branchcache: add a "pure topological head" fast path
In a narrow but actually quick common case, all topological heads are all on
the same branch and all open. In this case, computing the branch map is very
simple. We can quickly detect situation where this situation will not change.
So we update the V3 format to be able to express this situation and upgrade the
update code to detect we remains in that mode.
The branch cache is populated with the actual value when the branch map is
accessed, but the update_disk method can do the update without needing to
populate it.
$ heads()
> {
> hg heads --template '{rev}: {desc|firstline|strip} ({branches})\n' "$@"
> }
$ hg init a
$ cd a
$ echo 'root' >root
$ hg add root
$ hg commit -m "Adding root node"
$ heads
0: Adding root node ()
-------
$ heads .
0: Adding root node ()
=======
$ echo 'a' >a
$ hg add a
$ hg branch a
marked working directory as branch a
(branches are permanent and global, did you want a bookmark?)
$ hg commit -m "Adding a branch"
$ heads
1: Adding a branch (a)
0: Adding root node ()
-------
$ heads .
1: Adding a branch (a)
=======
$ hg update -C 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo 'b' >b
$ hg add b
$ hg branch b
marked working directory as branch b
$ hg commit -m "Adding b branch"
$ heads
2: Adding b branch (b)
1: Adding a branch (a)
0: Adding root node ()
-------
$ heads .
2: Adding b branch (b)
=======
$ echo 'bh1' >bh1
$ hg add bh1
$ hg commit -m "Adding b branch head 1"
$ heads
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
$ heads .
3: Adding b branch head 1 (b)
=======
$ hg update -C 2
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo 'bh2' >bh2
$ hg add bh2
$ hg commit -m "Adding b branch head 2"
created new head
$ heads
4: Adding b branch head 2 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
$ heads .
4: Adding b branch head 2 (b)
3: Adding b branch head 1 (b)
=======
$ hg update -C 2
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo 'bh3' >bh3
$ hg add bh3
$ hg commit -m "Adding b branch head 3"
created new head
$ heads
5: Adding b branch head 3 (b)
4: Adding b branch head 2 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
$ heads .
5: Adding b branch head 3 (b)
4: Adding b branch head 2 (b)
3: Adding b branch head 1 (b)
=======
$ hg merge 4
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg commit -m "Merging b branch head 2 and b branch head 3"
$ heads
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
$ heads .
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
=======
$ echo 'c' >c
$ hg add c
$ hg branch c
marked working directory as branch c
$ hg commit -m "Adding c branch"
$ heads
7: Adding c branch (c)
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
$ heads .
7: Adding c branch (c)
=======
$ heads -r 3 .
no open branch heads found on branches c (started at 3)
[1]
$ heads -r 2 .
7: Adding c branch (c)
-------
$ hg update -C 4
0 files updated, 0 files merged, 2 files removed, 0 files unresolved
-------
$ heads -r 3 .
3: Adding b branch head 1 (b)
-------
$ heads -r 2 .
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
-------
$ heads -r 7 .
no open branch heads found on branches b (started at 7)
[1]
=======
$ for i in 0 1 2 3 4 5 6 7; do
> hg update -C "$i"
> heads
> echo '-------'
> heads .
> echo '-------'
> done
0 files updated, 0 files merged, 2 files removed, 0 files unresolved
7: Adding c branch (c)
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
0: Adding root node ()
-------
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
7: Adding c branch (c)
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
1: Adding a branch (a)
-------
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
7: Adding c branch (c)
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
-------
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
7: Adding c branch (c)
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
-------
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
7: Adding c branch (c)
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
-------
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
7: Adding c branch (c)
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
-------
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
7: Adding c branch (c)
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
-------
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
7: Adding c branch (c)
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
-------
7: Adding c branch (c)
-------
=======
$ for i in a b c z; do
> heads "$i"
> echo '-------'
> done
1: Adding a branch (a)
-------
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
-------
7: Adding c branch (c)
-------
abort: unknown revision 'z'
-------
=======
$ heads 0 1 2 3 4 5 6 7
7: Adding c branch (c)
6: Merging b branch head 2 and b branch head 3 (b)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
0: Adding root node ()
Topological heads:
$ heads -t
7: Adding c branch (c)
3: Adding b branch head 1 (b)
1: Adding a branch (a)
$ cd ..
______________
"created new head" message tests
$ hg init newheadmsg
$ cd newheadmsg
Init: no msg
$ echo 1 > a
$ hg ci -Am "a0: Initial root"
adding a
$ echo 2 >> a
$ hg ci -m "a1 (HN)"
$ hg branch b
marked working directory as branch b
(branches are permanent and global, did you want a bookmark?)
$ echo 1 > b
$ hg ci -Am "b2: Initial root for branch b"
adding b
$ echo 2 >> b
$ hg ci -m "b3 (HN)"
Case NN: msg
$ hg up -q null
$ hg branch -f b
marked working directory as branch b
$ echo 1 > bb
$ hg ci -Am "b4 (NN): new topo root for branch b"
adding bb
created new head
Case HN: no msg
$ echo 2 >> bb
$ hg ci -m "b5 (HN)"
Case BN: msg
$ hg branch -f default
marked working directory as branch default
$ echo 1 > aa
$ hg ci -Am "a6 (BN): new branch root"
adding aa
created new head
Case CN: msg
$ hg up -q 4
$ echo 3 >> bbb
$ hg ci -Am "b7 (CN): regular new head"
adding bbb
created new head
Case BB: msg
$ hg up -q 4
$ hg merge -q 3
$ hg branch -f default
marked working directory as branch default
$ hg ci -m "a8 (BB): weird new branch root"
created new head
Case CB: msg
$ hg up -q 4
$ hg merge -q 1
$ hg ci -m "b9 (CB): new head from branch merge"
created new head
Case HB: no msg
$ hg up -q 7
$ hg merge -q 6
$ hg ci -m "b10 (HB): continuing head from branch merge"
Case CC: msg
$ hg up -q 4
$ hg merge -q 2
$ hg ci -m "b11 (CC): new head from merge"
created new head
Case CH: no msg
$ hg up -q 2
$ hg merge -q 10
$ hg ci -m "b12 (CH): continuing head from merge"
Case HH: no msg
$ hg merge -q 3
$ hg ci -m "b12 (HH): merging two heads"
$ cd ..