view CONTRIBUTING @ 51929:93d872a06132

typing: add type annotations to the dirstate classes

The basic procedure here was to use `merge-pyi` to merge the `git/dirstate.pyi`
file in (after renaming the interface class to match), cleaning up the import
statement mess, and then repeating the procedure for `mercurial/dirstate.pyi`.
Surprisingly, git's dirstate had more hints inferred in its *.pyi file.

After that, it was a manual examination of each method in the interface, and how
they were implemented in the core and git classes to verify what was inferred by
pytype, and fill in the missing gaps.  Since this involved jumping around
between three different files, I applied the same type info to all three at the
same time.  Complex types I rolled up into type aliases in the interface module,
and used that as needed.  That way if it changes, there's one place to edit.

There are some hints still missing, and some documentation that doesn't match
the signatures.  They should all be marked with TODOs.  There are also a bunch
of methods on the core class that aren't on the Protocol class that seem like
maybe they should be (like `set_tracked()`).  There are even more methods
missing from the git class.  But that's a project for another time.

Our full contribution guidelines are in our wiki, please see:

https://www.mercurial-scm.org/wiki/ContributingChanges

If you just want a checklist to follow, you can go straight to

https://www.mercurial-scm.org/wiki/ContributingChanges#Submission_checklist

If you can't run the entire testsuite for some reason (it can be
difficult on Windows), please at least run `contrib/check-code.py` on
any files you've modified and run `python contrib/check-commit` on any
commits you've made (for example, `python contrib/check-commit
273ce12ad8f1` will report some style violations on a very old commit).