Subject: Re: [PATCH v2 2/2] builtin/reflog.c: switch to use parse-options API for delete subcommand

From: Junio C Hamano <[email-masked]>
Date: Mon, 03 Jan 2022 18:36:42 -0800

"John Cai via GitGitGadget" <[email-masked]> writes:

> From: John Cai <[email-masked]>
>
> Address NEEDSWORK by switching out manual arg parsing for the
> parse-options API for the delete subcommand.
>
> Moves explicit_expiry flag into cmd_reflog_expire_cb struct so a
> callback can set both the value of the expiration as well as the
> explicit_expiry flag.
>
> Signed-off-by: "John Cai" <[email-masked]>
> ---
>  builtin/reflog.c | 168 ++++++++++++++++++++++++-----------------------
>  1 file changed, 87 insertions(+), 81 deletions(-)
>
> diff --git a/builtin/reflog.c b/builtin/reflog.c
> index 175c83e7cc2..3552d749e4b 100644
> --- a/builtin/reflog.c
> +++ b/builtin/reflog.c
> @@ -12,15 +12,6 @@
>  #include "reachable.h"
>  #include "worktree.h"
>  
> -/* NEEDSWORK: switch to using parse_options */
> -static const char reflog_expire_usage[] =
> -N_("git reflog expire [--expire=<time>] "
> -   "[--expire-unreachable=<time>] "
> -   "[--rewrite] [--updateref] [--stale-fix] [--dry-run | -n] "
> -   "[--verbose] [--all] <refs>...");
> -static const char reflog_delete_usage[] =
> -N_("git reflog delete [--rewrite] [--updateref] "
> -   "[--dry-run | -n] [--verbose] <refs>...");
>  static const char reflog_exists_usage[] =
>  N_("git reflog exists <ref>");
>  
> @@ -30,6 +21,7 @@ static timestamp_t default_reflog_expire_unreachable;
>  struct cmd_reflog_expire_cb {
>  	struct rev_info revs;
>  	int stalefix;
> +	int explicit_expiry;
>  	timestamp_t expire_total;
>  	timestamp_t expire_unreachable;
>  	int recno;
> @@ -504,18 +496,17 @@ static int reflog_expire_config(const char *var, const char *value, void *cb)
>  	return 0;
>  }
>  
> -static void set_reflog_expiry_param(struct cmd_reflog_expire_cb *cb, int slot, const char *ref)
> +static void set_reflog_expiry_param(struct cmd_reflog_expire_cb *cb, const char *ref)
>  {
>  	struct reflog_expire_cfg *ent;
> -
> -	if (slot == (EXPIRE_TOTAL|EXPIRE_UNREACH))
> +	if (cb->explicit_expiry == (EXPIRE_TOTAL|EXPIRE_UNREACH))
>  		return; /* both given explicitly -- nothing to tweak */
>  
>  	for (ent = reflog_expire_cfg; ent; ent = ent->next) {
>  		if (!wildmatch(ent->pattern, ref, 0)) {
> -			if (!(slot & EXPIRE_TOTAL))
> +			if (!(cb->explicit_expiry & EXPIRE_TOTAL))
>  				cb->expire_total = ent->expire_total;
> -			if (!(slot & EXPIRE_UNREACH))
> +			if (!(cb->explicit_expiry & EXPIRE_UNREACH))
>  				cb->expire_unreachable = ent->expire_unreachable;
>  			return;
>  		}
> @@ -525,27 +516,75 @@ static void set_reflog_expiry_param(struct cmd_reflog_expire_cb *cb, int slot, c
>  	 * If unconfigured, make stash never expire
>  	 */
>  	if (!strcmp(ref, "refs/stash")) {
> -		if (!(slot & EXPIRE_TOTAL))
> +		if (!(cb->explicit_expiry & EXPIRE_TOTAL))
>  			cb->expire_total = 0;
> -		if (!(slot & EXPIRE_UNREACH))
> +		if (!(cb->explicit_expiry & EXPIRE_UNREACH))
>  			cb->expire_unreachable = 0;
>  		return;
>  	}
>  
>  	/* Nothing matched -- use the default value */
> -	if (!(slot & EXPIRE_TOTAL))
> +	if (!(cb->explicit_expiry & EXPIRE_TOTAL))
>  		cb->expire_total = default_reflog_expire;
> -	if (!(slot & EXPIRE_UNREACH))
> +	if (!(cb->explicit_expiry & EXPIRE_UNREACH))
>  		cb->expire_unreachable = default_reflog_expire_unreachable;
>  }

OK.

> +static const char * reflog_expire_usage[] = {
> +	N_("git reflog expire [--expire=<time>] "
> +   "[--expire-unreachable=<time>] "
> +   "[--rewrite] [--updateref] [--stale-fix] [--dry-run | -n] "
> +   "[--verbose] [--all] <refs>..."),
> +	NULL
> +};
> +
> +static int expire_unreachable_callback(const struct option *opt,
> +				 const char *arg,
> +				 int unset)
> +{
> +	struct cmd_reflog_expire_cb *cmd = opt->value;
> +	cmd->explicit_expiry |= EXPIRE_UNREACH;
> +	return parse_opt_expiry_date(&cmd->expire_unreachable, arg, unset);

Just as I suspected in the previous step.  Get rid of [1/2] and
add the new helper as a static function to this file.

The thing is that we shouldn't confuse future developers by adding a
random function that cannot be used as OPTION_CALLBACK function in
the parse-options-cb.c file.

> +	for (int i = 0; i < argc; i++) {

Documentation/CodingGuidelines:

 - Declaring a variable in the for loop "for (int i = 0; i < 10; i++)"
   is still not allowed in this codebase.

We have floated a weather balloon by adding a single use of this
construct so that when somebody finds a compiler that do not like
the construct it is easy to revert, and waiting for a feedback.  We
do not want to add the use of the construct to random places yet
that makes us scramble and revert them from all over the place.

>  		const char *spec = strstr(argv[i], "@{");
>  		char *ep, *ref;
>  		int recno;