bisect: build a displayer only once There is multiple spot using this, building it early will help to extract more of the logic into the bisect module.

bisect: factor commonly update sequence For now, This remains a closure in the module to avoid circular import with used module.

bisect: move check_state into the bisect module Now that the function is simpler, we resume our quest to move the logic into the bisect module. In the process, we add basic documentation.

bisect: simplify conditional in 'check_state' Now that extra code about "updating" flag have been removed, we can simplify the condition flow and remove a level.

bisect: remove code about "update-flag" in check_state Now that the flag dedicated to updating the flag are handled earlier, we do not need to handle them in the 'check_state' function.

bisect: rename 'check_code' to match our naming scheme We need to do it early, otherwise 'check-commit' will complain every time we touch it.

bisect: minor movement of code handle flag updating state The code flag handling is quite complicated, we are moving code around to prepare further simplification.

test-clone: discard lock-related messages We can't predict where those will show up and they're not super-important for the contents of this particular test, so just drop them. Further reduces the flakiness of the test to zero.

test-clone: fix some instability in pooled clone race condition test Healthy output (one log file mentioning "existing pooled" and one mentioning "new pooled") will now print in a stable order, but unhealthy output will print some sort of error. This reduces the flakiness of the test from 55% to 38%. My next patch makes it completely stable.

py3: add an os.fsencode backport to ease path handling

py3: a second argument to open can't be bytes This fixes open(filename, 'r'), open(filename, 'w'), etc. calls. In Python 3, that second argument *must* be a string, you can't use bytes. The fix is the same as used with getattr() (where the second argument must also always be a string); in the tokenizer, where we detect calls, if there is something that looks like a call to open (and is not an attribute, so the previous token is not a "." dot) then make sure that that second argument is not converted to a `bytes` object instead. There is some remaining issue where the current transformer will also rewrite open(f('foo')). However this also affect function for which we perform similar rewrite ('getattr', 'setattr', 'hasattr', 'safehasattr') and will be dealt with in a follow up.

py3: make check-py3-compat.py import importlib only if necessary importlib isn't available on Python 2.6, and it isn't necessary for Py2 checks.