hgk: show secret changesets differently (shape and label)

manifestv2: implement slow readdelta() without revdiff For manifest v2, revlog.revdiff() usually does not provide enough information to produce a manifest. As a simple workaround, implement readdelta() by reading both the old and the new manifest and use manifest.diff() to find the difference. This is several times slower than the current readdelta() for v1 manifests, but there seems to be no other simple option, and this is still much faster than returning the full manifest (at least for verify).

manifestv2: disable fastdelta optimization We may add support for the fastdelta optimization for manifest v2 at a later point, but let's disable it for now, so we don't have to implement it right away.

manifestv2: add (unused) config option With tree manifests, hashes will change anyway, so now is a good time to also take up the old plans of a new manifest format. While there should be little or no reason to use tree manifests with the current manifest format (v1) once the new format (v2) is supported, we'll try to keep the two dimensions (flat/tree and v1/v2) separate. In preparation for adding a the new format, let's add configuration for it and propagate that configuration to the manifest revlog subclass. The new configuration ("experimental.manifestv2") says in what format to write the manifest data. We may later add other configuration to choose how to hash it, either keeping the v1 hash for BC or hashing the v2 content. See http://mercurial.selenic.com/wiki/ManifestV2Plan for more details.

manifest: extract method for creating manifest text Similar to the previous change, this one extracts a method for producing a manifest text from an iterator over (path, node, flags) tuples.

manifest: extract method for parsing manifest By extracting a method that generates (path, node, flags) tuples, we can reuse the code for parsing a manifest without doing it via a _lazymanifest like treemanifest currently does. It also prepares for parsing the new manifest format. Note that this makes parsing into treemanifest slower, since the parsing is now always done in pure Python. Since treemanifests will be expected (or even forced) to be used only with the new manifest format, parsing via _lazymanifest was not an option anyway.

dirstate._walkexplicit: don't bother normalizing '.' The overwhelmingly common case is running commands like 'hg diff' with no arguments. Therefore the only file that'll be listed is the root directory. Normalizing that's just a waste of time. This means that for a plain 'hg diff' we'll never need to construct the foldmap, saving us a significant chunk of time. On case-insensitive HFS+ on OS X, for a large repository with over 200,000 files, this brings down 'hg diff' from 2.97 seconds to 2.36.

dirstate._walkexplicit: drop normpath calls The paths the matcher returns are normalized already.

dirstate._walkexplicit: indicate root as '.', not '' '.' is the canonical way to represent the root, and it's apparently the only transformation that normpath makes.

phases: add killswitch for native implementation