Show changes to file permissions in diffs and pull requests

Sometimes a developer will accidentally change the permissions on a file, and check in the change. It would be good to spot these changes before they cause problems, ideally as part of code review when looking at a pull request.

The current web interface doesn't expose this information.

Here's an example commit diff. Which files have changed permissions?

The answer is both of them, but it's hard to spot. The fact that the latter is in the diff with no apparent changes is a hint that the second file has different permissions; I can't see anything to indicate the change in the first file.

Even when I know the permissions have changed, I don't know what the old/new permissions are; this is also useful.

Please add something to the diff view that:

• Highlights when the file permissions have changed
• Tells me the old and new permissions