Subject: Re: [RFC PATCH 7/7] merge: teach --autostash option

From: Denton Liu <[email-masked]>
Date: Tue, 24 Dec 2019 04:58:31 -0500

Hi Phillip,

On Fri, Oct 18, 2019 at 10:46:37AM +0100, Phillip Wood wrote:
> Hi Denton
> 
> On 16/10/2019 18:26, Denton Liu wrote:
> > In rebase, one can pass the `--autostash` option to cause the worktree
> > to be automatically stashed before continuing with the rebase. This
> > option is missing in merge, however.
> 
> It might be helpful to say why this option is useful. I can see one might
> want to stash before doing `git pull` in the same way as one might before a
> rebase but what's the motivation for doing it before a normal merge?

Will do.

> 
> > 
> > Implement the `--autostash` option and corresponding `merge.autoStash`
> > option in merge which stashes before merging and then pops after.
> > 
> > Reported-by: Alban Gruin <[email-masked]>
> > Signed-off-by: Denton Liu <[email-masked]>
> > ---
> >   builtin/merge.c | 13 +++++++++++++
> >   builtin/pull.c  |  9 +++++----
> >   t/t5520-pull.sh |  8 --------
> >   3 files changed, 18 insertions(+), 12 deletions(-)
> > 
> > diff --git a/builtin/merge.c b/builtin/merge.c
> > index 062e911441..d1a5eaad0d 100644
> > --- a/builtin/merge.c
> > +++ b/builtin/merge.c
> > @@ -40,6 +40,7 @@
> >   #include "branch.h"
> >   #include "commit-reach.h"
> >   #include "wt-status.h"
> > +#include "autostash.h"
> >   #define DEFAULT_TWOHEAD (1<<0)
> >   #define DEFAULT_OCTOPUS (1<<1)
> > @@ -58,6 +59,8 @@ static const char * const builtin_merge_usage[] = {
> >   	NULL
> >   };
> > +static GIT_PATH_FUNC(merge_autostash, "MERGE_AUTOSTASH")
> > +
> >   static int show_diffstat = 1, shortlog_len = -1, squash;
> >   static int option_commit = -1;
> >   static int option_edit = -1;
> > @@ -81,6 +84,7 @@ static int show_progress = -1;
> >   static int default_to_upstream = 1;
> >   static int signoff;
> >   static const char *sign_commit;
> > +static int autostash;
> >   static int no_verify;
> >   static struct strategy all_strategy[] = {
> > @@ -285,6 +289,8 @@ static struct option builtin_merge_options[] = {
> >   	OPT_SET_INT(0, "progress", &show_progress, N_("force progress reporting"), 1),
> >   	{ OPTION_STRING, 'S', "gpg-sign", &sign_commit, N_("key-id"),
> >   	  N_("GPG sign commit"), PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
> > +	OPT_BOOL(0, "autostash", &autostash,
> > +	      N_("automatically stash/stash pop before and after")),
> >   	OPT_BOOL(0, "overwrite-ignore", &overwrite_ignore, N_("update ignored files (default)")),
> >   	OPT_BOOL(0, "signoff", &signoff, N_("add Signed-off-by:")),
> >   	OPT_BOOL(0, "no-verify", &no_verify, N_("bypass pre-merge-commit and commit-msg hooks")),
> > @@ -440,6 +446,7 @@ static void finish(struct commit *head_commit,
> >   		strbuf_addf(&reflog_message, "%s: %s",
> >   			getenv("GIT_REFLOG_ACTION"), msg);
> >   	}
> > +	apply_autostash(merge_autostash());
> >   	if (squash) {
> >   		squash_message(head_commit, remoteheads);
> >   	} else {
> > @@ -631,6 +638,9 @@ static int git_merge_config(const char *k, const char *v, void *cb)
> >   	} else if (!strcmp(k, "commit.gpgsign")) {
> >   		sign_commit = git_config_bool(k, v) ? "" : NULL;
> >   		return 0;
> > +	} else if (!strcmp(k, "merge.autostash")) {
> > +		autostash = git_config_bool(k, v);
> > +		return 0;
> >   	}
> >   	status = fmt_merge_msg_config(k, v, cb);
> > @@ -724,6 +734,8 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
> >   		for (j = common; j; j = j->next)
> >   			commit_list_insert(j->item, &reversed);
> > +		if (autostash)
> > +			perform_autostash(merge_autostash());
> >   		hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
> >   		clean = merge_recursive(&o, head,
> >   				remoteheads->item, reversed, &result);
> > @@ -1288,6 +1300,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
> >   		/* Invoke 'git reset --merge' */
> >   		ret = cmd_reset(nargc, nargv, prefix);
> > +		apply_autostash(merge_autostash());
> >   		goto done;
> >   	}
> > diff --git a/builtin/pull.c b/builtin/pull.c
> > index d25ff13a60..ee186781ae 100644
> > --- a/builtin/pull.c
> > +++ b/builtin/pull.c
> > @@ -183,7 +183,7 @@ static struct option pull_options[] = {
> >   		N_("verify that the named commit has a valid GPG signature"),
> >   		PARSE_OPT_NOARG),
> >   	OPT_BOOL(0, "autostash", &opt_autostash,
> > -		N_("automatically stash/stash pop before and after rebase")),
> > +		N_("automatically stash/stash pop before and after")),
> 
> I've not looked closely at the code in this patch but noticed this. I think
> it would read better if it said
> 
>     automatically stash/stash pop before and after pulling

Since this is an `argh` argument, it says that we should "keep it
homogenous across the repository". Since rebase (which I copied it
from), merge and pull will be sharing the same argh string, I think that
we should leave it as is.

Thanks,

Denton

> 
> Best Wishes
> 
> Phillip
> 
> >   	OPT_PASSTHRU_ARGV('s', "strategy", &opt_strategies, N_("strategy"),
> >   		N_("merge strategy to use"),
> >   		0),
> > @@ -671,6 +671,10 @@ static int run_merge(void)
> >   	argv_array_pushv(&args, opt_strategy_opts.argv);
> >   	if (opt_gpg_sign)
> >   		argv_array_push(&args, opt_gpg_sign);
> > +	if (opt_autostash == 0)
> > +		argv_array_push(&args, "--no-autostash");
> > +	else if (opt_autostash == 1)
> > +		argv_array_push(&args, "--autostash");
> >   	if (opt_allow_unrelated_histories > 0)
> >   		argv_array_push(&args, "--allow-unrelated-histories");
> > @@ -918,9 +922,6 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
> >   	if (get_oid("HEAD", &orig_head))
> >   		oidclr(&orig_head);
> > -	if (!opt_rebase && opt_autostash != -1)
> > -		die(_("--[no-]autostash option is only valid with --rebase."));
> > -
> >   	autostash = config_autostash;
> >   	if (opt_rebase) {
> >   		if (opt_autostash != -1)
> > diff --git a/t/t5520-pull.sh b/t/t5520-pull.sh
> > index cf4cc32fd0..75f162495a 100755
> > --- a/t/t5520-pull.sh
> > +++ b/t/t5520-pull.sh
> > @@ -365,14 +365,6 @@ test_expect_success 'pull --rebase --no-autostash & rebase.autostash unset' '
> >   	test_pull_autostash_fail --rebase --no-autostash
> >   '
> > -for i in --autostash --no-autostash
> > -do
> > -	test_expect_success "pull $i (without --rebase) is illegal" '
> > -		test_must_fail git pull $i . copy 2>err &&
> > -		test_i18ngrep "only valid with --rebase" err
> > -	'
> > -done
> > -
> >   test_expect_success 'pull.rebase' '
> >   	git reset --hard before-rebase &&
> >   	test_config pull.rebase true &&
> >