extensions: use ui.log() interface to provide detailed loading information The output format changes and the messages will be sent to stderr instead of stdout, but I don't think that matters.

mq: implement log() on dummyui Otherwise ui.log() in extensions.py would explode.

ui: install logger that sends debug.extensions messages to stderr This will replace the custom log function introduced at d58958676b3c "extensions: add detailed loading information."

blackbox: resurrect recursion guard If I added ui.log() to hg.repository() function, test-merge-subrepos.t exploded. The problem is that the blackbox may create new repository instance while logging is active, and the created repository owns its new ui derived from the baseui, not from the ui which is processing the active logging. I tried to work around the issue in ui.log(), but that turned out to be not easy. We shouldn't globally lock the ui.log() since there may be more than one active repo/ui instances in threaded environment. We could store the logging state in thread-local storage, but that seems unnecessarily complex. So this patch reintroduces the _inlog flag to per-repository logger instances.

tests: filter out uninteresting log events This helps adding more log()s without updating the tests.

context: error out if basefilectx.cmp() is called without self._filenode The base implementation can't handle such cases because the filelog has no knowledge about the working directory. Loading self._filenode should have no extra cost since self.size() would load it anyway.

context: collapse complex condition to see if filelog have to be compared It's hard to read. I'd rather make the return statement duplicated.

merge with stable

worker: do not swallow exception occurred in main process Before, SystemExit(255) would be most likely raised since the worker processes were terminated by the main process and the status would be set to 255 in response. We should instead re-raise the exception occurred first. It's pretty hard to debug problems like the issue 6035 with no traceback.

run-tests: fix permission to clean up unreadable directories I found many hgtests.* directories left in $TMPDIR, which couldn't be deleted because test-ssh-repoerror.t created some directories with a-rx mode.

context: reimplement memfilectx.cmp() If I added a sanity check to basefilectx, test-context.py exploded. This patch copies the naive implementation from overlayworkingfilectx.

rust-cpython: build and support for Python3 Defined Cargo features for Python3, making them overall simpler to use, hooked them in build and made mercurial.rustext importable. This is tested with Python 3.6.7. Differential Revision: https://phab.mercurial-scm.org/D5446

py3: convert popen() command arguments in hgclient to str on Windows This fixes test-commandserver.t and test-keyword.t, which was previously complaining TypeError("a bytes-like object is required, not 'str'")

py3: byteify tests/pullext.py # skip-blame for b'' prepending

py3: byteify the fakeversion extension in test-http-bad-server.t # skip-blame for b'' prefixing

py3: spawn all python instances with legacy stdio enabled on Windows This fixes 6 more tests. See ef7119cd4965.