hooks: introduce a `:run-with-plain` option for hooks This option control if HGPLAIN should be set or not for the hooks. This is the first step to give user some control of the HGPLAIN setting for they hooks. Some hooks (eg: consistency checking) deserve to be run with HGPLAIN, some other (eg: user set visual helper) might need to respect the user config and setting. So both usage are valid and we need to restore the ability to run -without- HGPLAIN that got lost in Mercurial 5.7. This does not offer a way to restore the pre-5.7 behavior yet (respect whatever HGPLAIN setting from the shell), this will be dealt with in the next changeset. The option name is a bit verbose because implementing this highlighs the need for another option: `:run-if-plain`. That would make it possible for some hooks to be easily disabled if HG PLAIN is set. However such option would be a new feature, not something introduced to mitigate a behavior change introduced in 5.7, so the `:run-if-plain` option belong to the default branch and is not part of this series. Differential Revision: https://phab.mercurial-scm.org/D9981

hooks: add some test about HGPLAIN setting and hooks In Mercurial 5.7, hooks are now ran with HGPLAIN set, which is a behavior change in. I could not find explicit test about it so I am adding one. The next changesets will introduce more change to help user mitigate the behavior change when needed. Differential Revision: https://phab.mercurial-scm.org/D9979

hooks: forbid ':' in hook name The `:` character is a special separator in the config and it seems same do to the same for hooks. This is necessary to improve the experience around the HGPLAIN behavior change in 5.7. See next changesets for details. Differential Revision: https://phab.mercurial-scm.org/D9978

rust-status: honor matcher when using the dirstate-only fast-path (issue6483) Differential Revision: https://phab.mercurial-scm.org/D9977

status: add test that shows that the Rust implementation has a bug Differential Revision: https://phab.mercurial-scm.org/D9976

tweak-default: no longer enable the experimental return code The change is quite new and undocumented (since it is experimental) so it seems premature to make it available in tweak default. In addition, I am not sure the new return code are frozen yet (eg: some of the initial feedback have not been incorporated). Before the release I doubled check (probably with Martin) that they were not enabled by default and got replied that they were only enabled in the tests. Have I been aware that they have been also enabled in tweak default I would I have lobbied to delay that. I discovered they were in tweak default from users feedback. They found it an unpleasant and unexpected surprise of 5.7. So I suggest we no enable enable this experimental feature for Mercurial 5.7 and revisit this later, when the feature will be more mature. Differential Revision: https://phab.mercurial-scm.org/D9975

rhg: Parse per-repository configuration Differential Revision: https://phab.mercurial-scm.org/D9964

rhg: Abort based on config on share-safe mismatch Differential Revision: https://phab.mercurial-scm.org/D9963

rhg: Parse system and user configuration at program start … and pass it around up to `Repo::find` Differential Revision: https://phab.mercurial-scm.org/D9962

rust: Parse system and user configuration CLI `--config` argument parsing is still missing, as is per-repo config Differential Revision: https://phab.mercurial-scm.org/D9961