_("add custom trailer(s)")), This line should be indented so that the "N_" aligns with "0" above like all the other options here. Putting this next to "--signoff" is a good choice. > diff --git a/sequencer.c b/sequencer.c > index 5476d39ba9..fbf35cb474 100644 > --- a/sequencer.c > +++ b/sequencer.c > @@ -2025,6 +2027,10 @@ static int append_squash_message(struct strbuf *buf, const char *body, > if (opts->signoff) > append_signoff(buf, 0, 0); > > + if (opts->trailer_args.nr && > + amend_strbuf_with_trailers(buf, &opts->trailer_args)) > + return error(_("unable to add trailers to commit message")); amend_strbuf_with_trailers() cannot really fail so this should be if (opts->trailer_args.nr) amend_strbuf_with_trailers(buf, &opts->trailer_args)); > @@ -2443,6 +2449,14 @@ static int do_pick_commit(struct repository *r, > if (opts->signoff && !is_fixup(command)) > append_signoff(&ctx->message, 0, 0); > > + if (opts->trailer_args.nr && !is_fixup(command)) { > + if (amend_strbuf_with_trailers(&ctx->message, > + &opts->trailer_args)) { > + res = error(_("unable to add trailers to commit message")); > + goto leave; > + } As above amend_strbuf_with_trailers() cannot fail so we don't need this error handling > + } > + > if (is_rebase_i(opts) && write_author_script(msg.message) < 0) > res = -1; > else if (!opts->strategy || > @@ -2517,6 +2531,7 @@ static int do_pick_commit(struct repository *r, > _("dropping %s %s -- patch contents already upstream\n"), > oid_to_hex(&commit->object.oid), msg.subject); > } /* else allow == 0 and there's nothing special to do */ > + We try to avoid introducing unrelated white space changes > @@ -3234,6 +3249,17 @@ static int read_populate_opts(struct replay_opts *opts) > > read_strategy_opts(opts, &buf); > strbuf_reset(&buf); > + if (strbuf_read_file(&buf, rebase_path_trailer(), 0) >= 0) { > + char *p = buf.buf, *nl; > + > + while ((nl = strchr(p, '\n'))) { > + *nl = '\0'; > + if (*p) As we're in control of what's written to the file it is a BUG() if to contains any empty line. > diff --git a/sequencer.h b/sequencer.h > index 719684c8a9..e21835c5a0 100644 > --- a/sequencer.h > +++ b/sequencer.h > @@ -44,6 +44,7 @@ struct replay_opts { > int record_origin; > int no_commit; > int signoff; > + struct strvec trailer_args; I think it would be better to add this after all the flag options > int allow_ff; > int allow_rerere_auto; > int allow_empty; > @@ -82,8 +83,9 @@ struct replay_opts { > struct replay_ctx *ctx; > }; > #define REPLAY_OPTS_INIT { \ > - .edit = -1, \ ".edit" is the first member so it makes sense to leave this at the start. > .action = -1, \ > + .edit = -1, \ > + .trailer_args = STRVEC_INIT, \ > .xopts = STRVEC_INIT, \ > .ctx = replay_ctx_new(), \ > } > diff --git a/t/t3440-rebase-trailer.sh b/t/t3440-rebase-trailer.sh > new file mode 100755 > index 0000000000..d0e0434664 > --- /dev/null > +++ b/t/t3440-rebase-trailer.sh > @@ -0,0 +1,134 @@ > +#!/bin/sh > +# > + > +test_description='git rebase --trailer integration tests > +We verify that --trailer works with the merge backend, > +and that it is rejected early when the apply backend is requested.' > + > +GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main > +export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME > + > +. ./test-lib.sh > +. "$TEST_DIRECTORY"/lib-rebase.sh # test_commit_message, helpers > + > +REVIEWED_BY_TRAILER="Reviewed-by: Dev " > + > +expect_trailer_msg() { > + test_commit_message "$1" <<-EOF > + $2 > + > + ${3:-$REVIEWED_BY_TRAILER} > + EOF > +} > + > +test_expect_success 'setup repo with a small history' ' > + git commit --allow-empty -m "Initial empty commit" && > + test_commit first file a && > + test_commit second file && > + git checkout -b conflict-branch first && > + test_commit file-2 file-2 && > + test_commit conflict file && > + test_commit third file This leaves us with conflict-branch checked out, is that intentional? > +' > + > +test_expect_success 'apply backend is rejected with --trailer' ' > + head_before=$(git rev-parse HEAD) && I'm not sure we really need to check that HEAD is unchanged here > + test_expect_code 128 \ > + git rebase --apply --trailer "$REVIEWED_BY_TRAILER" \ > + HEAD^ 2>err && > + test_grep "fatal: --trailer requires the merge backend" err && > + test_cmp_rev HEAD $head_before > +' > + > +test_expect_success 'reject empty --trailer argument' ' > + test_expect_code 128 git rebase -m --trailer "" HEAD^ 2>err && There is no need to pass "-m" in any of these tests as it is the default and if the default backend changes in the future we will want "--trailer" keeps working with the new default. > + test_grep "empty --trailer" err > +' > + > +test_expect_success 'reject trailer with missing key before separator' ' > + test_expect_code 128 git rebase -m --trailer ": no-key" HEAD^ 2>err && > + test_grep "missing key before separator" err > +' > + > +test_expect_success 'allow trailer with missing value after separator' ' > + git rebase -m --trailer "Acked-by:" HEAD~1 third && > + sed -e "s/_/ /g" <<-\EOF >expect && > + third > + > + Acked-by:_ > + EOF > + test_commit_message HEAD expect test_commit_message accepts a message on stdin so we don't need to create expect in all these tests. It is curious that we add a trailing space to the trailer, it would be nice if we could clean that up. Failing that other tests use SP=" " and then use ${SP} in the here document like test_commit_message HEAD <<-EOF third Acked-by:${SP} EOF > +' > + > +test_expect_success 'CLI trailer duplicates allowed; replace policy keeps last' ' > + git -c trailer.Bug.ifexists=replace -c trailer.Bug.ifmissing=add \ > + rebase -m --trailer "Bug: 123" --trailer "Bug: 456" HEAD~1 third && > + cat >expect <<-\EOF && > + third > + > + Bug: 456 > + EOF > + test_commit_message HEAD expect > +' > + > +test_expect_success 'multiple Signed-off-by trailers all preserved' ' > + git rebase -m \ > + --trailer "Signed-off-by: Dev A " \ > + --trailer "Signed-off-by: Dev B " HEAD~1 third && The massive indentation here leads to overly long lines. git rebase --trailer "Signed-off-by: Dev A " \ --trailer "Signed-off-by: Dev B " HEAD~1 third && fits our 80 column limit > + cat >expect <<-\EOF && > + third > + > + Signed-off-by: Dev A > + Signed-off-by: Dev B > + EOF > + test_commit_message HEAD expect > +' > + > +test_expect_success 'rebase -m --trailer adds trailer after conflicts' ' > + git checkout -B conflict-branch third && I'm not sure why we're recreating conflict-branch here, you can just run "git rebase [options] second third" > + test_commit fourth file && > + test_must_fail git rebase -m \ > + --trailer "$REVIEWED_BY_TRAILER" \ > + second && If you unfold this line it is 79 characters long which is perfctly fine. > + git checkout --theirs file && > + git add file && > + git rebase --continue && > + expect_trailer_msg HEAD "fourth" && I think it would be easier to see what's being checked if we just used test_commit_message as we have done up to here and got rid of the test_trailer_msg. > + expect_trailer_msg HEAD^ "third" This is good because we check that the conflicting commit gets a trailer and the commit picked by "git rebase --continue" does too. > +' > + > +test_expect_success '--trailer handles fixup commands in todo list' ' > + git checkout -B fixup-trailer HEAD && If you're going to create a new branch you should do it from a tag so it has a known starting point that is not dependent on the previous tests. > + test_commit fixup-base base && > + test_commit fixup-second second && > + first_short=$(git rev-parse --short fixup-base) && > + second_short=$(git rev-parse --short fixup-second) && These two lines are unecessary as test_commit() creates a tag which we can use in the todo list. The here document should also be indented. So > + cat >todo < +pick $first_short fixup-base > +fixup $second_short fixup-second > +EOF becomes cat >todo <<-\EOF && pick fixup-base first-base fixup fixup-second fixup-second EOF > + ( > + set_replace_editor todo && > + git rebase -i --trailer "$REVIEWED_BY_TRAILER" HEAD~2 > + ) && > + expect_trailer_msg HEAD "fixup-base" && We check there is only one trailer after the fixup - good > + git reset --hard fixup-second && > + cat >todo < +pick $first_short fixup-base > +fixup -C $second_short fixup-second > +EOF > + ( > + set_replace_editor todo && > + git rebase -i --trailer "$REVIEWED_BY_TRAILER" HEAD~2 > + ) && > + expect_trailer_msg HEAD "fixup-second" We check that we add a trailer with "fixup -C" - good> +' > + > +test_expect_success 'rebase --root --trailer updates every commit' ' > + git checkout first && > + git -c trailer.review.key=Reviewed-by rebase --root \ > + --trailer=review="Dev " && It would be good if the test title mentioned that we're also checking 'trailer..key' here as well which is more interesting than "--root" > + expect_trailer_msg HEAD "first" && > + expect_trailer_msg HEAD^ "Initial empty commit" The test coverage looks good > +' > +test_done > diff --git a/trailer.c b/trailer.c > index f5838f5699..f6ff2f01ee 100644 > --- a/trailer.c > +++ b/trailer.c > @@ -774,6 +775,30 @@ void parse_trailers_from_command_line_args(struct list_head *arg_head, > free(cl_separators); > } > > +void validate_trailer_args_after_config(const struct strvec *cli_args) I think "validate_trailer_args" would be a sufficient name > +{ > + char *cl_separators; > + > + trailer_config_init(); > + > + cl_separators = xstrfmt("=%s", separators); > + > + for (size_t i = 0; i < cli_args->nr; i++) { > + const char *txt = cli_args->v[i]; > + ssize_t separator_pos; > + > + if (!*txt) > + die(_("empty --trailer argument")); > + > + separator_pos = find_separator(txt, cl_separators); > + if (separator_pos == 0) > + die(_("invalid trailer '%s': missing key before separator"), > + txt); Strange indentation here, but the implementation looks sensible. Overall this is looking good. I've left lots of comments but they're all small issues Thanks Phillip > + } > + > + free(cl_separators); > +} > + > static const char *next_line(const char *str) > { > const char *nl = strchrnul(str, '\n'); > @@ -1226,8 +1251,8 @@ void trailer_iterator_release(struct trailer_iterator *iter) > strbuf_release(&iter->key); > } > > -static int amend_strbuf_with_trailers(struct strbuf *buf, > - const struct strvec *trailer_args) > +int amend_strbuf_with_trailers(struct strbuf *buf, > + const struct strvec *trailer_args) > { > struct process_trailer_options opts = PROCESS_TRAILER_OPTIONS_INIT; > LIST_HEAD(new_trailer_head); > diff --git a/trailer.h b/trailer.h > index daea46ca5d..541657a11f 100644 > --- a/trailer.h > +++ b/trailer.h > @@ -68,6 +68,8 @@ void parse_trailers_from_config(struct list_head *config_head); > void parse_trailers_from_command_line_args(struct list_head *arg_head, > struct list_head *new_trailer_head); > > +void validate_trailer_args_after_config(const struct strvec *cli_args); > + > void process_trailers_lists(struct list_head *head, > struct list_head *arg_head); > > @@ -195,6 +197,9 @@ int trailer_iterator_advance(struct trailer_iterator *iter); > */ > void trailer_iterator_release(struct trailer_iterator *iter); > > +int amend_strbuf_with_trailers(struct strbuf *buf, > + const struct strvec *trailer_args); > + > /* > * Augment a file to add trailers to it (similar to 'git interpret-trailers'). > * Returns 0 on success or a non-zero error code on failure.