Re: [PATCH v2] clean: improve -n and -f implementation and documentation

[Sergey Organov <sorganov@gmail.com>]

Junio C Hamano <gitster@pobox.com> writes:

> Sergey Organov <sorganov@gmail.com> writes:
>
>> Changes since v1:
>>
>>  * Fixed style of the if() statement
>>
>>  * Merged two error messages into one
>>
>>  * clean.requireForce description changed accordingly
>
> Excellent.
>
>> diff --git a/builtin/clean.c b/builtin/clean.c
>> index d90766cad3a0..41502dcb0dde 100644
>> --- a/builtin/clean.c
>> +++ b/builtin/clean.c
>> @@ -25,7 +25,7 @@
>>  #include "help.h"
>>  #include "prompt.h"
>>
>> -static int force = -1; /* unset */
>> +static int require_force = -1; /* unset */
>>  static int interactive;
>>  static struct string_list del_list = STRING_LIST_INIT_DUP;
>>  static unsigned int colopts;
>> @@ -128,7 +128,7 @@ static int git_clean_config(const char *var, const char *value,
>>  	}
>>
>>  	if (!strcmp(var, "clean.requireforce")) {
>> -		force = !git_config_bool(var, value);
>> +		require_force = git_config_bool(var, value);
>>  		return 0;
>>  	}
>>
>> @@ -920,7 +920,7 @@ int cmd_clean(int argc, const char **argv, const char *prefix)
>>  {
>>  	int i, res;
>>  	int dry_run = 0, remove_directories = 0, quiet = 0, ignored = 0;
>> -	int ignored_only = 0, config_set = 0, errors = 0, gone = 1;
>> +	int ignored_only = 0, force = 0, errors = 0, gone = 1;
>>  	int rm_flags = REMOVE_DIR_KEEP_NESTED_GIT;
>>  	struct strbuf abs_path = STRBUF_INIT;
>>  	struct dir_struct dir = DIR_INIT;
>> @@ -946,22 +946,17 @@ int cmd_clean(int argc, const char **argv, const char *prefix)
>>  	};
>>
>>  	git_config(git_clean_config, NULL);
>> -	if (force < 0)
>> -		force = 0;
>> -	else
>> -		config_set = 1;
>
> The above changes are a significant improvement.  Instead of a
> single "force" variable whose meaning is fuzzy, we now have
> "require_force" to track the config setting, and "force" to indicate
> the "--force" option.  THis makes the code's intent much clearer.
>
>>  	argc = parse_options(argc, argv, prefix, options, builtin_clean_usage,
>>  			     0);
>>
>> -	if (!interactive && !dry_run && !force) {
>> -		if (config_set)
>> -			die(_("clean.requireForce set to true and neither -i, -n, nor -f given; "
>> -				  "refusing to clean"));
>> -		else
>> -			die(_("clean.requireForce defaults to true and neither -i, -n, nor -f given;"
>
> And thanks to that, the above trick with an extra variable "config_set",
> which smells highly a round-about way, can be simplified.
>
>> +	/* Dry run won't remove anything, so requiring force makes no sense */
>> +	if (dry_run)
>> +		require_force = 0;
>> +	if (require_force != 0 && !force && !interactive)
>
> However, the above logic could be improved.  The behaviour we have,
> for a user who does *not* explicitly disable config.requireForce,
> is, that when clean.requireForce is not set to 0, we would fail
> unless one of these is in effect: -f, -n, -i.  Even though using
> either -n or -i makes it unnecessary to use -f *exactly* the same
> way, the above treats dry_run and interactive separately with two if
> statements, which is suboptimal as a "code/logic clean-up".

I wonder do you mean:

	/* Dry run won't remove anything, so requiring force makes no
	* sense. Interactive has its own means of protection, so don't
	* require force as well */
	if (dry_run || interactive)
		require_force = 0;

	if (require_force != 0 && !force)
                die_();

that looks fine to me, as it puts 'force' flag and corresponding
configuration into one if(), whereas both exceptions are put into
another. OTOH, having:

     if (require_force != 0 && !force && !interactive && !dry_run)
                die_();

mixture looks less appealing to me, though I won't fight against it
either.

>
> The reason for the behaviour can be explained this way:
>
>  * "git clean" (with neither -i nor -n.  The user wants the default
>    mode that has no built-in protection will be stopped without -f.
>
>  * "git clean -n".  The user wants the dry-run mode that has its own
>    protection, i.e. being always no-op to the files, so there is no
>    need to fail here for the lack of "-f".
>
>  * "git clean --interactive".  The user wants the interactive mode
>    that has its own protection, i.e. giving the end-user a chance to
>    say "oh, I didn't mean to remove these files, 'q'uit from this
>    mistake", so there is no need to fail here for the lack of "-f".

Well, if we remove -i from error message as well, then yes, this makes
sense.

>
>> +		die(_("clean.requireForce is true and neither -f nor -i given:"
>>  				  " refusing to clean"));
>
> The message is certainly cleaner compared to the previous round, but
> this also can be improved.  Stepping back a bit and thinking who are
> the target audience of this message.  The only users who see this
> message are running "git clean" in its default (unprotected) mode,
> and they wanted to "clean" for real.  If they wanted to do dry-run,
> they would have said "-n" themselves, and that is why we can safely
> omit mention of "-n" we had in the original message.
>
> These users did not want to run the interractive clean, either---if
> they wanted to go interractive, they would have said "-i"
> themselves.  So we do not need to mention "-i" either for exactly
> the same logic.

I then suggest to consider to remove mention of -i from
clean.requireForce description as well.

>
> Based on the above observation,
>
> I'll send a follow-up patch to clean up the code around here (both
> implementation and documentation), taking '-i' into account as well.

Fine, thanks!

-- Sergey Organov