rust-index: don't use mutable borrow for head-diff computation It does not needs to mutate the index. This is one of the two suspects of RuntimeError being thrown during push.

branchcache: move head writing in a `_write_headers` method Same rational: this will help having format variants.

branchcache: move head writing in a `_write_heads` method Same rational: this will help having format variants.

branchcache: move the header loading in a `_load_header` class method This will help changing header parsing in format variants.

branchcache: simplify a long line Gratuitous change to help code readability.

branchcache: rename `load` to `_load_heads` We are about to have more similar function, we rename the existing one to a more meaningful name and mark it private in the process.

branchcache: move the filename to a class attribute This prepare the introduction of more variant of cache.

test-clonebundles: simplify matching to be less flavor depends We keep the files and bytes output for the first call, but then we mostly check that we are being served a stream-clone bundle, not the actual content and size of the bundle. That aspect being tested by the stream clone test themselves.

repoview: fix changelog.__contains__ method This have been around for ten years, so we can safely that this method have few callers. However I am about to add one.

branchcache: unconditionally write delayed branchmap

branchcache: drop the unused `_verifyclosed` This code appears dead since its introduction about 5 years ago in this three consecutive commits: - 6578654916ae → introduce the method with two calls - 7c9d4cf23adf → remove first call - be5eeaf5c24a → remove second call o changeset: be5eeaf5c24a | user: Pulkit Goyal <pulkit@yandex-team.ru> | date: Fri Apr 05 15:57:09 2019 +0300 | summary: branchcache: don't verify closed nodes in _branchtip() | o changeset: 7c9d4cf23adf | user: Pulkit Goyal <pulkit@yandex-team.ru> | date: Fri Apr 05 15:56:33 2019 +0300 | summary: branchcache: don't verify closed nodes in iteropen() | o changeset: 6578654916ae | user: Pulkit Goyal <pulkit@yandex-team.ru> ~ date: Mon Apr 01 13:56:47 2019 +0300 summary: branchcache: lazily validate nodes from the branchmap

branchcache: dispatch the code into the dedicated subclass The code useful only to the local brancache have now been moved into the dedicated subclass. This will help improving the branchcache code without subtle breaking the remote variants.

branchcache: introduce a base class for branchmap This will help define a clear boundary between the two.

branchcache: fix the copy code We copy some internal attribute along too. This should prevent inconsistency in the resulting branchmap.

branchcache: pass a "verify_node" attribut to __init__ instead of hasnode The hasnode callback cannot be inherited and is dropped on copy, which seems like a bad idea. Instead we pass the actual semantic as a parameter and let the internal logic deal with it.