Re: [PATCH v2] config: improve error message for boolean config

> On Tue, Feb 09, 2021 at 01:25:08AM +0000, Andrew Klotz via GitGitGadget wrote:
>
>> Currently invalid boolean config values return messages about 'bad
>> numeric', which is slightly misleading when the error was due to a
>> boolean value. We can improve the developer experience by returning a
>> boolean error message when we know the value is neither a bool text or
>> int.
>
> Thanks for keeping at this. The goal makes sense. The implementation
> looks OK to me, but I had a few really tiny comments.
>
>> before with an invalid boolean value of `non-boolean`, its unclear what
>> numeric is referring to:
>> ```
>> fatal: bad numeric config value 'non-boolean' for 'commit.gpgsign': invalid unit
>> ```
>> 
>> now the error message mentions `non-boolean` is a bad boolean value:
>> ```
>> fatal: bad boolean config value 'non-boolean' for 'commit.gpgsign'
>> ```
>
> Our commit messages aren't generally formatted as markdown. So this
> looks a little nicer using indentation (which also happens to generate
> nice markdown output):
>
>   numeric is referring to:
>
>       fatal: bad numeric config value 'non-boolean' for 'commit.gpgsign': invalid unit
>
>   now the error message mentions `non-boolean` is a bad boolean value:
>
>       fatal: bad boolean config value 'non-boolean' for 'commit.gpgsign'
>
> Not worth a re-roll on its own, though.
>
>> +NORETURN
>> +static void die_bad_bool(const char *name, const char *value)
>> +{
>> +	if (!strcmp(name, "GIT_TEST_GETTEXT_POISON"))
>> +		/*
>> +		 * We explicitly *don't* use _() here since it would
>> +		 * cause an infinite loop with _() needing to call
>> +		 * use_gettext_poison().
>> +		 */
>> +		die("bad boolean config value '%s' for '%s'", value, name);
>> +	else
>> +		die(_("bad boolean config value '%s' for '%s'"), value, name);
>> +}
>
> The duplication is ugly, but I think it's the least-bad solution (and I
> still dream that GETTEXT_POISON may one day go away :) ).
>
>> @@ -1102,8 +1116,11 @@ int git_config_bool_or_int(const char *name, const char *value, int *is_bool)
>>  
>>  int git_config_bool(const char *name, const char *value)
>>  {
>> -	int discard;
>> -	return !!git_config_bool_or_int(name, value, &discard);
>> +	int v = git_parse_maybe_bool(value);
>> +	if (0 <= v)
>> +		return v;
>> +	else
>> +		die_bad_bool(name, value);
>
> I had to look at this a minute to be sure we always returned a value.
> But the compiler knows that die_bad_bool() doesn't return, and that we
> always take one of the two conditionals.
>
> I do think it might be easier to read as:
>
>   int v = git_parse_maybe_bool(value);
>   if (v < 0)
>           die_bad_bool(name, value);
>   return v;
>
> but I admit that's nit-picking.

>> diff --git a/t/t0205-gettext-poison.sh b/t/t0205-gettext-poison.sh
>> index f9fa16ad8363..b66d34c6f2bc 100755
>> --- a/t/t0205-gettext-poison.sh
>> +++ b/t/t0205-gettext-poison.sh
>> @@ -33,7 +33,7 @@ test_expect_success 'eval_gettext: our eval_gettext() fallback has poison semant
>>  
>>  test_expect_success "gettext: invalid GIT_TEST_GETTEXT_POISON value doesn't infinitely loop" "
>>  	test_must_fail env GIT_TEST_GETTEXT_POISON=xyz git version 2>error &&
>> -	grep \"fatal: bad numeric config value 'xyz' for 'GIT_TEST_GETTEXT_POISON': invalid unit\" error
>> +	grep \"fatal: bad boolean config value 'xyz' for 'GIT_TEST_GETTEXT_POISON'\" error
>>  "
>
> Do we want a separate test in t1300 that doesn't rely on GETTEXT_POISON
> continuing to hang around (the idea has been thrown around elsewhere of
> it maybe going away entirely)?