Re: [PATCH 2/2] archive: avoid spawning `gzip`

From: Jeff King <peff@peff.net>
Date: Apr 15, 2019, 21:36 UTC
Message-ID: <20190415213659.GC28128@sigill.intra.peff.net>
In-Reply-To: <20190413221646.GL12419@genre.crustytoothpaste.net>

On Sat, Apr 13, 2019 at 10:16:46PM +0000, brian m. carlson wrote:

Show 11 quoted lines

> > The alternative is that we could use a special token like ":zlib" or
> > something to indicate that the internal implementation should be used
> > (and then tweak the baked-in default, too). That might be less
> > surprising for users, but most people would still get the benefit since
> > they'd be using the default config.
> 
> I agree that a special value (or NULL, if that's possible) would be
> nicer here. That way, if someone does specify a custom gzip, we honor
> it, and it serves to document the code better. For example, if someone
> symlinked pigz to gzip and used "gzip -cn", then they might not get the
> parallelization benefits they expected.

Thanks for spelling that out. I had a vague feeling somebody might be surprised, but I didn't know if people actually did stuff like symlinking pigz to gzip (though it makes perfect sense to do so).

> I'm fine overall with the idea of bringing the compression into the
> binary using zlib, provided that we preserve the "-n" behavior
> (producing reproducible archives).

I just assumed that gzwrite() would have the "-n" behavior, but it's definitely worth double-checking.

-Peff