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From: Junio C Hamano <gitster@pobox•com>
To: Tanay Abhra <tanayabh@gmail•com>
Cc: git@vger•kernel.org, Ramkumar Ramachandra <artagnon@gmail•com>,
	Matthieu Moy <Matthieu.Moy@grenoble-inp•fr>
Subject: Re: [PATCH v7 5/8] config: add `git_die_config()` to the config-set API
Date: Mon, 04 Aug 2014 11:07:12 -0700	[thread overview]
Message-ID: <xmqqoaw0ruwf.fsf@gitster.dls.corp.google.com> (raw)
In-Reply-To: <1406912756-15517-6-git-send-email-tanayabh@gmail.com> (Tanay Abhra's message of "Fri, 1 Aug 2014 10:05:53 -0700")

Tanay Abhra <tanayabh@gmail•com> writes:

> Add `git_die_config` that dies printing the line number and the file name
> of the highest priority value for the configuration variable `key`.
>
> It has usage in non-callback based config value retrieval where we can
> raise an error and die if there is a semantic error.
> For example,
>
> 	if (!git_config_get_value(key, &value)) {
> 		/* NULL values not allowed */
> 		if (!value)
> 			git_config_die(key);
> 		else
> 			/* do work */
> 	}

It feels a bit unnatural at the API level that this does not take
'value'; I do understand that it is not a big deal in the error code
path to locate again the value from the configuration using the key,
but still.

It feels even more unnatural that the caller cannot say _how_ it
finds the value offending by not taking any message.  For one
particular callchain, e.g. git_config_get_string() that eventually
calls git_config_string() which will show an error message via
config_error_nonbool(), you may not want any extra message, but for
new callers that wants to make sure value falls within a supported
range, this forces it to write

	if (!git_config_get_int(key, &num)) {
        	if (!(0 < num && num < 4)) {
			error("'%s' must be between 1 and 3");
                        git_config_die(key);
		}
		/* otherwise work */
	}

and then the error message would say something like:

	error: 'core.frotz' must be between 1 and 3
	fatal: bad config variable 'core.frotz' at file line 15 in .git/config

which sounds somewhat backwards, at least to me.

> +NORETURN
> +void git_die_config_linenr(const char *key, const char *filename, int linenr)
> +{
> +	if (!linenr)
> +		die(_("unable to parse '%s' from command-line config"), key);

Do we have existing code that says "we signal that it is from the
command line by setting linenr to zero" already?  Otherwise I would
have thought filename == NULL would be a more sensible convention.

Otherwise OK.

> +	else
> +		die(_("bad config variable '%s' at file line %d in %s"),

At least, quote the last '%s'.

> +			key,
> +			linenr,
> +			filename);

Don't waste vertical real-estate line this.

Perhaps

        die(_("bad config variable '%s' in file '%s' at line %d"),
            key, linenr, filename);

  reply	other threads:[~2014-08-04 18:07 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-01 17:05 [PATCH v7 0/8] Rewrite `git_config()` using config-set API Tanay Abhra
2014-08-01 17:05 ` [PATCH v7 1/8] config.c: mark error and warnings strings for translation Tanay Abhra
2014-08-01 17:05 ` [PATCH v7 2/8] config.c: fix accuracy of line number in errors Tanay Abhra
2014-08-04 13:41   ` Matthieu Moy
2014-08-01 17:05 ` [PATCH v7 3/8] add line number and file name info to `config_set` Tanay Abhra
2014-08-01 17:05 ` [PATCH v7 4/8] change `git_config()` return value to void Tanay Abhra
2014-08-01 17:05 ` [PATCH v7 5/8] config: add `git_die_config()` to the config-set API Tanay Abhra
2014-08-04 18:07   ` Junio C Hamano [this message]
2014-08-04 18:55     ` Tanay Abhra
2014-08-04 20:04       ` Matthieu Moy
2014-08-05 14:55         ` Tanay Abhra
2014-08-05 15:15           ` Matthieu Moy
2014-08-05 16:42             ` Junio C Hamano
2014-08-04 20:52       ` Junio C Hamano
2014-08-01 17:05 ` [PATCH v7 6/8] rewrite git_config() to use " Tanay Abhra
2014-08-01 17:05 ` [PATCH v7 7/8] add a test for semantic errors in config files Tanay Abhra
2014-08-04 18:13   ` Junio C Hamano
2014-08-01 17:05 ` [PATCH v7 8/8] add tests for `git_config_get_string_const()` Tanay Abhra
2014-08-04 13:43 ` [PATCH v7 0/8] Rewrite `git_config()` using config-set API Matthieu Moy

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