rust-nodemap: accounting for dead blocks
By the very append-only nature of the `NodeTree`, inserting
new blocks has the effect of making some of the older ones
useless as they become unreachable.
Therefore some automatic housekeeping will need to be provided.
This is standard procedure in the word of databases, under names
such as "repack" or "vacuum".
The new `masked_readonly_blocks()` will provide callers with
useful information to decide if the nodetree is ripe for
repacking, but all the `NodeTree` can provide is how many
blocks have been masked in the currently mutable part. Analysing
the readonly part would be way too long to do it for each
transaction and defeat the whole purpose of nodemap persistence.
Serializing callers (from the Python layer) will get this figure
before each extraction and maintain an aggregate counter of
unreachable blocks separately.
Note: at this point, the most efficient repacking is just to restart
afresh with a full rescan.
Differential Revision: https://phab.mercurial-scm.org/D8097
$ . "$TESTDIR/narrow-library.sh"
$ hg init master
$ cd master
$ mkdir inside
$ echo inside > inside/f1
$ mkdir outside
$ echo outside > outside/f2
$ mkdir patchdir
$ echo patch_this > patchdir/f3
$ hg ci -Aqm 'initial'
$ cd ..
$ hg clone --narrow ssh://user@dummy/master narrow --include inside
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
new changesets dff6a2a6d433
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd narrow
$ mkdir outside
$ echo other_contents > outside/f2
$ hg tracked | grep outside
[1]
$ hg files | grep outside
[1]
$ hg status
`hg status` did not add outside.
$ hg tracked | grep outside
[1]
$ hg files | grep outside
[1]
Unfortunately this is not really a candidate for adding to narrowhg proper,
since it depends on some other source for providing the manifests (when using
treemanifests) and file contents. Something like a virtual filesystem and/or
remotefilelog. We want to be useful when not using those systems, so we do not
have this method available in narrowhg proper at the moment.
$ cat > "$TESTTMP/expand_extension.py" <<EOF
> import os
> import sys
>
> from mercurial import encoding
> from mercurial import extensions
> from mercurial import localrepo
> from mercurial import match as matchmod
> from mercurial import narrowspec
> from mercurial import patch
> from mercurial import util as hgutil
>
> narrowspecexpanded = False
> def expandnarrowspec(ui, repo, newincludes=None):
> if not newincludes:
> return
> if getattr(repo, '_narrowspecexpanded', False):
> return
> repo._narrowspecexpanded = True
> import sys
> newincludes = set([newincludes])
> includes, excludes = repo.narrowpats
> currentmatcher = narrowspec.match(repo.root, includes, excludes)
> includes = includes | newincludes
> if not repo.currenttransaction():
> ui.develwarn(b'expandnarrowspec called outside of transaction!')
> repo.setnarrowpats(includes, excludes)
> narrowspec.copytoworkingcopy(repo)
> newmatcher = narrowspec.match(repo.root, includes, excludes)
> added = matchmod.differencematcher(newmatcher, currentmatcher)
> for f in repo[b'.'].manifest().walk(added):
> repo.dirstate.normallookup(f)
>
> def reposetup(ui, repo):
> class expandingrepo(repo.__class__):
> def narrowmatch(self, *args, **kwargs):
> with repo.wlock(), repo.lock(), repo.transaction(
> b'expandnarrowspec'):
> expandnarrowspec(ui, repo,
> encoding.environ.get(b'DIRSTATEINCLUDES'))
> return super(expandingrepo, self).narrowmatch(*args, **kwargs)
> repo.__class__ = expandingrepo
>
> def extsetup(unused_ui):
> def overridepatch(orig, ui, repo, *args, **kwargs):
> with repo.wlock():
> expandnarrowspec(ui, repo, encoding.environ.get(b'PATCHINCLUDES'))
> return orig(ui, repo, *args, **kwargs)
>
> extensions.wrapfunction(patch, b'patch', overridepatch)
> EOF
$ cat >> ".hg/hgrc" <<EOF
> [extensions]
> expand_extension = $TESTTMP/expand_extension.py
> EOF
Since we do not have the ability to rely on a virtual filesystem or
remotefilelog in the test, we just fake it by copying the data from the 'master'
repo.
$ cp -a ../master/.hg/store/data/* .hg/store/data
Do that for patchdir as well.
$ cp -a ../master/patchdir .
`hg status` will now add outside, but not patchdir.
$ DIRSTATEINCLUDES=path:outside hg status
M outside/f2
$ hg tracked | grep outside
I path:outside
$ hg files | grep outside > /dev/null
$ hg tracked | grep patchdir
[1]
$ hg files | grep patchdir
[1]
Get rid of the modification to outside/f2.
$ hg update -C .
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
This patch will not apply cleanly at the moment, so `hg import` will break
$ cat > "$TESTTMP/foo.patch" <<EOF
> --- patchdir/f3
> +++ patchdir/f3
> @@ -1,1 +1,1 @@
> -this should be "patch_this", but its not, so patch fails
> +this text is irrelevant
> EOF
$ PATCHINCLUDES=path:patchdir hg import -p0 -e "$TESTTMP/foo.patch" -m ignored
applying $TESTTMP/foo.patch
patching file patchdir/f3
Hunk #1 FAILED at 0
1 out of 1 hunks FAILED -- saving rejects to file patchdir/f3.rej
abort: patch failed to apply
[255]
$ hg tracked | grep patchdir
[1]
$ hg files | grep patchdir > /dev/null
[1]
Let's make it apply cleanly and see that it *did* expand properly
$ cat > "$TESTTMP/foo.patch" <<EOF
> --- patchdir/f3
> +++ patchdir/f3
> @@ -1,1 +1,1 @@
> -patch_this
> +patched_this
> EOF
$ PATCHINCLUDES=path:patchdir hg import -p0 -e "$TESTTMP/foo.patch" -m message
applying $TESTTMP/foo.patch
$ cat patchdir/f3
patched_this
$ hg tracked | grep patchdir
I path:patchdir
$ hg files | grep patchdir > /dev/null