[LispM-Hackers] Commit Policy
James A. Crippen
Tue Apr 9 19:17:01 2002
JM brought up the question of commit policy with me. This is always
an interesting issue, and the answer is usually vague. I've worked on
both open-source and commercial projects using CVS, and have found a
number of rules that help to maintain a happy environment for
Here's some basic commit policy rules:
* DON'T commit things that won't compile.
It's *extremely* frustrating to do a 'cvs update' and then suddenly
find that some random part of the program won't compile, preventing
you from working on your stuff until you can dike out the breakage
or revert the files to older, compilable versions.
* DON'T commit binaries (eg, object files, bands, coredumps, etc).
Why? Because the CVS repo isn't set up to handle them
automatically. If you do really want to add a binary somewhere then
please discuss it on the list beforehand. We will decide whether it
really needs to be in the repo, and if so where, and how to
correctly handle binary files with CVS (which requires special
* DON'T commit output.
Output belongs on the list, on the webpage, or on personal pages.
Not in the repository. Same with debugging dumps.
* DON'T commit platform specific things without non-specific handling.
Thus, if you're writing code to support FooOS don't commit changes
to code without properly conditionalizing the support so that it
doesn't show up on every platform. Just because you think 64-bit
support would be n34t on the Alpha doesn't mean that people using
Vaxen will like it integrated in their build, even if GCC can
magically make it work.
These are things to think about before you commit something. Does it
compile? Is it platform specific with appropriate conditionalization?
Is it text-only? Etc...
As for when you *should* commit, please commit when you can fulfill
above restrictions. Here's some rules regarding how commits should be
* Commit regularly.
Even if the changes you've made are small, try to commit them. They
may not seem important to you but someone else may be encountering a
bug that is fixed by your changes. If you commit often you will
also avoid development out of sync with the project. Your repo copy
will tend to stay in sync better if you keep your commits up to
* Commit in semantically related chunks.
Don't commit the changes you've made in the last week all with one
commit. Try to break it up into related chunks and commit each
separately. Thus changes to memory management code should be
committed separately from the graphics code unless they're obviously
* Use descriptive commit logs, but keep them short.
Don't use the commit logs as a forum for describing your woes and
ideas. The commit logs are just a record for why commits are made,
and what is included in each commit. If you find yourself writing
more than 25 lines of log text then you should take the details to
the list as a followup post to your commit log mail message. But
don't just use one-liner logs like "Fixes bug #422369." That's
useful if you happen to be looking at the bug database (which we
don't have yet, but will). But most people do not read commit logs
while looking at the bug database. If the bug is simple enough or
has a 'name' then describe or name it, *and* include the bug
* Try not to spam commits.
If you've got five thousand and one things you want to commit,
please don't commit them all at once if you can. Commit one chunk
at a time, then leave the repo alone for a while before you commit
the next thing. Some people work in a very distracted fashion,
first hacking one thing, then another. They build up a big pile of
unrelated changes and then want to commit them all at once. Instead
they should commit one thing at a time, then wait for the other
developers to evaluate the changes before committing the next set of
changes. This keeps other developers from being confused by changes
that occur all over the source tree in seemingly random ways, that
might introduce new bugs.
Any other suggestions? When we all agree on policy I'll put up a web
page for it.
James A. Crippen <email@example.com> ,-./-. Anchorage, Alaska,
Lambda Unlimited: Recursion 'R' Us | |/ | USA, 61.20939N, -149.767W
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