Re: [PATCH 1/2] builtin/reflog.c: use parse-options for expire subcommand

[John Cai <johncai86@gmail.com>]

> On Jan 1, 2022, at 3:16 AM, René Scharfe <l.s.r@web.de> wrote:
> 
> Am 01.01.22 um 03:06 schrieb John Cai:
>> 
>> 
>>> On Dec 30, 2021, at 10:29 PM, John Cai via GitGitGadget <gitgitgadget@gmail.com> wrote:
>>> 
>>> From: John Cai <johncai86@gmail.com>
>>> 
>>> Switch out manual argv parsing for the reflog expire subcommand to use
>>> the parse-options API.
>>> 
>>> Signed-off-by: "John Cai" <johncai86@gmail.com>
>>> ---
>>> builtin/reflog.c | 72 ++++++++++++++++++++++++------------------------
>>> 1 file changed, 36 insertions(+), 36 deletions(-)
>>> 
>>> diff --git a/builtin/reflog.c b/builtin/reflog.c
>>> index 175c83e7cc2..afaf5ba67e2 100644
>>> --- a/builtin/reflog.c
>>> +++ b/builtin/reflog.c
>>> @@ -11,13 +11,8 @@
>>> #include "revision.h"
>>> #include "reachable.h"
>>> #include "worktree.h"
>>> +#include "parse-options.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>...");
>>> @@ -539,6 +534,14 @@ static void set_reflog_expiry_param(struct cmd_reflog_expire_cb *cb, int slot, c
>>> 		cb->expire_unreachable = default_reflog_expire_unreachable;
>>> }
>>> 
>>> +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 cmd_reflog_expire(int argc, const char **argv, const char *prefix)
>>> {
>>> 	struct expire_reflog_policy_cb cb;
>>> @@ -547,6 +550,29 @@ static int cmd_reflog_expire(int argc, const char **argv, const char *prefix)
>>> 	int explicit_expiry = 0;
>>> 	unsigned int flags = 0;
>>> 
>>> +	const struct option options[] = {
>>> +		OPT_BIT(0, "dry-run", &flags, N_("do not actually prune any entries"),
>>> +				EXPIRE_REFLOGS_DRY_RUN),
>>> +		OPT_BIT(0, "rewrite", &flags,
>>> +				N_("rewrite the old SHA1 with the new SHA1 of the entry that now precedes it"),
>>> +				EXPIRE_REFLOGS_REWRITE),
>>> +		OPT_BIT(0, "updateref", &flags,
>>> +				N_("update the reference to the value of the top reflog entry"),
>>> +				EXPIRE_REFLOGS_UPDATE_REF),
>>> +		OPT_BIT(0, "verbose", &flags, N_("print extra information on screen."),
>>> +				EXPIRE_REFLOGS_VERBOSE),
>>> +		OPT_EXPIRY_DATE(0, "expire", &cb.cmd.expire_total,
>>> +				N_("prune entries older than the specified time")),
>>> +		OPT_EXPIRY_DATE(0, "expire-unreachable", &cb.cmd.expire_unreachable,
>>> +			N_("prune entries older than <time> that are not reachable from the current tip of the branch")),
>>> +		OPT_BOOL(0, "stale-fix", &cb.cmd.stalefix,
>>> +				N_("prune any reflog entries that point to broken commits")),
>>> +		OPT_BOOL(0, "all", &do_all, N_("process the reflogs of all references")),
>>> +		OPT_BOOL(1, "single-worktree", &all_worktrees,
>>> +				N_("limits processing to reflogs from the current worktree only.")),
>>> +		OPT_END()
>>> +	};
>>> +
>>> 	default_reflog_expire_unreachable = now - 30 * 24 * 3600;
>>> 	default_reflog_expire = now - 90 * 24 * 3600;
>>> 	git_config(reflog_expire_config, NULL);
>>> @@ -560,41 +586,15 @@ static int cmd_reflog_expire(int argc, const char **argv, const char *prefix)
>>> 
>>> 	for (i = 1; i < argc; i++) {
>> 
>> I was hoping we could get rid of this for loop altogether, but I
>> couldn’t figure out a clean way since --expire and
>> expire-unreachable take a value __and__ set a flag bit. So I kept
>> this for loop for the sole purpose of setting the explicit_expiry bit
>> flag. Any suggestions?
> 
> The problem is that the default value can vary between reflogs and we
> only know which ones are to be expired after option parsing, right?

That’s a good point. Does it matter that the default value varies between reflogs?

Would something like this suffice?

-       for (i = 1; i < argc; i++) {
-               const char *arg = argv[i];
-               if (starts_with(arg, "--expire=")) {
-                       explicit_expiry |= EXPIRE_TOTAL;
-               } else if (starts_with(arg, "--expire-unreachable=")) {
-                       explicit_expiry |= EXPIRE_UNREACH;
-               }
-       }
-
        argc = parse_options(argc, argv, prefix, options, reflog_expire_usage, 0);

+       if (cb.cmd.expire_total != default_reflog_expire)
+               explicit_expiry |= EXPIRE_TOTAL;
+       if (cb.cmd.expire_unreachable != default_reflog_expire_unreachable)
+               explicit_expiry |= EXPIRE_UNREACH;


> 
> The easiest way is probably to initialize the date variables to a
> magic value that is unlikely to be specified explicitly.
> parse_expiry_date() already uses two such magic values: 0 for "never"
> and TIME_MAX for "now".  Perhaps 1 for "default"?
> 
> 	cb.cmd.expire_total = cb.cmd.expire_unreachable = 1;
> 
> 	argc = parse_options(...);
> 
> 	if (cb.cmd.expire_total == 1)
> 		cb.cmd.expire_total = default_reflog_expire;
> 	else
> 		explicit_expiry |= EXPIRE_TOTAL;
> 	if (cb.cmd.expire_unreachable == 1)
> 		cb.cmd.expire_unreachable = default_reflog_expire_unreachable;
> 	else
> 		explicit_expiry |= EXPIRE_UNREACH;
> 
> A somewhat cleaner approach would be to store that bit separately:
> 
> 	struct expire_date {
> 		unsigned is_explicitly_set:1;
> 		timestamp_t at;
> 	};
> 
> ... and add a callback function that wraps parse_opt_expiry_date_cb(),
> expects the new struct (instead of timestamp_t directlly) and sets
> that bit.
> 
>> 
>>> 		const char *arg = argv[i];
>>> -
>>> -		if (!strcmp(arg, "--dry-run") || !strcmp(arg, "-n"))
>>> -			flags |= EXPIRE_REFLOGS_DRY_RUN;
>>> -		else if (skip_prefix(arg, "--expire=", &arg)) {
>>> -			if (parse_expiry_date(arg, &cb.cmd.expire_total))
>>> -				die(_("'%s' is not a valid timestamp"), arg);
>>> +		if (starts_with(arg, "--expire=")) {
>>> 			explicit_expiry |= EXPIRE_TOTAL;
>>> -		}
>>> -		else if (skip_prefix(arg, "--expire-unreachable=", &arg)) {
>>> -			if (parse_expiry_date(arg, &cb.cmd.expire_unreachable))
>>> -				die(_("'%s' is not a valid timestamp"), arg);
>>> +		} else if (starts_with(arg, "--expire-unreachable=")) {
>>> 			explicit_expiry |= EXPIRE_UNREACH;
>>> 		}
>>> -		else if (!strcmp(arg, "--stale-fix"))
>>> -			cb.cmd.stalefix = 1;
>>> -		else if (!strcmp(arg, "--rewrite"))
>>> -			flags |= EXPIRE_REFLOGS_REWRITE;
>>> -		else if (!strcmp(arg, "--updateref"))
>>> -			flags |= EXPIRE_REFLOGS_UPDATE_REF;
>>> -		else if (!strcmp(arg, "--all"))
>>> -			do_all = 1;
>>> -		else if (!strcmp(arg, "--single-worktree"))
>>> -			all_worktrees = 0;
>>> -		else if (!strcmp(arg, "--verbose"))
>>> -			flags |= EXPIRE_REFLOGS_VERBOSE;
>>> -		else if (!strcmp(arg, "--")) {
>>> -			i++;
>>> -			break;
>>> -		}
>>> -		else if (arg[0] == '-')
>>> -			usage(_(reflog_expire_usage));
>>> -		else
>>> -			break;
>>> 	}
>>> 
>>> +	argc = parse_options(argc, argv, prefix, options, reflog_expire_usage, 0);
>>> +
>>> 	/*
>>> 	 * We can trust the commits and objects reachable from refs
>>> 	 * even in older repository.  We cannot trust what's reachable
>>> --
>>> gitgitgadget