We also need git-receive-pack (git ssh), git-upload-pack (git ssh), svnserve (any svn hosting?) and svnadmin (any svn hosting). For Mercurial, apparently hg is sufficient in all cases. (We could possibly rewrite the git-*-pack commands we receive over SSH to git *-pack, but I'm slightly hesitant about that.)

With this approach, I'm worried that it will be somewhat overwhelming and not actually as useful as it could be:

• We'll potentially warn you about a lot of binaries you don't actually need, since we don't check if these repositories are hosted.
• Whether we check if the repositories are hosted or not, this message probably comes too late. It generally will show up only after the next restart, so users without these binaries will probably hit "configure repo" -> "it doesn't work" -> "no clue how to proceed" without seeing this.

Instead, what do you think about moving this check to DiffusionRepositoryEditMainController::buildRepositoryStatus()? It could check for exactly the binaries that the repository needs based on whether it is hosted or not, and present the information to the user at a relevant time.

That's probably a better option.

I've always liked the idea of caching / storing exceptions that happen "behind-the-scenes" and then displaying a yellow bar to Administrators that exceptions have occurred. We could even use this to display exceptions in daemons out to Administrators so that they are aware that exceptions are occurring.