bookmarks: actual fix for race condition deleting bookmark This is a simple but efficient fix to prevent the issue tested in `test-bookmarks-corner-case.t`. It might be worth pursuing a more generic approach where filecache learn to depend on each other, but that would not be suitable for stable. The issue is complicated enough that I documented the race and its current solution as inline comment. See this comment for details on the fix.

strip: access bookmark before getting a reference to changelog Bookmark access might invalidate the current changelog (to make sure both are in a reasonable synchronisation state). So we should grab the reference to changelog after we access bookmark. Otherwise we risk using a dead object for the whole strip process. (note: this dead object business probably requires a new layers of checking)

test: use a more verbose output in the test While debugging some test failure, I released the test never checks if the relevant changesets were preserved. So I am updating the test from `hg parents` usage to `hg log -G` with a special template. This increase the area covered by the test and clarify the test failures.

byteify-strings: simplify default value for `--treat-as-kwargs`

byteify-strings: add --treat-as-kwargs argument to handle kwargs-like objects This argument will help extensions move to Python 3 as keyword arguments should not be byte-prefixed. Most of the time, code bases will call this object `kwargs`, but other conventions exist like `opts`, so it should make sense to allow for custom names. This is a best effort solution that does minimal static checking; cases like `options = [o for o in ('a', 'b', 'c') if kwargs.get(o)]` and other just as complicated will not be detected.

byteify-strings: add helpers to check for item access or method call These helpers will be used in a future patch, split for ease of review.

byteify-strings: add support for ignore comments Our simple token analysis is sometimes not clever enough, we need to be able to turn off our script for parts of the code. This change introduces three special comments: - `#no-py3-transform` to tell `byteify-strings` ignore the next line - `#py3-transform: off` to ignore everything until the end of the file - `#py3-transform: on` to stop ignoring The last two can be particularly useful within Python 2/3 compatibility files.

byteify-strings: handle triple quoted strings if they are not docstrings As with anything in this script, this is a best effort approach. Most of the time, when a triple quoted string is assigned to something, it's not a docstring.

byteify-strings: handle multi-line strings in _ensuresysstr The current implementation did not handle calls like `repo.ui.log("first line" "other line")` correctly.

fix: run fixer tools in the repo root as cwd so they can use the working copy This lets fixer tools do things like find configuration files, with the caveat that they'll only see the version of that file in the working copy, regardless of what revisions are being fixed. Differential Revision: https://phab.mercurial-scm.org/D6440