merge with stable

branchmap: move validity logic in the object itself In several place, We check if a branchcache is still valid regarding the current state of the repository. This changeset puts this logic in a method of the object that can be reused when necessary. A branch map is considered valid whenever it is up to date or a strict subset of the repository state. The change will help making branchcache aware of filtered revision. The change in keyword is expected. the branch cache is actually invalid after the amend. The previous check did not detected it.

branchmap: make update a method

branchmap: make update responsible to update the cache key The update function have all necessary data to keep the branchcache key up to date with its value. This saves assignment to the cache key that each caller of update had to do by hand. The strip case is a bit more complicated to handles from inside the function but I do not expect any impact.

branchmap: factorise changelog access in update This both improves readability and performance. Access to changelog of filtered repository currently have a minor overhead.

branchmap: make write a method on the branchmap object

branchmap: simplify write signature All necessary data (cache value and key) are now stored in the branchcache object. Any extra parameter is superfluous.

branchmap: add the tiprev (cache key) on the branchmap object The actual cache key used on disk is the (tipnode, tiprev) pair. There is no reason not to use the revision number for the in memory version.

branchmap: add the tipnode (cache key) on the branchcache object Gathering data and cache key paves the way to a lot of simplification.

branchmap: store branchcache in a dedicated object Value and key of branchcache would benefit from being hold by the same object. Moreover some logic (update, write, validation) could be move on such object. The creation of this object is the first step toward this move. The result will clarify branchcache related code and hide most of the detail in the class itself. This encapsulation will greatly helps implementation of branchcache for filtered view of the repo.