run-tests: add substitution patterns for common '\' path output on Windows The goal is to reduce the amount of hand tuning of new/changed tests that is required on Windows. Since the OS prints the proper paths everywhere else, this is limited to Windows. These are based on the check-code rules that were dropped in 5feb782c7a95. There are some minor tweaks, because those were trying to detect '/' paths without a '(glob)' at the end, whereas these detect '\' paths. Also, it looks like the 'no changes made to subrepo' one was broke, because the path to the subrepo has been getting output but was not in the pattern. End anchors are dropped because '(glob)' is no longer required, but '(feature !)' annotations are a possibility. The 'saved backup bundle' pattern dropped from run-tests.py was simply carrying over the first capture group. The replace() method runs prior to evaluating '\1', but it wasn't doing anything because of the 'r' prefix on '\\'. The 'not recording move' entry is new, because I stumbled upon it searching for some of these patterns. There are probably others.

debuginstall: add a line about re2 availability Using re2 engine can massively speed up regexp. We make it simpler to check if it is available in a given install.

tests: fix the check-code rule for testing non-existent files I missed this in feecfefeba25.

tests: convert the 'file://\$TESTTMP' rule to an automatic substitution The rule only triggered on non Windows platforms, even though Windows also required an adjustment. Automatic seems better. The aggressive globbing in test-subrepo-svn.t was found and rewritten by the substitution.

help: deprecate ui.slash in favor of slashpath template filter (issue5572) > For some reason, I thought someone (Mads?) said we had basically given > up on ui.slash, and some commands didn't support it. (from https://bz.mercurial-scm.org/show_bug.cgi?id=5572#c1) So the ui.slash option doesn't always work and is somewhat confusing. Let's make it clearer we won't improve the situation.

templatefilters: add slashpath() to convert path separator to slash Prepares for deprecating the ui.slash option, which isn't always respected.

check-code: remove unused variable 'winglobmsg' Follows up 5feb782c7a95.

phases: initialize number of loaded revisions to 0 As it isn't a revision number, an empty value should be 0, not -1.

phases: rename _phasemaxrev to _loadedrevslen to clarify it isn't max value "maxrev" sounds like max(0:tip), but it is actually len(0:tip).

lfs: add an experimental config to override User-Agent for the blob transfer This will allow developers to test against various server implementations. I didn't put it under [devel] because it's possible that some user needs to use it in the field.