Re: multiple working directories for long-running builds (was: "git merge" merges too much!)

From: Greg A. Woods <woods@planix.com>
Date: Dec 1, 2009, 18:58 UTC
Message-ID: <m1NFXvL-000kn2C@most.weird.com>
In-Reply-To: <20091201185114.GC11235@dpotapov.dyndns.org>

At Tue, 1 Dec 2009 21:51:14 +0300, Dmitry Potapov <dpotapov@gmail.com> wrote:
Subject: Re: multiple working directories for long-running builds (was:	"git merge" merges too much!)

Show 5 quoted lines

> 
> Obviously, switching branches while running build may produce very
> confusing results, but it is not any different than editing files by
> hands during built -- any concurrent modification may confuse the build
> system.

That's what I said. This is why multiple working directories is an essential feature for any significantly large project.

Show 7 quoted lines

> > I just disagreed that "git archive" was a reasonable alternative to
> > leaving the working directory alone during the entire time of the build.
> 
> Using "git archive" allows you avoid running long time procedure such as
> full clean build and testing in the working tree. Also, it is guaranteed
> that you test exactly what you put in Git and some other garbage in your
> working tree does not affect the result.

Sure, but let's be very clear here: "git archive" is likely even more impossible for some large projects to use than "git clone" would be to use to create build directories.

Disk bandwidth is almost always more expensive than disk space.

>   But my point was that switching
> between branches and recompile a few changed files may be faster than
> going to another working tree.

That's possibly going to generate even more unnecessary churn in the working directory, and thus even more unnecessary re-compiles.

Multiple working directories are really the only sane solution sometimes.

-- 
						Greg A. Woods
						Planix, Inc.

<woods@planix.com>       +1 416 218 0099        http://www.planix.com/