treemanifest: allow manifestrevlog to take an explicit treemanifest arg Previously we relied on the opener options to tell the revlog to be a tree manifest. This makes it complicated for extensions to create treemanifests and normal manifests at the same time. Let's add a construtor argument to create a treemanifest revlog as well. I considered removing the options['treemanifest'] logic from manifestrevlog entirely, but doing so shifts the responsibility to the caller which ends up requiring changes in localrepo, bundlerepo, and unionrepo. I figured having the dual mechanism was better than polluting other parts of the code base with treemanifest knowledge.

policy: relax the default for in-place build We're going to make the 'c' policy more strict, where no missing attribute will be allowed. Since we want to run 'hg bisect' without rebuilding the C extension modules, we'll need a looser policy for development environment. The default for system installation isn't changed. Note that the current 'c' policy is practically 'allow'-ish as we have lots of adhoc fallbacks to pure functions.

verify: always check rawsize Previously, verify only checks "rawsize == len(rawtext)", if "len(fl.read()) != fl.size()". With flag processor, "len(fl.read()) != fl.size()" does not necessarily mean "rawsize == len(rawtext)". So we may miss a useful check. This patch removes the "if len(fl.read()) != fl.size()" condition so the rawsize check is always performed. With the condition removed, "fl.read(n)" looks unnecessary so a comment was added to explain the side effect is wanted.

rebase: rename "target" to "destination" in messages The help text for rebase calls it "the destination" (never "target"), so let's use that in messages as well.

rebase: rename "target" to "dest" in variable names It took me a while to figure out that "target" was actually what's passed to --dest.

sslutil: remove conditional cipher code needed for Python 2.6 We dropped support for Python 2.6. So this code to work around a missing feature on 2.6 is no longer necessary.

merge: use repo.wvfs.setflags() instead of util.setflags() Most merge.py code goes through the vfs instead of maniulating files directly, so let's do the same here.

merge with stable

revlog: move part of "addrevision" to "addrawrevision" "addrawrevision" will be the public API to reuse revision rawdata elsewhere. It will be used by a future patch.

filectx: add an overlayfilectx class The end goal is to make it possible to avoid potential expensive fctx.data() when unnecessary. While memctx is useful for creating new file contexts, there are many cases where we could reuse an existing raw file revision (amend, histedit, rebase, process a revision constructed by a remote peer, etc). The overlayfilectx class is made to support such reuse cases. Together with a later patch, hash calculation and expensive flag processor could be avoided.