Hi Alex,
On Wed, 22 Feb 2023, Alex Henrie wrote:
> diff --git a/builtin/rebase.c b/builtin/rebase.c
> index b68fc2fbb7..45cf445d42 100644
> --- a/builtin/rebase.c
> +++ b/builtin/rebase.c
> @@ -771,6 +771,20 @@ static int run_specific_rebase(struct rebase_options *opts)
> return status ? -1 : 0;
> }
>
> +static void parse_merges_value(struct rebase_options *options, const char *value)
> +{
> + if (value) {
> + if (!strcmp("no-rebase-cousins", value))
If you want to support `rebase.merges=` to imply `no-rebase-cousins`, this
would be the correct place to do it:
if (!*value || !strcmp("no-rebase-cousins", value))
> + options->rebase_cousins = 0;
> + else if (!strcmp("rebase-cousins", value))
> + options->rebase_cousins = 1;
> + else
> + die(_("Unknown mode: %s"), value);
> + }
> +
> + options->rebase_merges = 1;
I would expect `options->rebase_merges = 0` if `value == NULL`. IOW I
would have expected `parse_merges_value()` to start with:
if (!value) {
options->rebase_merges = 0;
return;
}
This assumes, of course, the parse_options semantics, where a `--no-*` option
passes `NULL` as argument to the callback.
However, this is _not_ the parse_options callback, and if the (optional)
argument was not specified, we do end up with a `NULL` here in spite of
wanting to enable the rebase-merges mode.
However, a primary reason why you introduce the function is to support
config value parsing. And in config value parsing, a "maybe-bool" with a
NULL value is considered to be equivalent to `true`! (See
`git_parse_maybe_bool_text()` or
https://git-scm.com/docs/git-config#Documentation/git-config.txt-true for
details.). For example,
[http]
sslVerify
is equivalent to
[http]
sslVerify = true
But since `git_parse_maybe_bool()` already takes care of handling that
case (in which case we do not even want to call `git_parse_maybe_bool()`),
you can limit that function to handling the command-line semantics.
So with those confusingly disagreeing semantics, I see not only myself,
but other readers doing very, very well, indeed, with a code comment that
explains under what circumstances we expect this callback to be called
with `value == NULL`.
> +}
> +
> static int rebase_config(const char *var, const char *value, void *data)
> {
> struct rebase_options *opts = data;
> @@ -815,6 +829,13 @@ static int rebase_config(const char *var, const char *value, void *data)
> return 0;
> }
>
> + if (!strcmp(var, "rebase.merges") && value && *value) {
Why do we require a non-empty `value` here?
[rebase]
merges
should be equivalent to `true`,
[rebase]
merges =
should probably be equivalent to `false`, and both are handled correctly
by `git_parse_maybe_bool()`.
> + opts->rebase_merges = git_parse_maybe_bool(value);
> + if (opts->rebase_merges < 0)
> + parse_merges_value(opts, value);
> + return 0;
> + }
> +
> if (!strcmp(var, "rebase.backend")) {
> return git_config_string(&opts->default_backend, var, value);
> }
> @@ -980,6 +1001,18 @@ static int parse_opt_empty(const struct option *opt, const char *arg, int unset)
> return 0;
> }
>
> +static int parse_opt_merges(const struct option *opt, const char *arg, int unset)
> +{
> + struct rebase_options *options = opt->value;
> +
> + if (unset)
> + options->rebase_merges = 0;
> + else
> + parse_merges_value(options, arg);
> +
> + return 0;
> +}
> +
It is kind of inelegant to require a _second_ callback for the
command-line parsing, but I guess if we want a `--no-rebase-merges` option
to override a config setting, we cannot help it.
> static void NORETURN error_on_missing_default_upstream(void)
> {
> struct branch *current_branch = branch_get(NULL);
> @@ -1035,7 +1068,6 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
> struct object_id branch_base;
> int ignore_whitespace = 0;
> const char *gpg_sign = NULL;
> - const char *rebase_merges = NULL;
> struct string_list strategy_options = STRING_LIST_INIT_NODUP;
> struct object_id squash_onto;
> char *squash_onto_name = NULL;
> @@ -1137,10 +1169,9 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
> &options.allow_empty_message,
> N_("allow rebasing commits with empty messages"),
> PARSE_OPT_HIDDEN),
> - {OPTION_STRING, 'r', "rebase-merges", &rebase_merges,
> - N_("mode"),
> + OPT_CALLBACK_F('r', "rebase-merges", &options, N_("mode"),
> N_("try to rebase merges instead of skipping them"),
> - PARSE_OPT_OPTARG, NULL, (intptr_t)"no-rebase-cousins"},
> + PARSE_OPT_OPTARG, parse_opt_merges),
> OPT_BOOL(0, "fork-point", &options.fork_point,
> N_("use 'merge-base --fork-point' to refine upstream")),
> OPT_STRING('s', "strategy", &options.strategy,
> @@ -1436,14 +1467,8 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
> if (options.exec.nr)
> imply_merge(&options, "--exec");
>
> - if (rebase_merges) {
> - if (!strcmp("rebase-cousins", rebase_merges))
> - options.rebase_cousins = 1;
> - else if (strcmp("no-rebase-cousins", rebase_merges))
> - die(_("Unknown mode: %s"), rebase_merges);
> - options.rebase_merges = 1;
> + if (options.rebase_merges)
> imply_merge(&options, "--rebase-merges");
> - }
>
> if (options.type == REBASE_APPLY) {
> if (ignore_whitespace)
> diff --git a/t/t3430-rebase-merges.sh b/t/t3430-rebase-merges.sh
> index c73949df18..d4b0e8fd49 100755
> --- a/t/t3430-rebase-merges.sh
> +++ b/t/t3430-rebase-merges.sh
> @@ -284,6 +284,102 @@ test_expect_success '--rebase-merges="" is invalid syntax' '
> test_cmp expect actual
> '
>
> +test_expect_success 'rebase.merges="" is equivalent to not passing --rebase-merges' '
> + test_config rebase.merges "" &&
> + git checkout -b config-merges-blank E &&
> + git rebase C &&
> + test_cmp_graph C.. <<-\EOF
> + * B
> + * D
> + o C
> + EOF
> +'
> +
> +test_expect_success 'rebase.merges=rebase-cousins is equivalent to --rebase-merges=rebase-cousins' '
> + test_config rebase.merges rebase-cousins &&
> + git checkout -b config-rebase-cousins main &&
> + git rebase HEAD^ &&
> + test_cmp_graph HEAD^.. <<-\EOF
> + * Merge the topic branch '\''onebranch'\''
> + |\
> + | * D
> + | * G
> + |/
> + o H
> + EOF
> +'
> +
> +test_expect_success '--no-rebase-merges overrides rebase.merges=no-rebase-cousins' '
> + test_config rebase.merges no-rebase-cousins &&
> + git checkout -b override-config-no-rebase-cousins E &&
> + git rebase --no-rebase-merges C &&
> + test_cmp_graph C.. <<-\EOF
> + * B
> + * D
> + o C
> + EOF
> +'
> +
> +test_expect_success '--rebase-merges=no-rebase-cousins overrides rebase.merges=rebase-cousins' '
> + test_config rebase.merges rebase-cousins &&
> + git checkout -b override-config-rebase-cousins main &&
> + git rebase --rebase-merges=no-rebase-cousins HEAD^ &&
> + test_cmp_graph HEAD^.. <<-\EOF
> + * Merge the topic branch '\''onebranch'\''
> + |\
> + | * D
> + | * G
> + o | H
> + |/
> + o A
> + EOF
> +'
> +
> +test_expect_success '--rebase-merges overrides rebase.merges=false' '
> + test_config rebase.merges false &&
> + git checkout -b override-config-merges-false E &&
> + before="$(git rev-parse --verify HEAD)" &&
> + test_tick &&
> + git rebase --rebase-merges C &&
> + test_cmp_rev HEAD $before
> +'
> +
> +test_expect_success '--rebase-merges does not override rebase.merges=rebase-cousins' '
> + test_config rebase.merges rebase-cousins &&
> + git checkout -b no-override-config-rebase-cousins main &&
> + git rebase --rebase-merges HEAD^ &&
> + test_cmp_graph HEAD^.. <<-\EOF
> + * Merge the topic branch '\''onebranch'\''
> + |\
> + | * D
> + | * G
> + |/
> + o H
> + EOF
> +'
> +
> +test_expect_success 'local rebase.merges=false overrides global rebase.merges=true' '
> + test_config_global rebase.merges true &&
> + test_config rebase.merges false &&
> + git checkout -b override-global-config E &&
> + git rebase C &&
> + test_cmp_graph C.. <<-\EOF
> + * B
> + * D
> + o C
> + EOF
> +'
> +
> +test_expect_success 'local rebase.merges="" does not override global rebase.merges=true' '
> + test_config_global rebase.merges no-rebase-cousins &&
> + test_config rebase.merges "" &&
> + git checkout -b no-override-global-config E &&
> + before="$(git rev-parse --verify HEAD)" &&
> + test_tick &&
> + git rebase C &&
> + test_cmp_rev HEAD $before
> +'
> +
I understand the temptation to introduce exhaustive matrices that test all
the different settings in all the different ways they can be specified.
However, I would much prefer to keep the tests succinct, not the least to
avoid the every-increasing runtime of Git's CI. It's already taking about
an order of magnitude or two too long to be reasonable.
So I'd suggest reducing the tests to a single one instead of eight: verify
that `rebase.merges=no-rebase-cousins` is heeded, and that
`--no-rebase-cousins` overrides that. That should be plenty sufficient to
prevent regressions.
Ciao,
Johannes
> test_expect_success 'refs/rewritten/* is worktree-local' '
> git worktree add wt &&
> cat >wt/script-from-scratch <<-\EOF &&
> --
> 2.39.2
>
>
