[LLVMdev] [cfe-dev] RFC: put commit messages in *-commits subject lines?

[Sebastian Pop]

Hi,

Chris Lattner wrote:
> 
> On Nov 15, 2012, at 2:28 PM, Chandler Carruth <chandlerc at google.com> wrote:
> 
> >> [cfe-commits] r167788 - in /cfe/trunk: lib/Analysis/CFG.cpp test/Analysis/dead-stores.cpp
> >> 
> >> with
> >> 
> >> [cfe-commits] r167788 - Fix bad CFG construction bug when handling C++ 'try' statements.
> >> 
> >> The first gives me just enough information (in my abbreviated mesage list window) to see that there was a change to Clang's Analysis library; if I look at the whole subject, I can see what files were changed (or the first few, at least). But the second actually tells me what changed, and whether or not it affects me.
> >> 
> >> Having this form will also encourage people to put a useful summary in the first line of their commit, which is useful for anyone viewing history (especially git users, where the one-line summary is very common).
> >> 
> >> Is there a reason we currently prefer files to log messages?
> > 
> > I suspect not. I would much prefer your suggestion. If you can
> > implement the fix to our scripts (and get Tanya or Chris or Anton to
> > give you access), I would be thrilled.
> 
> I'm in favor of it.  Of course, the truly awesomest thing would be something like:
> 
>     [cfe-commits] r167788 - [lib/Analysis] Fix bad CFG construction bug when handling C++ 'try' statements.
> 
> Even if it required some heuristics and horrible hackery in the commit script, it would be worth it.

I see that currently the commit emails contain this marker in the header:
X-Mailer: svnmailer-1.0.9
So the following fixes assume that we are running svnmailer-1.0.9.

To get the first line of the log message as a subject line, please apply this
one line patch: http://bugs.debian.org/cgi-bin/bugreport.cgi?msg=17;bug=379534
Note that you can directly patch the installed script: on my machine it is
located in /usr/local/lib/python2.7/dist-packages/svnmailer/notifier/_mail.py
and then replace or add the following line to the config file /etc/svn-mailer.conf

commit_subject_template = %(prefix)s r%(revision)s - %(log)s

Also as David Blaikie has pointed out, we are missing an upper bound on the
subject line length, so you may want to consider adding this:

max_subject_length = 120

While we are at it, let's also fix the missing context, by using a custom diff
command with the -p flag.  Here is the config line:

diff_command = /usr/bin/diff -up -L %(label_from)s -L %(label_to)s %(from)s %(to)s 

Can somebody do these modifications to llvm.org's /etc/svn-mailer.conf?

Thanks,
Sebastian
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