ChangeLog love

[Geert Janssens]

I'm looking into the remaining bits preventing a full git migration when 2.6 will be released.

One item on the list is our automatic changelog generation in the toplevel's makefile. This 
currently converts the svn log into a GNU style ChangeLog file.

It's easy to replicate something very similar based on the git logs in one single command:
git log --format="%ai %aN %n%n%x09* %s%d%n"

There's two minor differences:
- The date is formatted slightly differently (git includes time info, svn doesn't)
- The author's name is full name, derived from authors e-mail (git) instead of unix login name 
(svn)

I have no objections to these changes. If you do, please shout.

But looking into this raise a number of questions on the ChangeLog in general. I'll just ask 
them here:

1. Starting with the most basic one: why are we generating changelogs at all ? Both svn and 
git have commands to easily extract all this information in one go. So I don't understand why 
we want to keep this history checked in.

2. For release tarballs, I can understand a bit better. The tarballs don't have all the revision 
history available. But should each release really contain *all* the history ? Isn't it sufficient 
and even more relevant to record only the changes that went into the release being shipped ? 
Our current ChangLog format makes it a little confusing to figure out which change actually 
got into which release version. Additionally our first release in each new development series 
(like 2.5.0) usually takes more than a year before it gets released, compared to the branching 
point. So for those releases the current ChangLog is always incomplete.

3. Given the limited added value of the ChangeLog compared to git/svn logs, does it still 
make sense to store the ChangeLog files in the repo ? They can be generated on the fly as 
well when needed. A quick test on my git repo gives me the full changelog from the very first 
commit in 1997 to present in less than 5 seconds...

4. So considering all the above, wouldn't it make more sense to simply generate ChangeLogs 
on the fly only for tarball generation ?


These questions are not criticisms, but really intended to stimulate us to review or current 
ChangeLog process. Is it still ok or time to improve ?

Geert