Re: [PATCHv3 1/4] clone: respect additional configured fetch refspecs during initial fetch

From: Jeff King <peff@peff.net>
Date: May 26, 2017, 13:30 UTC
Message-ID: <20170526133024.g5rztiv3lea37n72@sigill.intra.peff.net>
In-Reply-To: <20170526100403.19270-1-szeder.dev@gmail.com>

On Fri, May 26, 2017 at 12:04:03PM +0200, SZEDER Gábor wrote:

Show 11 quoted lines

> > but given that it lazy-parses in
> > some cases, it feels a little dangerous.
> 
> I'm not sure about lazy parsing.
> remote_get() returns a fully-parsed, cached struct remote instance
> without re-reading the configuration, so all fields directly
> corresponding to configuration variables stay the same.  However, it
> does parse fetch and push refspecs on every invocation.  So if it were
> to be called to return the origin remote more than once during
> cloning, then the default refspec would get lost on subsequent
> invocations.  Is this what you meant with dangerous?

More or less. I actually didn't look far enough to see under what circumstances we might re-parse (or might not have parsed when we add our extra refspec), but that's definitely the sort of thing I was worried about.

> (Sidenote: and it would leak some memory, too, because it re-parses
> the refspecs without free()ing the results of the previous
> invocation.)

Yes, I'd argue that the current code is buggy, since:

  x = remote_get("foo");
  y = remote_get("foo");

is a guaranteed leak. It seems like remote_get_1() should protect the call to parse_fetch_refspec() by checking whether ret->fetch is NULL (and ditto for ret->push).

> Your proposed function to add a refspec as a string would eliminate
> this danger.

Yeah, I think it's not that hard to support. I'd just rather have the logic inside remote.c, rather than infecting the caller with the complexity.

Show 11 quoted lines

> It certainly looks better, see the patch below the scissors for
> reference, and I thought it works because until last night I only run
> the corresponding test script (t5611-clone-config), though I know very
> well that "Thou shalt always run the full test suite!" :)
> 
> Unfortunately, putting the default refspec into this temporary
> configuration environment breaks a few submodule tests
> (t5614-clone-submodules or t5614-clone-submodules-shallow (it's got
> renamed between this topic and master), t7407-submodule-foreach,
> t7410-submodule-checkout-to), because it "leaks" to the submodule
> environment.

Doh, of course. I didn't think of that. That's probably a bad direction, then, as there's no "just for this process" global config.

-Peff