narrow: drop support for remote expansion (BC) Previous patches to validate narrow patterns accidentically dropped support for the include: syntax that allows patterns to be expanded from a remote. This feature was never implemented in core and is only implemented on Google's custom server. Per @martinvonz's review comment in D4522, it is OK to drop this feature since it isn't used. The concept of this feature does seem useful. I anticipate it making a comeback some day in some shape or form. But for now, let's jettison the dead code. Differential Revision: https://phab.mercurial-scm.org/D4530

fastannotate: use repo.local() This is the proper way to check whether we're dealing with a local repository, since extensions should be coding to an interface and not testing for exact types. Differential Revision: https://phab.mercurial-scm.org/D4542

tests: drop extra "file:" prefix from paths in narrow test It looks like these were added by mistake in f4d4bd8c8911 (narrow: add a --narrowspec flag to clone command, 2018-08-08). Differential Revision: https://phab.mercurial-scm.org/D4531

narrow: validate spec files are well-formed during clone (BC) Previously, specfiles would get read then normalized. We want specfiles to be normalized on read so there is no confusion about what the format of specfiles should be. This commit validates the parsed result of --specfile. If entries aren't prefixed, an error is raised. Previously, validation would occur at exchange time, hence why we dropped a line of test output related to server iteraction. Differential Revision: https://phab.mercurial-scm.org/D4526

narrow: validate patterns on incoming bundle2 part The remote data is untrusted and needs to be validated for pattern conformance. Differential Revision: https://phab.mercurial-scm.org/D4525

narrowspec: validate patterns when loading and saving spec file Patterns should be normalized and validated before being passed into narrowspec.save(). Let's assert that by checking immediately before writing the narrow spec file. And let's assert that patterns loaded from the spec file also conform. Differential Revision: https://phab.mercurial-scm.org/D4524