Re: [Monotone-devel] Re: cannot drop non-empty directory during branch update

[Zack Weinberg]

On 9/18/07, William Uther <address@hidden> wrote:
> I'm not sure this makes a real difference.  Either you want to re-
> generate them or you don't.  If you don't want to re-generate them
> then you should add them.

I have nothing in particular to add to the rest of the discussion, but
I want to point out that there are legitimate use cases for putting
generated files into version control.  The one I know about is when
the source changes rarely *and* you need an unusual tool to do the
regeneration.  For example, there's this thing called AutoGen (has
absolutely nothing in common with automake or autoconf, except that I
believe the name was inspired by them) which is used to generate
several files inside the GCC repository, such as the 'fixincludes'
script.  The script doesn't change often and we don't want to make
people have the tool.

It occurs to me that Monotone could do nice things for this scenario
with a specialized cert on the derivative file, identifying the
source(s) by file ID and content hash.  This would have two effects:
if the source file is being checked in and the derivative file isn't,
the commit is rejected; and on checkout we somehow ensure that the
last modification time of the derivative file is later than the last
modification time of the source files.  (GCC has a horrible
post-checkout script you're supposed to run to do this.  It would be
*really nice* if it happened automatically.)

zw