perf: add perfchangegroupchangelog command This command can be used for testing the performance of producing the changelog portion of a changegroup. We could use additional perf* commands for testing other parts of changegroup. Those can be written another time, when they are needed. (And those may want to refactor the changegroup generation API so code can be reused.) Speaking of code reuse, yes, this command does reinvent a small wheel. I didn't want to scope bloat to change the changegroup API because that will invite bikeshedding.

perf: add --reverse to perfrevlog It can be useful to know how fast we can read revisions from a revlog in reverse. This operation tends to occur in `hg log` commands, for example.

log: copy the way of ancestor traversal to --follow matcher (issue5376) We can't use fctx.linkrev() because follow() revset tries hard to simulate the traversal of changelog DAG, not filelog DAG. This patch fixes _makefollowlogfilematcher() to walk file ancestors in the same way as revset._follow(). I'll factor out a common function in future patches.

log: unroll loop that populates file paths for --patch --follow matcher We can't handle the first fctx in the same manner as its ancestors. Also, I think the original code was too tricky.

wireproto: rename argument to groupchunks() groupchunks() is a generic "turn a file object into a generator" function. It isn't limited to changegroups. Rename the argument and update the docstring to reflect this.

tests: actually test non-generaldelta variant for stream clones 608cabec1b15 accidentally made both tests test generaldelta repos. Restore the test for a non-gd repo.

revlog: document high frequency of code execution Recording my notes while working on performance optimization.

revlog: make code in builddelta() slightly easier to read self.compress() is destructured into its components. "l" is renamed to "deltalen."

py3: update test expectation on stable

grep: rewrite help to better document current (confusing) behavior

templates: add built-in files() function We already support multiple primitive for listing files, which were affected by the current changeset. This patch adds files() which returns files of the current changeset matching a given pattern or fileset query via the "set:" prefix.

rebase: rebase changesets in topo order (issue5370) (BC) There are two reasons that rebase should be done this way: 1. This would make rebasing faster because it would minimize the total number of files to be checked out in the process, as it don't need to switch back and forth between branches. 2. It makes resolving conflicts easier as user has a better context. This commit changes the behavior in "Test multiple root handling" of test-rebase-obsolete.t. It is an expected change which reflects the new behavior that commits in a branch are grouped together when rebased.

dispatch: make hg --profile wrap reposetup Move profiling.maybeprofile() from _runcommand to _dispatch() so that profiler output will include reposetup.

dispatch: change indentation level in _dispatch() Add an if True: placeholder for a profiling context manager that will be added in the next commit, for the purpose of reducing size of the diff due to trivial indentation changes. This change should be a no-op.

log: drop outdated optimization to walk revisions in reverse order Since revset is computed lazily, there would be no (or little) benefit to reverse 'revs' temporarily.

graphlog: preserve topo sort even if additional filter options specified Use ordered=revset.followorder instead. This change is logically the same as fa5e4f58dfbc.

transaction: open a file with checkambig=True to avoid file stat ambiguity Before this patch, if steps below occurs at "the same time in sec", all of mtime, ctime and size are same between (1) and (3). 1. append data to revlog-style file (and close transaction) 2. discard appended data by truncation of rollback 3. append same size but different data to revlog-style file again Therefore, cache validation doesn't work after (3) as expected. To avoid file stat ambiguity around truncation, this patch opens a file with checkambig=True. This is a part of ExactCacheValidationPlan. https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan

repair: open a file with checkambig=True to avoid file stat ambiguity Before this patch, if steps below occurs at "the same time in sec", all of mtime, ctime and size are same between (1) and (3). 1. append data to revlog-style file (and close transaction) 2. discard appended data by truncation of strip 3. append same size but different data to revlog-style file again Therefore, cache validation doesn't work after (3) as expected. To avoid such file stat ambiguity around truncation, this patch opens a file with checkambig=True. This patch also introduces "with" statement style, to ensure immediate invocation of close() after truncation, because closing file is the only trigger to check (and get rid of) file stat ambiguity. This is a part of ExactCacheValidationPlan. https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan

changelog: specify checkambig=True to revlog.__init__, to avoid ambiguity If steps below occurs at "the same time in sec", all of mtime, ctime and size are same between (1) and (3). 1. append data to 00changelog.i (and close transaction) 2. discard appended data by truncation (strip or rollback) 3. append same size but different data to 00changelog.i again Therefore, cache validation doesn't work after (3) as expected. To avoid such file stat ambiguity around truncation, this patch specifies checkambig=True to revlog.__init__(). This makes revlog write changes out with checkambig=True. Even though changes of 00changelog.i themselves are written out at changelog._finalize(), this checkambig=True is needed, because revlog.checkinlinesize(), which is invoked at the end of changelog._finalize(), might replace already changed 00changelog.i by converted one. Even after this patch, avoiding file stat ambiguity of 00changelog.i around truncation isn't yet completed, because truncation side isn't aware of this issue. This is a part of ExactCacheValidationPlan. https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan

changelog: specify checkambig=True to avoid ambiguity around truncation If steps below occurs at "the same time in sec", all of mtime, ctime and size are same between (1) and (3). 1. append data to 00changelog.i (and close transaction) 2. discard appended data by truncation (strip or rollback) 3. append same size but different data to 00changelog.i again Therefore, cache validation doesn't work after (3) as expected. To avoid such file stat ambiguity around truncation, this patch specifies checkambig=True for renaming or opening to write changes out at finalization. Even after this patch, avoiding file stat ambiguity of 00changelog.i around truncation isn't yet completed, because truncation side isn't aware of this issue. This is a part of ExactCacheValidationPlan. https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan

manifest: specify checkambig=True to revlog.__init__, to avoid ambiguity If steps below occurs at "the same time in sec", all of mtime, ctime and size are same between (1) and (3). 1. append data to 00manifest.i (and close transaction) 2. discard appended data by truncation (strip or rollback) 3. append same size but different data to 00manifest.i again Therefore, cache validation doesn't work after (3) as expected. To avoid such file stat ambiguity around truncation, this patch specifies checkambig=True to revlog.__init__(). This makes revlog write changes out with checkambig=True. Even after this patch, avoiding file stat ambiguity of 00manifest.i around truncation isn't yet completed, because truncation side isn't aware of this issue. This is a part of ExactCacheValidationPlan. https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan

revlog: specify checkambig at writing to avoid file stat ambiguity This allows revlog-style files to be written out with checkambig=True easily. Because avoiding file stat ambiguity is needed only for filecache-ed manifest and changelog, this patch does: - use False for default value of checkambig - focus only on writing changes of index file out This patch also adds optional argument checkambig to _divert/_delay for changelog, to safely accept checkambig specified in revlog layer. But this argument can be fully ignored, because: - changes are written into other than index file, if name != target - changes are never written into index file, otherwise (into pending file by _divert, or into in-memory buffer by _delay) This is a part of ExactCacheValidationPlan. https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan

vfs: use checkambigatclosing in checkambig=True but atomictemp=False case In Mercurial source tree, opening a file in "a"/"a+" mode like below doesn't specify atomictemp=True for vfs, and this avoids file stat ambiguity check by atomictempfile. - writing changes out in revlog layer uses "a+" mode - truncation in repair.strip() uses "a" mode - truncation in transaction._playback() uses "a" mode If steps below occurs at "the same time in sec", all of mtime, ctime and size are same between (1) and (3). 1. append data to revlog-style file (and close transaction) 2. discard appended data by truncation (strip or rollback) 3. append same size but different data to revlog-style file again Therefore, cache validation doesn't work after (3) as expected. This patch uses checkambigatclosing in checkambig=True but atomictemp=False case, to check (and get rid of) file stat ambiguity at closing. This is a part of ExactCacheValidationPlan. https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan

scmutil: add file object wrapper class to check ambiguity at closing In Mercurial source tree, opening a file in "a"/"a+" mode like below doesn't specify atomictemp=True for vfs, and this avoids file stat ambiguity check by atomictempfile. - writing changes out in revlog layer uses "a+" mode - truncation in repair.strip() uses "a" mode - truncation in transaction._playback() uses "a" mode If steps below occurs at "the same time in sec", all of mtime, ctime and size are same between (1) and (3). 1. append data to revlog-style file (and close transaction) 2. discard appended data by truncation (strip or rollback) 3. append same size but different data to revlog-style file again Therefore, cache validation doesn't work after (3) as expected. This patch adds file object wrapper class checkambigatclosing to check (and get rid of) ambiguity at closing. It is used by vfs in subsequent patch. This is a part of ExactCacheValidationPlan. https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan BTW, checkambigatclosing is tested in test-filecache.py, even though it doesn't use filecache itself, because filecache assumes that file stat ambiguity never occurs (and there is no another test-*.py related to filecache).

scmutil: factor out common logic of delayclosedfile to reuse it This is a preparation for the subsequent patch, which adds another proxy class for a file object.

spartan: remove unused templates

monoblue: remove unused templates

gitweb: remove unused templates

paper: remove unused templates

help: add sections for revsets

help: move revsets.## documentation into infix section

help: clarify quotes are needed for filesets.size expressions