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.

ui: time calls to ui.system We want to know when we're blocked on ui.system, and why. Allow the user to supply a tag - otherwise we record on an unspecific tag derived from cmd.

ui: log time spent blocked on stdio We use a wrapper around Mercurial at Facebook that logs key statistics (like elpased time) to our standard performance tooling. This is less useful than it could be, because we currently can't tell when a command is slow because we need to fix Mercurial versus when a command is slow because the user isn't interacting quickly. Teach Mercurial to log the time it spends blocked, so that our tooling can pick it up and submit it with the elapsed time - we can then do the math in our tooling to see if Mercurial is slow, or if the user simply failed to interact. Combining this with the command duration log means that we can ensure that we concentrate performance efforts on the things that bite Facebook users. The perfwrite microbenchmark shifts from: Linux: ! wall 3.213560 comb 0.410000 user 0.350000 sys 0.060000 (best of 4) Mac: ! wall 0.342325 comb 0.180000 user 0.110000 sys 0.070000 (best of 20) before this change to: ! wall 3.478070 comb 0.500000 user 0.420000 sys 0.080000 (best of 3) Mac: ! wall 0.218112 comb 0.220000 user 0.150000 sys 0.070000 (best of 15) showing a small hit in comb time, but firmly in the noise on wall time.

contrib: add a write microbenchmark to perf.py I'm adding some performance logging to ui.write - this benchmark lets us confirm that the cost of that logging is acceptably low. At this point, the microbenchmark on Linux over SSH shows: ! wall 3.213560 comb 0.410000 user 0.350000 sys 0.060000 (best of 4) while on the Mac locally, it shows: ! wall 0.342325 comb 0.180000 user 0.110000 sys 0.070000 (best of 20)

ui: provide a mechanism to track and log blocked time We want to log the time Mercurial spends trapped in things outside programmatic control. Provide a mechanism to give us both command runtime and as many different sources of blocking as we deem useful.

mercurial: switch to util.timer for all interval timings util.timer is now the best available interval timer, at the expense of not having a known epoch. Let's use it whenever the epoch is irrelevant.

util: introduce timer() As documented for timeit.default_timer, there are better timers available for performance measures on some platforms. These timers don't have a set epoch, and thus are only useful for interval measurements, but have higher resolution, and thus get you a better measurement overall. Use the same selection logic as Python's timeit.default_timer. This is a platform clock on Python 2 and early Python 3, and time.perf_counter on Python 3.3 and later (where time.perf_counter is introduced as the best timer to use).

color: move the '_render_effects' function to the core module

color: move '_effect_str' function into the core module

color: move configstyles into the core module The extension is getting thinner as we speak!

color: rework conditional 'valideffect' Not very important, but the full conditional is not that hard to follow and having it unified make the function role a bit clearer in my opinion.

color: move 'valideffect' function into the core module

color: move '_terminfo_params' into the core 'color' module On step closer to have color in core.

color: move '_effect' mapping into core This is the second things we can move into core safely.

color: spread '_effect' values for readability We move to our "usual" one value per line style.

merge with stable

update: clarify that -C and -c are mutually exclusive This makes it clear in both the synopsis and in the verbose output that -C and -c are mutually exclusive. It also restructures the verbose output a little so it's better prepared for a third option (--merge). This patch also reorders the options to match the flag table.

update: move check for dirty wdir into hg.updatetotally() The function has a "check" parameter that's currently unused, and it makes sense to me to have it honor it. That way other callers than commands.update() could set it if they needed.

destutil: drop now-unused "check" parameter from destupdate()

destutil: remove duplicate check and leave it to merge.update() The check is done in merge.update() already and the next few patches will add more checks there. Some of the additional checks will need information about the merge that will not be available in destutil. Since commands.postincoming() catches UpdateAbort(), we need to change merge.update() to raise that more specific exception. This goes directly again 45b86dbabbda (destupdate: move the check related to the "clean" logic in the function, 2015-10-05), but it will simplify the next few patches, and we can always move it out again (preferably move, not copy) after if we still think it's better that way.

make: update .PHONY targets

debugcommands: move 'debugwireargs' in the new module

debugcommands: move 'debugwalk' in the new module