extensions: use ismoduleinternal() thoroughly "ships-with-hg-core" would be long enough to typo.

lock: show more detail for new-style locks in lock waiting message (issue4752) Improve the lock waiting warning message by explicitly saying that a host and process are holding the lock. This nudges confused new users in the direction of investigating the other process instead of removing the lock.

formatter: add context manager interface for convenience And port "hg files" to test it. As you can see, extra indent is necessary to port to this API. I don't think we should switch every fm.formatter() call to "with" statement.

histedit: remove now unused 'constraints' related code Now that the one action that need different logic handle that using inheritance and overriding, we can remove that code.

histedt: use inheritance to override the constraints in 'base' All actions but one actually have the same constraints when it comes to validate the 'action.node' value. So we actually just add this code to a method that can be overwritten in the one action where it matters. The now unused 'contraints' related enum and class attribute will be cleaned up in the next changeset.

histedit: move constraint verification to the 'action.verify' method Action has a method dedicated to verifying its validity. So we move code related to constrains into that method. This requires a bit more context to the 'verify' method in the same fashion we were passing the 'prev' argument. This is an extra step before we can simplify the constraint handling code further.