Hi Glen,
Le 2022-05-09 à 19:27, Glen Choo via GitGitGadget a écrit :
> From: Glen Choo <chooglen@xxxxxxxxxx>
First, regarding the commit message title (I never know where to comment
on that since I can't quote it :P)
> Re: [PATCH] pull: only pass '--recurse-submodules' to subcommands
I understand the intent, i.e. "only pass the CLI flag, not any config, to subcommands"
but only because I already know what the patch is about. It could be
read to mean "pass --recurse-submodules only to subcommands, and not to
something else". Since this is really a bug that affects the underlying
'git fetch', maybe something like this ?
pull: pass '--recurse-submodules' to 'fetch' from CLI, not config
>
> Fix a bug in "git pull" where `submodule.recurse` is preferred over
> `fetch.recurseSubmodules`
here I would add "for the underlying 'git fetch'"
(Documentation/config/fetch.txt says that
> `fetch.recurseSubmodules` should be preferred.). Do this by passing the
> value of the "--recurse-submodules" CLI option to the underlying fetch,
> instead of passing a value that combines the CLI option and config
> variables.
>
> In other words, this bug occurred because builtin/pull.c is conflating
> two similar-sounding, but different concepts:
>
> - Whether "git pull" itself should care about submodules e.g. whether it
> should update the submodule worktrees after performing a merge.
nit: "or rebase".
> - The value of "--recurse-submodules" to pass to the underlying "git
> fetch".
>
> Thus, when `submodule.recurse` is set, the underlying "git fetch" gets
> invoked with "--recurse-submodules", overriding the value of
> `fetch.recurseSubmodules`.
the wording is a litlle bit misleading here, as submodule.recurse could
be set to 'false', and then 'git fetch' will be invoked with '--recurse-submodules=false'.
> An alternative (and more obvious) approach to fix the bug would be to
> teach "git pull" to understand `fetch.recurseSubmodules`, but the
> proposed solution works better because:
>
> - We don't maintain two identical config-parsing implementions in "git
> pull" and "git fetch".
> - It works better with other commands invoked by "git pull" e.g. "git
> merge" won't accidentally respect `fetch.recurseSubmodules`.
I'm not sure of the meaning of the second bullet, since "git merge" should
never perform a fetch ?...
>
> Reported-by: Huang Zou <huang.zou@xxxxxxxxxxxxxxx>
> Helped-by: Philippe Blain <levraiphilippeblain@xxxxxxxxx>
> Signed-off-by: Glen Choo <chooglen@xxxxxxxxxx>
> ---
> pull: only pass '--recurse-submodules' to subcommands
>
> Thanks Huang Zou for the report [1], and Philippe Blain for the initial
> investigation.
>
> This patch fixes the original bug, but not in the 'obvious' way of
> teaching "git pull" to parse fetch.recurseSubmodules. Instead, "git
> pull" now propagates its value of "--recurse-submodules" to "git fetch"
> (ignoring any config values), and leaves the config parsing to "git
> fetch".
>
> I think this works better because we get a nice separation of "config
> that git pull cares about" and "config that its subprocess care about",
> and as a result:
>
> * We don't maintain two identical config-parsing implementations in
> "git pull" and "git fetch".
> * It works better with other commands invoked by "git pull" e.g. "git
> merge" won't accidentally respect fetch.recurseSubmodules.
>
> PS I'm having a hard time writing today, let me know how the commit
> message/cover letter can be improved :)
>
> [1]
> https://lore.kernel.org/git/CAFnZ=JNE_Sa3TsKghBPj1d0cz3kc6o91Ogj-op8o6qK8t9hPgg@xxxxxxxxxxxxxx
>
> In-Reply-To:
> CAFnZ=JNE_Sa3TsKghBPj1d0cz3kc6o91Ogj-op8o6qK8t9hPgg@xxxxxxxxxxxxxx
>
> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1262%2Fchooglen%2Fpull%2Ffetch-recurse-submodules-v1
> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1262/chooglen/pull/fetch-recurse-submodules-v1
> Pull-Request: https://github.com/git/git/pull/1262
>
> builtin/pull.c | 10 +++++++---
> t/t5572-pull-submodule.sh | 14 ++++++++++++++
> 2 files changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/builtin/pull.c b/builtin/pull.c
> index 4d667abc19d..01155ba67b2 100644
> --- a/builtin/pull.c
> +++ b/builtin/pull.c
> @@ -72,6 +72,7 @@ static const char * const pull_usage[] = {
> static int opt_verbosity;
> static char *opt_progress;
> static int recurse_submodules = RECURSE_SUBMODULES_DEFAULT;
> +static int recurse_submodules_cli = RECURSE_SUBMODULES_DEFAULT;
>
> /* Options passed to git-merge or git-rebase */
> static enum rebase_type opt_rebase = -1;
> @@ -120,7 +121,7 @@ static struct option pull_options[] = {
> N_("force progress reporting"),
> PARSE_OPT_NOARG),
> OPT_CALLBACK_F(0, "recurse-submodules",
> - &recurse_submodules, N_("on-demand"),
> + &recurse_submodules_cli, N_("on-demand"),
> N_("control for recursive fetching of submodules"),
> PARSE_OPT_OPTARG, option_fetch_parse_recurse_submodules),
>
> @@ -536,8 +537,8 @@ static int run_fetch(const char *repo, const char **refspecs)
> strvec_push(&args, opt_tags);
> if (opt_prune)
> strvec_push(&args, opt_prune);
> - if (recurse_submodules != RECURSE_SUBMODULES_DEFAULT)
> - switch (recurse_submodules) {
> + if (recurse_submodules_cli != RECURSE_SUBMODULES_DEFAULT)
> + switch (recurse_submodules_cli) {
> case RECURSE_SUBMODULES_ON:
> strvec_push(&args, "--recurse-submodules=on");
> break;
> @@ -1001,6 +1002,9 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
>
> argc = parse_options(argc, argv, prefix, pull_options, pull_usage, 0);
>
> + if (recurse_submodules_cli != RECURSE_SUBMODULES_DEFAULT)
> + recurse_submodules = recurse_submodules_cli;
> +
I agree with you and Junio that this implementation is very clear
and concise. Nice!
> if (cleanup_arg)
> /*
> * this only checks the validity of cleanup_arg; we don't need
> diff --git a/t/t5572-pull-submodule.sh b/t/t5572-pull-submodule.sh
> index fa6b4cca65c..65aaa7927fb 100755
> --- a/t/t5572-pull-submodule.sh
> +++ b/t/t5572-pull-submodule.sh
> @@ -107,6 +107,20 @@ test_expect_success " --[no-]recurse-submodule and submodule.recurse" '
> test_path_is_file super/sub/merge_strategy_4.t
> '
>
> +test_expect_success "fetch.recurseSubmodules option triggers recursive fetch (but not recursive update)" '
> + test_commit -C child merge_strategy_5 &&
> + git -C parent submodule update --remote &&
> + git -C parent add sub &&
> + git -C parent commit -m "update submodule" &&
> +
> + git -C super -c fetch.recursesubmodules=true pull --no-rebase &&
> + # Check that the submodule commit was fetched
> + sub_oid=$(git -C super rev-parse FETCH_HEAD:sub) &&
> + git -C super/sub cat-file -e $sub_oid &&
> + # Check that the submodule worktree did not update
> + ! test_path_is_file super/sub/merge_strategy_5.t
> +'
> +
OK so here we test the following situation:
fetch.recurseSubmodules submodule.recurse --recurse-submodules fetch result pull result
----------------------- ----------------- -------------------- ------------ ------------
true unset absent recursive not recursive
I think this is a good start, but since the default behaviour
of Git is the following:
fetch.recurseSubmodules submodule.recurse --recurse-submodules fetch result pull result
----------------------- ----------------- -------------------- ------------ ------------
default: on-demand default: false unset on-demand not recursive
we end up testing something not very far from the default behaviour. I think
this answers Junio's question as to why the test does not fail when applied
without the fix. So I think for completeness, we should add more tests,
including (maybe) the configuration that Huang reported:
fetch.recurseSubmodules submodule.recurse --recurse-submodules fetch result pull result
----------------------- ----------------- -------------------- ------------- ------------
false true absent not recursive* recursive
* the submodule will be fetched by 'git submodule update', not by the 'git fetch' ran by 'git pull'
and probably also this configuration that I think is what Huang wanted to achieve:
fetch.recurseSubmodules submodule.recurse --recurse-submodules fetch result pull result
----------------------- ----------------- -------------------- ------------- ------------
on-demand false absent on-demand recursive
and probably this one also:
fetch.recurseSubmodules submodule.recurse --recurse-submodules fetch result pull result
----------------------- ----------------- -------------------- ------------- ------------
on-demand true absent on-demand recursive
and maybe some others with an explicit '--recurse-submodules' flag on the CLI.
I must tell you that I think there is another bug I think in the 'git fetch' config parsing
for 'fetch.recurseSubmodules' and 'submodule.recurse'. Even if 'fetch.recurseSubmodules'
is documented as overriding 'submodule.recurse', this is actually not enforced
in 'git_fetch_config', currently it's a "last one wins" situation so the actualy behaviour
depends on which config is encountered last in the config file(s)...
Thanks for taking this on,
Philippe.
