As we approach a release at Palantir we usually cut to a stable branch that QA can start testing as a release candidate. Further bug fixing and testing may continue on trunk by the developers, but we code review changes before committing them to the stable branch. As the time to really cut the release gets truly imminent we start asking questions like:

What changes are on trunk that are not in the stable branch?

We’re less concerned with what the changes are and more concerned with who owns the changes. What really want to know is:

Do the changes on trunk represent pending changes that should be moved to stable or are they further development that shouldn’t be put into the stable branch for this release?

For the most part, the person that can answer that question is the coder who made the changes on trunk. To that end, what we really would love to have would be a report of all files in trunk that differ from the stable branch and who last touched the file. There isn’t really an svn command that will do this succintly, so I started thinking about how to accomplish this. I had an inkling that it could be all solved with a single Unix pipeline and so I set out on my way to craft such a beast. Here’s what I came up with in about ten minutes:

for name in `diff -r --brief --exclude=.svn pgstable/src pgtrunk/src  | awk '{print $4}' | grep pgtrunk `; do
    author=`svn info $name | grep -E "Last Changed Author" | awk '{print $4}'`;
    echo $author    $name;
done | sort | sed 's/pgtrunk\\/src\\///' > difflist.txt

Which produces output that looks like this:

gbush com/palantir/foo/Bar.java
bclinton com/palantir/baz/Fargle.java

How did I come up with such a beast? I deconstruct this inscrutable wonder after the jump.
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