copies: move comment about implementation of mergecopies() to end When you start reading about mergecopies(), you want to know what it is, not that there are different implementations depending on config, so this patch moves that comment to the end. By the way, we don't seem to define what "copytracing" is. I'm just leaving it that way because I don't know what it is myself. It seems to be referred to only on mergecopies() (and not in pathcopies(), for example), so maybe "copytracing" is supposed to be exactly what mergecopies() does? Differential Revision: https://phab.mercurial-scm.org/D6235

remotefilelog: return expected type from copies overrides copies._computeforwardmissing() and copies._computenonoverlap() return sets, so the overrides should also do that. Differential Revision: https://phab.mercurial-scm.org/D6234

changelog: extract a _string_unescape() to mirror _string_escape() We use our own _string_escape() to encode the "extras" field. Then we use codecs.escape_decode() to escape it. But there's also a little workaround for dealing with escaped text that looks like octal numbers since the fix for https://bz.mercurial-scm.org/show_bug.cgi?id=3156. This patch extracts the call to codecs.escape_decode() along with the fix for octal numbers and puts it in a _string_unescape(). It also updates the test to check for the octal-number case from the aforementioned bug. As you may have suspected, I want to be able to reuse this new function later. Differential Revision: https://phab.mercurial-scm.org/D6184

copies: extract function for deciding whether to use changeset-centric algos We'll eventually have a "experimental.copies.read-from=changeset-only" option too and I don't want to spread the logic for determining if we should use changeset-centric of filelog-centric algorithms. Differential Revision: https://phab.mercurial-scm.org/D6163

getrenamedfn: get copy data from context object if configured The function returned from getrenamedfn() calls filelog.renamed(). That won't work when storing copy metadata in the changeset. I've just switched to a simple implementation here. We may or may not need to optimize it later, possibly by optimizing the callers. No more tests fail with "--extra-config-opt experimental.copies.read-from=compatibility)" than they did before this patch. Differential Revision: https://phab.mercurial-scm.org/D6162

branchmap: implement __contains__() We have good occurences of `if branch in branchmap()` in our code. If __contains__() is not implemented then it will use __iter__() to find whether the element exists or not which is not good. I am bit confused that whether I should move existing callers to hasbranch() or this patch is a good way. Differential Revision: https://phab.mercurial-scm.org/D6206

branchmap: prevent using __getitem__() in branchheads() branchheads() can directly use self._entries instead. Differential Revision: https://phab.mercurial-scm.org/D6205

branchmap: dynamically resolve type of branchcache class This is required to support subclassing. Thanks to Yuya for suggesting this in D6151. Differential Revision: https://phab.mercurial-scm.org/D6204

copies: print list of divergent renames in sorted order The current order is not obvious to the user (and I may change it in a later patch). Lexicographical order seems like the obvious choice here. Differential Revision: https://phab.mercurial-scm.org/D6227

import: suppress accept: header irccloud and others may perform content negotation and reject (406) if the accept header does not match the mime type of the object