branchcache: skip entries that are topological heads in the on disk file
In the majority of cases, topological heads are also branch heads. We have
efficient way to get the topological heads and efficient way to retrieve
their branch information. So there is little value in putting them in the branch
cache file explicitly. On the contrary, writing them explicitly tend to create
very large cache file that are inefficient to read and update.
So the branch cache v3 format is no longer including them. This changeset focus
on the format aspect and have no focus on the performance aspect. We will cover
that later.
Set up repo
$ cat << EOF >> $HGRCPATH
> [ui]
> origbackuppath=.hg/origbackups
> [merge]
> checkunknown=warn
> EOF
$ hg init repo
$ cd repo
$ echo base > base
$ hg add base
$ hg commit -m "base"
Make a dir named b that contains a file, and a file named d
$ mkdir -p b
$ echo c1 > b/c
$ echo d1 > d
$ hg add b/c d
$ hg commit -m "c1"
$ hg bookmark c1
Peform an update that causes b/c to be backed up
$ hg up -q 0
$ mkdir -p b
$ echo c2 > b/c
$ hg up --verbose c1
resolving manifests
b/c: replacing untracked file
getting b/c
creating directory: $TESTTMP/repo/.hg/origbackups/b
getting d
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
(activating bookmark c1)
$ test -f .hg/origbackups/b/c
Make files named b and d
$ hg up -q 0
$ echo b1 > b
$ echo d2 > d
$ hg add b d
$ hg commit -m b1
created new head
$ hg bookmark b1
Perform an update that causes b to be backed up - it should replace the backup b dir
$ hg up -q 0
$ echo b2 > b
$ hg up --verbose b1
resolving manifests
b: replacing untracked file
getting b
removing conflicting directory: $TESTTMP/repo/.hg/origbackups/b
getting d
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
(activating bookmark b1)
$ test -f .hg/origbackups/b
Perform an update the causes b/c to be backed up again - it should replace the backup b file
$ hg up -q 0
$ mkdir b
$ echo c3 > b/c
$ hg up --verbose c1
resolving manifests
b/c: replacing untracked file
getting b/c
creating directory: $TESTTMP/repo/.hg/origbackups/b
removing conflicting file: $TESTTMP/repo/.hg/origbackups/b
getting d
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
(activating bookmark c1)
$ test -d .hg/origbackups/b
Cause two symlinks to be backed up that points to a valid location from the backup dir
$ hg up -q 0
$ mkdir ../sym-link-target
#if symlink
$ ln -s ../../../sym-link-target b
$ ln -s ../../../sym-link-target d
#else
$ touch b d
#endif
$ hg up b1
b: replacing untracked file
d: replacing untracked file
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
(activating bookmark b1)
#if symlink
$ readlink.py .hg/origbackups/b
.hg/origbackups/b -> ../../../sym-link-target
#endif
Perform an update that causes b/c and d to be backed up again - b/c should not go into the target dir
$ hg up -q 0
$ mkdir b
$ echo c4 > b/c
$ echo d3 > d
$ hg up --verbose c1
resolving manifests
b/c: replacing untracked file
d: replacing untracked file
getting b/c
creating directory: $TESTTMP/repo/.hg/origbackups/b
removing conflicting file: $TESTTMP/repo/.hg/origbackups/b
getting d
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
(activating bookmark c1)
$ cat .hg/origbackups/b/c
c4
$ cat .hg/origbackups/d
d3
$ ls ../sym-link-target
Incorrectly configure origbackuppath to be under a file
$ echo data > .hg/badorigbackups
$ hg up -q 0
$ mkdir b
$ echo c5 > b/c
$ hg up --verbose c1 --config ui.origbackuppath=.hg/badorigbackups
resolving manifests
b/c: replacing untracked file
getting b/c
creating directory: $TESTTMP/repo/.hg/badorigbackups/b
removing conflicting file: $TESTTMP/repo/.hg/badorigbackups
getting d
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
(activating bookmark c1)
$ ls .hg/badorigbackups/b
c