configitems: enable pullbundles by default The use of pullbundles is already protected: they are only used when a pullbundles.manifest file is created on the server. Having an additional flag doesn't really make sense and can confuse users (as indicated in the mercurial mailing list on the topic "Can't get pull-bundles working").

upgrade: byteify requirement changes written to output ui.write() expects bytes, and internally uses `b''` as the default when getting the `label` keyword from `*args`. So either we're missing test coverage, or there's some very subtle conversion from unicode somewhere. Also, slip in a type hint to flag this in the future.

typing: add basic type hints to stringutil.py

vfs: make the default opener mode binary The default was already binary for `abstractvfs`, and the `vfs` implementation adds binary mode if the caller didn't supply it. Therefore, it should be safe for all vfs objects (and I don't think we want text reads anyway).

typing: add basic type hints to vfs.py Again, there's a lot more that could be done, but this sticks to the obviously correct stuff that is related to primitives or `vfs` objects. Hopefully this helps smoke out more path related bytes vs str issues in TortoiseHg. PyCharm seems smart enough to apply hints from annotated superclass functions, but pytype isn't (according to the *.pyi file generated), so those are annotated too. There was some discussion about changing the default path arg from `None` to `b''` in order to avoid the more verbose `Optional` declarations. This would be more in line with `os.path.join()` (which rejects `None`, but ignores empty strings), and still not change the behavior for callers still passing `None` (because the check is `if path` instead of an explicit check for `None`). But I didn't want to hold this up while discussing that, so this documents what _is_.

util: implement `writelines()` on atomictempfile With typehints on the vfs objects, pytype will flag this: FAILED: /mnt/c/Users/Matt/hg/.pytype/pyi/mercurial/patch.pyi /usr/bin/python3.8 -m pytype.single --imports_info /mnt/c/Users/Matt/hg/.pytype/imports/mercurial.patch.imports --module-name mercurial.patch -V 3.7 -o /mnt/c/Users/Matt/hg/.pytype/pyi/mercurial/patch.pyi --analyze-annotated --nofail --quick /mnt/c/Users/Matt/hg/mercurial/patch.py File "/mnt/c/Users/Matt/hg/mercurial/patch.py", line 535, in writerej: No attribute 'writelines' on mercurial.util.atomictempfile [attribute-error] In Union[ mercurial.util.atomictempfile, mercurial.vfs.checkambigatclosing, mercurial.vfs.delayclosedfile, mercurial.windows.fdproxy, mercurial.windows.mixedfilemodewrapper ] It's not a real problem there (atomictempfile is only created by passing different args), but it's reasonable for this to implement the function and behave like a normal file. There are other functions missing that can be added if/when needed.

typing: add basic type hints to localrepo.py There's a lot more that could be done, but this sticks to the obviously correct stuff that is either related to existing imports or primitives. Hopefully this helps smoke out more path related bytes vs str issues in TortoiseHg. I'm avoiding the interfaces for now, because they seem to confuse pytype and/or PyCharm. It might be worth typing the return of `makelocalrepository` to `localrepository`, but that leaks an implementation detail, so that can be revisited later.