How do I check for potential merge/rebase conflicts in Mercurial?

Question

Is there a simple way to check if a merge/rebase will yield file conflicts, without actually performing the merge/rebase?

I want to be able to decide whether to:

Answer 1

So, with some aid from Martin's answer, I've come up with the rebaseif extension, which does what I want.

Essentially, it tries to rebase using the internal merge tool, if that fails (which it does for any conflict), it aborts and does a merge with the user's preferred tool.

See https://bitbucket.org/marcusl/ml-hgext/src/tip/rebaseif.py for details.

Update

In recent months, I've gone back to just do a merge, since it's inherently safe. A non-conflict rebase might still muck things up since dependent files can affect the change. (i.e. a rebase loses information of how the code looked before merge).

As the rebaseif author, I recommend to use plain old merge instead. :)