evolve: fixing obscache invalidation This was missing a call to the parent's destroyed(), such that any transaction after stripping some nodes would result in a crash (by attempting to read nodes which were stripped).

obshashrange: warm the cache at the end of each transaction This will help having warmed cache for read only client. The warming is still imperfect in case of markers that trigger a reset, but we are in a better place than what we used to be.

obshashrange: warm cache outside of loops The performance impact will be lower

obshashrange: "update" the cache on each transaction close Right now the "update" does not really file the cache, but it will detect invalid situation and clean them.

obshashrange: properly invalidate the cache on destroyed Copy paste is the scurge of code source.

obshashrange: properly drop the current connection on clear

obshashrange: exit early if nothing to write

obshashrange: use the dualsourcecache as a base for the cache This will easily open the way to incrementally updated obshashrange cache. Small update are needed to the data base schema so be bump the version Currently the update function is not warming the cache (but details case where it is invalidated).

obscache: makes dualsourcecache compatible with obshashrange cache needs The goal of the abstract method is to be reusable. So we make sure it is reusable.

readme: add a changelog entry about the more efficient obscache

obscache: extract a data agnostic class We now have an independent class that we can reuse for other purpose (eg: obshashrange cache)

obscache: extract the actual data update in a dedicated function This will help extract a data agnostic class.

obscache: move an assert to a lower level

obscache: use 'nullid' as the hash of an empty obsstore This align this result with what we use for 'emptykey'