library: enable runpy invocation on mercurial package

match: add `filepath:` pattern to match an exact filepath relative to the root It's useful in certain automated workflows to make sure we recurse in directories whose name conflicts with files in other revisions. In addition it makes it possible to avoid building a potentially costly regex, improving performance when the set of files to match explicitly is large. The benchmark below are run in the following configuration : # data-env-vars.name = mozilla-central-2018-08-01-zstd-sparse-revlog # benchmark.name = files # benchmark.variants.rev = tip # benchmark.variants.files = all-list-filepath-sorted # bin-env-vars.hg.flavor = no-rust It also includes timings using the re2 engine (through the `google-re2` module) to show how much can be saved by just using a better regexp engine. Pattern time (seconds) time using re2 ----------------------------------------------------------- just "." 0.4 0.4 list of "filepath:…" 1.3 1.3 list of "path:…" 25.7 3.9 list of patterns 29.7 10.4 As you can see, Without re2, using "filepath:" instead of "path:" is a huge win. With re2, it is still about three times faster to not have to build the regex.

path: use the next `display` argument to deal with boolean We have a generic mechanism that we can now use for the special case now.

path: display proper user facing value for pulled-delta-reuse-policy The integer was not what the user expect nor what could be provided as a config value.

paths: add an argument to format the suboption display We will use it in the next function to the delta policy display. It could also be use to deal with the other special case in the command code, but that is unnecessary churn for stable so that part will go on default.

ui: fix crash in `hg paths` when pulled-delta-reuse-policy is in use The crash is a result of [value] being an int, but being used as a bytestring.

ui: add a test demonstrating a crash in `hg paths`

re2: fix reporting of availability in `hg debuginstall` We add and use an official API to check is re2 is available. This prevent the bug previously in place were debuginstall was considering confusing `None` (i.e. non-initialized) and `False` (i.e. unavailable).

re: make _checkre2 a static method There is no need to it to be a method, so we make it at least a static method to make it easier to call.

re2: exit `_checkre2` early if calling it is useless If we already know if re2 is supported there is no need to run the check again. Stricly speaking we don't call it twice, but this seems a simple enough safeguard to include in this series.