copies: do full filtering at end of _changesetforwardcopies()
As mentioned earlier, pathcopies() is very slow when copies are stored
in the changeset. Most of the cost comes from calling _chain() for
every changeset, which is slow because it needs to read manifests. It
needs to read manifests to be able to filter out copies that are were
created in one commit and then deleted. (It also filters out copies
that were created from a file that didn't exist in the starting
revision, but that's a fixed revision across calls to _chain(), so
it's much cheaper.)
This patch changes from _chainandfilter() to just _chain() in the main
loop in _changesetforwardcopies(). It instead removes copies that have
subsequently been removed by using ctx.filesremoved(). We thus rely on
that to be fast.
It timed this command in mozilla-unified:
hg debugpathcopies FIREFOX_59_0b3_BUILD2 FIREFOX_BETA_59_END
It took 18s before and 1.1s after. It's still faster when copy
information is stored in filelogs: 0.70s. It also still gets slow when
there are merge commits involved, because we read manifests there
too. We'll deal with that later.
Differential Revision: https://phab.mercurial-scm.org/D6419
basic:
* neither file exists
creating
* neither file still exists
* empty file x created
creating
* file x changed size
creating
* nothing changed with either file
* file x changed inode
creating
* empty file y created
creating
* file y changed size
creating
* file y changed inode
creating
* both files changed inode
creating
fakeuncacheable:
* neither file exists
creating
* neither file still exists
creating
* empty file x created
creating
* file x changed size
creating
* nothing changed with either file
creating
* file x changed inode
creating
* empty file y created
creating
* file y changed size
creating
* file y changed inode
creating
* both files changed inode
creating
repository tip rolled back to revision -1 (undo commit)
working directory now based on revision -1
repository tip rolled back to revision -1 (undo commit)
working directory now based on revision -1
setbeforeget:
* neither file exists
string set externally
* file x created
creating
string from function
* string set externally again
string 2 set externally
* file y created
creating
string from function
antiambiguity: