Re: master 38fb5f4: Make make-dist more automatic

[Paul Eggert <eggert@cs.ucla.edu>]

Glenn Morris wrote:
> I like the simplification, but I have some issues with the MANIFEST file.

Yes, it's a bit of a wart.

> 1) I don't think it should be linked to --no-update. The MANIFEST file
> is fundamental to creating a tar file and it needs to be up-to-date.
> As it stands, if you use --no-update you can easily end up with a stale
> MANIFEST file and a broken tar file. If it does need to be optional,
> please can it have a separate eg --no-update-manifest option.

It would be easy to change make-dist to rebuild MANIFEST regardless of 
--no-update, and I don't see any problem with that.

> 2) Running make-dist leaves a top-level MANIFEST file that nothing ever
> deletes. Since in the vast majority of the time this file will be an
> automatically generated file, I think it would be better to use a
> temporary file. This also takes care of point 1.
> 
> Here's a possible patch.
> This excludes itself MANIFEST from the tar file.
> It could be re-added, but I don't know what the point would be.

The point of shipping MANIFEST is to handle the following situation:

1. User gets an Emacs tarball and extracts it.

2. User changes the source code.

2. User runs "make dist".

Without the MANIFEST file, step (3) would fail because no Git repository is 
available to tell make-dist the names of most of the source files.

If it's OK for us to say, "You must have a Git repository in order to make a 
distribution" then we can dispense with shipping a MANIFEST file; we might even 
be able to dispense from generate a manifest file at all, even a temporary one. 
But if we want to decouple having Git from the ability to make a distribution, 
we'll need something like a MANIFEST file (unless we want to go back to the old 
approach of listing files in make-dist itself, which was error-prone).