osutil: implement __enter__ and __exit__ on posixfile So they can be used as context managers.

util: introduce ctxmanager, to avoid nested try/finally blocks This is similar in spirit to contextlib.nested in Python <= 2.6, but uses an extra level of indirection to avoid its inability to clean up if an __enter__ method raises an exception. Why add this mechanism? It greatly simplifies scoped resource management, and lets us eliminate several hundred lines of try/finally blocks. In many of these cases the "finally" is separated from the "try" by hundreds of lines of code, which makes the connection between resource acquisition and disposal difficult to follow. (The preferred mechanism would be the "multi-with" syntax of 2.7+, but Mercurial can't move to 2.7 for a while.) Intended use: >>> with ctxmanager(lambda: file('foo'), lambda: file('bar')) as c: >>> f1, f2 = c() This will open both foo and bar when c() is invoked, and will close both upon exit from the block. If the attempt to open bar raises an exception, the block will not be entered - but foo will still be closed.

hghave: support HGMODULEPOLICY for pure HGMODULEPOLICY was introduced in 4374d819ccd5

merge with stable

tests: extend check-commit self-tests This now contains both positive and negative tests for almost all the check-commit rules.

encoding: handle UTF-16 internal limit with fromutf8b (issue5031) Default builds of Python have a Unicode type that isn't actually full Unicode but UTF-16, which encodes non-BMP codepoints to a pair of BMP codepoints with surrogate escaping. Since our UTF-8b hack escaping uses a plane that overlaps with the UTF-16 escaping system, this gets extra complicated. In addition, unichr() for codepoints greater than U+FFFF may not work either. This changes the code to reuse getutf8char to walk the byte string, so we only rely on Python for unpacking our U+DCxx characters.

bmstore: add handling of the active bookmark This further centralizes the handling of bookmark storage, and will help get some lingering bookmarks business out of localrepo. Right now, this change implies reading of the active bookmark to also imply reading all bookmarks from disk - for users with many many bookmarks this may be a measurable performance hit. In that case, we should migrate bmstore to be able to lazy-read its properties from disk rather than having to eagerly read them, but I decided to avoid doing that to try and avoid some potentially complicated filecache decorator issues. This doesn't move the logic for writing the active bookmark into a transaction, though that is probably the correct next step. Since the API probably needs to morph a little more, I didn't bother marking bookmarks.{activate,deactivate} as deprecated yet.

patchbomb: treat empty address list as no addresses Previously it wasn't possible to use configuration to avoid being prompted for e.g. a CC list when using patchbomb to send emails. We now make it possible to supply an empty value.

config: add hasconfig method and supporting plumbing We add the hasconfig method to make it possible to distinguish between a config value that was never supplied and one that is empty.

verify: replace "output parameters" by return values _verifychangelog() and _verifymanifest() accept dictionaries that they populate. We pass in empty dictionaries, so it's clearer to create them in the functions and return them.