treemanifest: add walksubtrees api Adds a new function to treemanifest that allows walking over the directories in the tree. Currently it only accepts a matcher to prune the walk, but in the future it will also accept a list of trees and will only walk over subtrees that differ from the versions in the list. This will be useful for identifying what parts of the tree are new to this revision, which is useful when deciding the minimal set of trees to send to a client given that they have a certain tree already. Since this is intended for an extension to use, the only current consumer is a test. In the future this function may be useful for implementing other algorithms like diff and changegroup generation.

merge with stable

upgrade: drop the prefix to the '_finishdatamigration' function Now that we are in the 'upgrade' module we can simplify the name.

upgrade: drop the prefix to the '_filterstorefile' function Now that we are in the 'upgrade' module we can simplify the name.

upgrade: drop the prefix to the 'determineactions' function Now that we are in the 'upgrade' module we can simplify the name.

upgrade: drop the prefix to the 'findimprovements' function Now that we are in the 'upgrade' module we can simplify the name.

upgrade: drop the prefix to the 'supporteddestrequirements' function Now that we are in the 'upgrade' module we can simplify the name.

upgrade: drop the prefix to the 'allowednewrequirements' function Now that we are in the 'upgrade' module we can simplify the name.

upgrade: drop the prefix to the 'improvement' class Now that we are in the 'upgrade' module we can simplify the name.

upgrade: drop the prefix to the 'supportremovedrequirements' function Now that we are in the 'upgrade' module we can simplify the name.

upgrade: drop the prefix to the 'blocksourcerequirements' function Now that we are in the 'upgrade' module we can simplify the name.

upgrade: drop the prefix to the 'requiredsourcerequirements' function Now that we are in the 'upgrade' module we can simplify the name.

upgrade: extract code in its own module Given about 2/3 or 'mercurial.repair' is now about repository upgrade, I think it is fair to move it into its own module. An expected benefit is the ability to drop the 'upgrade' prefix of many functions. This will be done in coming changesets.

bundle2: move the 'close' method off the unpackermixin This method is unrelated to unpacking and only used by the unbundle20 class. We move it there for clarity.

bundle2: clarify the docstring of unpackermixin methods The unpackermixin is a utility used to implement the bundle2 protocol. It should not be used when writing part handlers. We update the docstring to clarify this.