localrepo: move extension loading to a separate method The stateful chg plan [1] requires a special repo object, where ideally all side effects caused by loading the repo object could be reverted by just dropping (gabbage collect) the loaded repo object. Currently, that is impossible because repo.__init__ calls "extensions.loadall", which may have unpredictable side-effects that cannot be reverted by dropping the repo object. This patch moves "extensions.loadall" to a separate method, so chg could subclass localrepository and make extensions loading a no-op. [1]: mercurial-scm.org/pipermail/mercurial-devel/2017-February/092547.html

py3: convert the mode argument of os.fdopen to unicodes Couple of these from the earlier series got lost while rebasing. So this patch converts them again.

runtests: unindent an "if True" block The block was left to make review easier. This patch unindents it.

runtests: set web.ipv6 if we use IPv6 As explained by the previous patch, we need to set "web.ipv6=True" if we decide to use IPv6. Otherwise "hg serve" will still try to listen on IPv4. This patch makes it so by appending web.ipv6 to "extra configs". This patch was tested in a Linux system with IPv6, by the following steps: 1. Change hgweb/server.py temporarily to write a file if IPv6HTTPServer.__init__ is called. 2. run-tests.py -l --keep-tmpdir test-serve.t 3. Check the generated .hgrc, make sure it sets web.ipv6=1. 4. Check the log file to make sure IPv6HTTPServer.__init__ is called.

runtests: checkportisavailable should only check one family As explained by the previous patch, checkportisavailable() should only check the preferred family - either IPv4 or IPv6, not both. This patch makes it so.

runtests: add a function to test if IPv6 is available Previously, checkportisavailable returns True if the port is free either on IPv4 or IPv6, but the hg server only uses IPv4 by default. That leads to issues when IPv4 port is not free but the IPv6 one is. To address that, run-tests should stick with either IPv4 or IPv6. This patch adds a function similar to checkportisavailable to test if IPv6 is available, and assigns the result to a variable. The new function was tested in a Linux system script with the following steps: 1. Run "ip addr del ::1/128 dev lo" to delete lo's IPv6 address, Confirm checkipv6available() returns False. 2. Run "ip addr add ::1/128 dev lo" to add back lo's IPv6 address. Confirm checkipv6available() returns True. 3. Start a web server taking the 8000 port. Confirm checkipv6available(8000) is still True.

histedit: log the time taken to read in the commands list If we're being fed an external command list from stdin (histedit --commands -), then the time spent reading stdin is outside our control. Log it.

extdiff: log time spent in external diff program We can't fix the time external diff programs take to run. Log that duration for us to remove from any stats we gather

crecord: log blocked time waiting for curses input We want to know when we're blocked waiting for the user - log the time spent waiting in the curses keyboard handlers

ui: give editor() a tag of its own We know that calls to ui.editor() always block on the user's configured editor. Use a blocking tag that ensures that we don't see a huge variety of editor options in our logging.