rhg: Pass a &Config to Ui::new When a Ui object is needed to print errors about configuration-loading errors, an empty (default) configuration is used. Differential Revision: https://phab.mercurial-scm.org/D12164

rhg: Add support for HGPLAINEXPECT Differential Revision: https://phab.mercurial-scm.org/D12163

merge: with stable

help: make the help for `safe-mismatch` real section The extra new lines mean the minirst engine were not seeing them as section… meaning they could not be addressed directly. Differential Revision: https://phab.mercurial-scm.org/D12161

help: avoid repeated value in the safe-mistmatch help This was copy pasted and overlooked when it got in. Differential Revision: https://phab.mercurial-scm.org/D12160

help: add missing `.` in config reference The `hg help` command is still confused at the number of dots, but at least the reference is correct. Differential Revision: https://phab.mercurial-scm.org/D12159

scmutil: obsrevs is already a frozenset Differential Revision: https://phab.mercurial-scm.org/D12157

obsolete: always return frozensets from obsolete.getrevs() getrevs function already returns an empty frozenset when there is no obsstore, but let's make sure to return a frozenset in any case. This makes it possible to use the result of this function as a dict key or provide it to hash() built-in function without any conversions. Differential Revision: https://phab.mercurial-scm.org/D12156

revlog: split revlog v1 and revlog v2 handling Explicitly splitting their fields packing and unpacking makes it easier to extend the existing C implemenation to handle the new changelog format, whose fields and offsets are not simply a superset of the revlog. Differential Revision: https://phab.mercurial-scm.org/D12137

revlog: extract entry byte offsets into named constants Labelling the fields pointed by the given offsets shared by revlog v1 and v2. Differential Revision: https://phab.mercurial-scm.org/D12136