annotate: reuse already calculated annotation
Before this patch, annotation is re-calculated even if it is already
calculated. This may cause unexpected annotation, because already
cleared "pcache" ("pcache[f] = []") prevents from scanning ancestors.
This patch reuses already calculated annotation if it is available.
In fact, "reusable" situation should be seen only on legacy
repositories in which a filelog include the merging between the
revision and its ancestor, because:
- tree is scanned in depth-first
without such merging, annotation result should be released soon
- recent Mercurial doesn't allow such merging
changelog and manifest can include such merging someway, but
filelogs can't, because "localrepository._filecommit()" converts
such merging request to linear history.
.. Common link and substitution definitions.
.. |hg(1)| replace:: **hg**\ (1)
.. _hg(1): hg.1.html
.. |hgrc(5)| replace:: **hgrc**\ (5)
.. _hgrc(5): hgrc.5.html
.. |hgignore(5)| replace:: **hgignore**\ (5)
.. _hgignore(5): hgignore.5.html