Re: [PATCH v4] gc: call "prune --expire 2.weeks.ago" by default

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 12, 2008, 21:20 UTC
Message-ID: <7vwso74p33.fsf@gitster.siamese.dyndns.org>
In-Reply-To: <alpine.LSU.1.00.0803122153440.1656@racer.site>

Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:

> ---prune::

I am fairly paranoid about end users wondering about what is described in ancient documentation and complaining that we do not talk about it anymore. I am tempted to suggest:

	This is a no-op but you may see it mentioned in older docs and
	scripts.  Older git-gc never ran 'prune' without being told, and
	this option was a way to tell it to.

but this would lead to littering the documentation with too much historical information in the long run. I dunno. I am inclined to favor the removal as your patch did, but somebody else may have clever ideas.

Show 6 quoted lines

> +	if (!strcmp(var, "gc.pruneexpire")) {
> +		if (!value)
> +			return config_error_nonbool(var);
> +		if (strcmp(value, "now") &&
> +				approxidate(value) - approxidate("now") >= 0)
> +			return error("Invalid gc.pruneExpire: '%s'", value);

Yuck; approxidate() returns ulong. Can subtracting a ulong from another ever go negative?

Besides, because there is no guarantee of the order of evaluation between these two approxidate() calls, you may get +1 or -1 on the second boundary.

I think the reason why you did not catch it in your test is because your tests are half complete; they test only what you wanted to catch (misconfigured case) and do not test the other half (properly working case).