changegroup: fix treemanifests on merges The current code for generating treemanifest revisions takes the list of files in the changeset and finds the directories from them. This does not work for merges, since a merge may pick file A from one side and file B from another and neither of them would appear in the changeset's "files" list, but the manifest would still change. Fix this by instead walking the root manifest log for all needed revisions, storing all needed file and subdirectory revisions, then recursively visiting the subdirectories. This also turns out to be faster: cloning a version of hg core converted to treemanifests went from ~28s to ~19s (timing somewhat unfair: before this patch, timed until crash; after this patch, timed until manifests complete). The new algorithm is used only on treemanifest repos. Although it works equally well on flat manifests, we leave the iteration over files in the changeset for flat manifests for now.

templatekw: workaround for utf-8 round-trip of {desc} Though our encoding strategy is best effort, {desc} is a primitive keyword that should be worth enough to try hard to preserve UTF-8 bytes.

test: update test-bundle2-format.t comment Now that bundle2 is used by default for all exchanges, this comment is obviously out of date. Having deep testing of the API and expected behavior of the format and its processing is still valuable, so the comment is updated.

chg: extract gethgcmd logic to a function gethgcmd is to get original hg (not chg) binary name. This patch extracts the logic from execcmdserver to make it available for the following patch.

destutil: use cached branch information instead of query for efficiency Before this patch, calculation of "the tipmost branch head on current branch" uses revset query "max(.::(head() and branch(BRANCH)))", but this isn't efficiency, because: - head() predicate lists up heads on all branches, but - branch() predicate eliminates heads on other branches In addition to it, without "literal:" prefix for branch name, branch(BRANCH) tries to (1) look up BRANCH in "repo.branchmap()" and (2) look up BRANCH as symbol name again, if there is no branch matching against BRANCH. The latter looking up is obviously redundant. This patch uses repo.branchheads(closed=True) to get all branch heads on specified branch instead of "head() and branch(BRANCH)" revset query part. This patch also makes catching RepoLookupError meaningless, because it is only raised by revset predicate "branch()". But "currentbranch in repo.branchmap()" can detect whether currentbranch actually exists or not. Therefore, this patch replaces try/except for RepoLookupError by if/else for "currentbranch in repo.branchmap()".

destutil: replace wc.branch() invocations by cached value for efficiency

destutil: remove redundant examination Before this patch, "len(heads) != len(otherheads)" is examined to detect whether message should be displayed or not. But if "repo.revs('%ln and parents()', heads)", heads should contain "parents()" and otherheads is always less than heads.

destutil: add new local variable to increase readability Before this patch, local variable 'heads' is used not only for "all branch heads" but also for "branch heads other than current parent". This patch newly adds local variable 'otherheads' for the latter purpose, to increase readability.

changegroup: write root manifests and subdir manifests in a single loop This is another step towards making the manifest generation recurse along the directory trees. The loop over 'tmfnodes' now takes the form of a queue. At this point, we only add to the queue twice: we add the root manifests, and, while visiting the root manifest revisions, we add all subdirectory revisions (for treemanifest repos). Thus, any iterations over 'tmfnodes' after the first will not add any items and the "queue" will just keep shrinking.

changegroup: introduce makelookupmflinknode(dir) This is another step towards making the manifest generation recurse along the directory trees. It makes the two calls to _packmanifests() more similar.