context: introduce an `isintroducedafter` method and use it in copies Right now, copy tracing make effort to not traverse the graph too much to save performance. It uses a "limit" acting as a floor revision past which data are no longer relevant to the current copy tracing. However, to enforce this limit, it does a call to `filectx.rev()` and that call can trigger a graph traversal on its own. That extra graph traversal is unaware of the current limit and can become very expensive. That cost is increased by the nature of work done in adjust link rev, we are not only walking down the graph, we are also checking the affected file for each revision we walk through. Something significantly more expensive than the walk itself. To work around this we need to make the `filectx` operation aware of the current limit. The first step is to introduce a dedicated method: `isintroducedafter`. We'll then rework that method logic to stop traversal as soon as possible.

context: take advantage of `_descendantrev` in introrev if available Before this changeset, `_descendantrev` was ignored and `introrev` could return a "wrong" result. I was previously fine because there seems to be no existing code using both `introrev` and `_descendantrev` at the same time. However, we would like to change that.

context: spell out the logic around linkrev adjustement starting point We make the intent of the `_changeid` and `_changectx` checks explicit. The same logic was previously performed by the `self.rev()` call. The new code is a bit redundant, but much clearer.

perf: add a new `perfhelper-tracecopies` command The command is not measuring performance itself, it digs interesting statistic to help pick good arguments for the `perfcopytrace` command.

narrow: extract helper for parsing narrowspec file This will be used for parsing a file that's stored in a different location. Differential Revision: https://phab.mercurial-scm.org/D5277

py3: cast attribute name to sysstr in clearcachedproperty()

py3: whitelist three more passing test caught by buildbot The number of failing test is back to two digits. Differential Revision: https://phab.mercurial-scm.org/D5293

tests: make test-check-module-imports more robust It failed for me without this in this way: tests/test-commandserver.t:19: relative import of stdlib module tests/test-lfs-serve.t:108: relative import of stdlib module tests/test-lfs-serve.t:255: relative import of stdlib module tests/test-lfs-serve.t:362: relative import of stdlib module tests/test-lfs-serve.t:406: relative import of stdlib module tests/test-lock.py:9: imports not lexically sorted: silenttestrunner < unittest, True, True tests/test-lrucachedict.py:5: imports not lexically sorted: silenttestrunner < unittest, True, True tests/test-match.py:5: imports not lexically sorted: silenttestrunner < unittest, True, True tests/test-remotefilelog-datapack.py:15: imports not lexically sorted: silenttestrunner < unittest, True, True tests/test-remotefilelog-histpack.py:14: imports not lexically sorted: silenttestrunner < unittest, True, True tests/test-simplekeyvaluefile.py:4: imports not lexically sorted: silenttestrunner < unittest, True, True tests/test-sshserver.py:6: imports not lexically sorted: silenttestrunner < unittest, True, True This is because every module is considered a stdlib module, because the stdlib_prefixes is /usr, and my repo is in /usr/local/home, which means that sys.path contains a couple of /usr/local/home/../hg/.. entries that count as "in the stdlib". Fix this by preventing any path in sys.path that's inside the mercurial source from being considered "in the stdlib". Differential Revision: https://phab.mercurial-scm.org/D5294

push: add --publish flag to change phase of pushed changesets This flag is copied from topic extension, where it proved to be useful. It makes all pushed changesets public on both ends if the push succeeds. Doesn't currently work for any subrepos that are implicitly pushed together with their owner repo.

match: reformat `syntaxes` dictionary for better maintainability