setup: drop support for Python 2.6 (BC) Per discussion on the mailing list and elsewhere, we've decided that Python 2.6 is too old to continue supporting. We keep accumulating hacks/fixes/workarounds for 2.6 and this is taking time away from more important work. So with this patch, we officially drop support for Python 2.6 and require Python 2.7 to run Mercurial.

perf: move revlog construction and length calculation out of benchmark We don't need to measure the time it takes to open the revlog or calculate its length. This is more consistent with what other perf* functions do. While I was here, I also renamed the revlog variable from "r" to "rl" - again in the name of consistency.

perf: clear revlog caches on every iteration cmdutil.openrevlog() may return a cached revlog instance. This /may/ be a recent "regression" due to refactoring of the manifest API. I'm not sure. Either way, this perf command was broken for at least manifests because subsequent invocations of the perf function would get cache hits from previous invocations, invalidating results. In the extreme case, testing the last revision in the revlog resulted in near-instantanous execution of subsequent runs (since the fulltext is cached). A time of ~1us would be reported in this case.

perf: don't convert rev to node before calling revlog.revision()

revlog: rename _chunkraw to _getsegmentforrevs() This completes our rename of internal revlog methods to distinguish between low-level raw revlog data "segments" and higher-level, per-revision "chunks." perf.py has been updated to consult both names so it will work against older Mercurial versions.

perf: store reference to revlog._chunkraw in a local variable To prepare for renaming revlog._chunkraw, we stuff a reference to this metho in a local variable. This does 2 things. First, it moves the attribute lookup outside of a loop, which more accurately measures the time of the code being invoked. Second, it allows us to alias to different methods depending on their presence (perf.py needs to support running against old Mercurial versions). Removing an attribute lookup from a tigh loop appears to shift the numbers slightly with mozilla-central: $ hg perfrevlogchunks -c ! read ! wall 0.354789 comb 0.340000 user 0.330000 sys 0.010000 (best of 28) ! wall 0.335932 comb 0.330000 user 0.290000 sys 0.040000 (best of 30) ! read w/ reused fd ! wall 0.342326 comb 0.340000 user 0.320000 sys 0.020000 (best of 29) ! wall 0.332857 comb 0.340000 user 0.290000 sys 0.050000 (best of 30) ! read batch ! wall 0.023623 comb 0.020000 user 0.000000 sys 0.020000 (best of 124) ! wall 0.023666 comb 0.020000 user 0.000000 sys 0.020000 (best of 125) ! read batch w/ reused fd ! wall 0.023828 comb 0.020000 user 0.000000 sys 0.020000 (best of 124) ! wall 0.023556 comb 0.020000 user 0.000000 sys 0.020000 (best of 126)

revlog: rename internal functions containing "chunk" to use "segment" Currently, "chunk" is overloaded in revlog terminology to mean multiple things. One of them refers to a segment of raw data from the revlog. This commit renames various methods only used within revlog.py to have "segment" in their name instead of "chunk." While I was here, I also made the names more descriptive. e.g. "_loadchunk()" becomes "_readsegment()" because it actually does I/O.

fsmonitor: do not nuke dirstate filecache In the future, chg may prefill repo's dirstate filecache so it's valuable and should be kept. Previously we drop both filecache and property cache for dirstate during fsmonitor reposetup, this patch changes it to only drop property cache but keep the filecache.

perf: move gettimer() call This is more consistent with other perf* functions.

perf: don't clobber startrev variable Previously, the "startrev" argument would be ignored due to "startrev = 0" in the benchmark function. This meant that `hg perfrevlog` always started at revision 0. Rename the local variable to "beginrev" so the variable does the right thing.

bundle: add optional 'tagsfnodecache' data to on disk bundle (issue5543) This should help performance when unbundling.

bundle2: move tagsfnodecache generation in a generic function This will help us reusing the logic for `hg bundle`.

bundle: introduce an higher level function to write bundle on disk The current function ('writebundle') is focussing on getting an existing changegroup to disk. It is no easy ways to includes more part in the generated bundle2. So we introduce a slightly higher level function that is fed the 'outgoing' object (that defines the bundled spec) and the bundlespec parameters (to control the changegroup generation and inclusion of other parts). This is creating the third logic dedicated to create a consistent bundle2 (the other 2 are the push code and the getbundle code). We should probably reconcile them at some points but they all takes different types of input. So we need to introduce an intermediate "object" that each different input could be converted to. Such unified "bundle2 specification" could be fed to some unified code. We start by having the `hg bundle` related code on its own to helps defines its specific needs first. Once the common and specific parts of each logic will be known we can start unification.

bundle: handle compression earlier We can also handle that part before starting any generation.

bundle: check changegroup version earlier We can check if we know how to bundle this changegroup version before actually starting to generate the changegroup.

bundle: check lack of revs to bundle before generating the changegroup We already have the information so we can check it earlier.

extdiff: copy back files to the working directory if the size changed In theory, it should be enough to pay attention only to the modification time when detecting if a snapshotted working directory file changed. In practice, BeyondCompare preserves all file attributes when syncing files at the directory level. (If you open the file and sync individual hunks, then mtime does change, and everything was being copied back as desired.) I'm not sure how many other synchronization tools would trigger this issue, but it's annoyingly inconsistent (if a single file is diffed, it isn't snapshotted, so the same BeyondCompare file sync operation _is_ visible, because wdir() is updated in place. I filed a bug with them, and they stated it is on their wish list, but won't be fixed in the near term. This isn't a complete fix (there is still the case of the size not changing), but this seems like a trivial enough change to fix most of the problem. I suppose we could fool around with making files in the other snapshot readonly, and copy back if we see the readonly bit copied. That seems pretty hacky though, and only works if the external tool copies all attributes.

test-extdiff: enable a previously failing test on Windows

test-extdiff: narrow the range of an '#if execbit' block Now that output can be conditionalized, the few `chmod +x` specific outputs can be conditionalized, and the rest of the tests run as normal. Disable one test that is failing on Windows for now.

test-extdiff: deduplicate tests

test-extdiff: fill in a missing Windows test

policy: eliminate ".pure." from module name only if marked as dual So we can switch cext/pure modules to new layout one by one.

policy: add "cext" package which will host CPython extension modules I'm going to restructure cext/pure modules and get rid of our hgimporter hack. C extension modules will be moved to cext/ directory so old and new compiled modules can coexist in development tree. This is necessary to run 'hg bisect' without recompiling. New extension modules will be loaded by an importer function: base85 = policy.importmod('base85') # select pure.base85 or cext.base85 This will also allow us to split cffi from pure modules, which is currently difficult because pure modules can't be imported by name.

policy: mark all string literals as sysstr or bytes The policy module won't be imported early in future, which means string literals will be processed by our Python 3 loader.

debuginstall: check C extensions only if they are loadable per policy This check is useless in pure installation and I want to make it directly import C extension modules.

osutil: proxy through util (and platform) modules (API) See the previous commit for why. Marked as API change since osutil.listdir() seems widely used in third-party extensions. The win32mbcs extension is updated to wrap both util. and windows. aliases.

win32mbcs: wrap underlying pycompat.bytestr to use checkwinfilename safely win32mbcs wraps some functions, to prevent them from unintentionally treating backslash (0x5c), which is used as the second or later byte of multi bytes characters by problematic encodings, as a path component delimiter on Windows platform. This wrapping assumes that wrapped functions can safely accept unicode string arguments. Unfortunately, d1937bdcee8c broke this assumption by introducing pycompat.bytestr() into util.checkwinfilename() for py3 support. After that, wrapped checkwinfilename() always fails for non-ASCII filename at pycompat.bytestr() invocation. This patch wraps underlying pycompat.bytestr() function to use util.checkwinfilename() safely. To avoid similar regression in the future, another patch series will add smoke testing on default branch.

hghave: prefill more version of Mercurial The previous code was unable to go above version 4.0.

graft: fix graft across merges of duplicates of grafted changes Graft used findmissingrevs to find the candidates for graft duplicates in the destination. That function operates with the constraint: 1. N is an ancestor of some node in 'heads' 2. N is not an ancestor of any node in 'common' For our purpose, we do however have to work correctly in cases where the graft set has multiple roots or where merges between graft ranges are skipped. The only changesets we can be sure doesn't have ancestors that are grafts of any changeset in the graftset, are the ones that are common ancestors of *all* changesets in the graftset. We thus need: 2. N is not an ancestor of all nodes in 'common' This change will graft more correctly, but it will also in some cases make graft slower by making it search through a bigger and unnecessary large sets of changes to find duplicates. In the general case of grafting individual or linear sets, we do the same amount of work as before.

graft: test coverage of grafts and how merges can break duplicate detection This demonstrates unfortunate behaviour: extending the graft range cause the graft to behave differently. When the graft range includes a merge, we fail to detect duplicates that are ancestors of the merge.