annotate: increase refcount of each revisions correctly (issue3841)
Before this patch, refcount (managed in "needed") of parents of each
revisions in "visit" is increased, only when parent is not annotated
yet (examined by "p not in hist").
But this causes less refcount of the revision like "A" in the tree
below ("A" is assumed as the second parent of "C"):
A --- B --- C
\ /
\-----/
Steps of annotation for "C" in this case are shown below:
1. for "C"
1.1 increase refcount of "B"
1.2 increase refcount of "A" (=> 1)
1.3 defer annotation for "C"
2. for "A"
2.1 annotate for "A" (=> put result into "hist[A]")
2.2 clear "pcache[A]" ("pcache[A] = []")
3. for "B"
3.1 not increase refcount of "A", because "A not in hist" is False
3.2 annotate for "B"
3.3 decrease refcount of "A" (=> 0)
3.4 delete "hist[A]", even though "A" is still needed by "C"
3.5 clear "pcache[B]"
4. for "C", again
4.1 not increase refcount of "B", because "B not in hist" is False
4.2 increase refcount of "A" (=> 1)
4.3 defer annotation for "C"
5. for "A", again
5.1 annotate for "A" (=> put result into "hist[A]", again)
5.2 clear "pcache[A]"
6. for "C", once again
6.1 not increase refcount of "B", because "B not in hist" is False
6.2 not increase refcount of "A", because "A not in hist" is False
6.3 annotate for "C"
6.4 decrease refcount of "A", and delete "hist[A]"
6.5 decrease refcount of "B", and delete "hist[B]"
6.6 clear "pcache[C]"
At step (5.1), annotation for "A" mis-recognizes that all lines are
created at "A", because "pcache[A]" already cleared at step (2.2)
prevents from scanning ancestors of "A".
So, annotation for "C" or its descendants loses information about "A"
or its ancestors.
The root cause of this problem is that refcount of "A" is decreased at
step (3.3), even though it isn't increased at step (3.1).
To increase refcount correctly, this patch increases refcount of each
parents of each revisions:
- regardless of "p not in hist" or not, and
- only once for each revisions in "visit" (by "not pcached")
In fact, this problem should occur only on legacy repositories in
which a filelog includes the merging between the revision and its
ancestor (as the second parent), because:
- tree is scanned in depth-first
without such merging, revisions in "visit" refer different
revisions as parent each other
- 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.
This patch tests merging cases below: these cases are from filelog of
"mercurial/commands.py" in the repository of Mercurial itself.
- both parents are same
10 --- 11 --- 12
\_/
filelogrev: changesetid:
10 00ea3613f82c
11 fc4a6e5b5812
12 4f802588cdfb
- the second parent is also ancestor of the first one
37 --- 38 --- 39 --- 40
\________/
filelogrev: changesetid:
37 f8d56da6ac8f
38 38919e1c254d
39 d3400605d246
40 f06a4a3b86a7
$ cat > writepatterns.py <<EOF
> import sys
>
> path = sys.argv[1]
> patterns = sys.argv[2:]
>
> fp = file(path, 'wb')
> for pattern in patterns:
> count = int(pattern[0:-1])
> char = pattern[-1] + '\n'
> fp.write(char*count)
> fp.close()
> EOF
prepare repo
$ hg init a
$ cd a
These initial lines of Xs were not in the original file used to generate
the patch. So all the patch hunks need to be applied to a constant offset
within this file. If the offset isn't tracked then the hunks can be
applied to the wrong lines of this file.
$ python ../writepatterns.py a 34X 10A 1B 10A 1C 10A 1B 10A 1D 10A 1B 10A 1E 10A 1B 10A
$ hg commit -Am adda
adding a
This is a cleaner patch generated via diff
In this case it reproduces the problem when
the output of hg export does not
import patch
$ hg import -v -m 'b' -d '2 0' - <<EOF
> --- a/a 2009-12-08 19:26:17.000000000 -0800
> +++ b/a 2009-12-08 19:26:17.000000000 -0800
> @@ -9,7 +9,7 @@
> A
> A
> B
> -A
> +a
> A
> A
> A
> @@ -53,7 +53,7 @@
> A
> A
> B
> -A
> +a
> A
> A
> A
> @@ -75,7 +75,7 @@
> A
> A
> B
> -A
> +a
> A
> A
> A
> EOF
applying patch from stdin
patching file a
Hunk #1 succeeded at 43 (offset 34 lines).
Hunk #2 succeeded at 87 (offset 34 lines).
Hunk #3 succeeded at 109 (offset 34 lines).
a
created 189885cecb41
compare imported changes against reference file
$ python ../writepatterns.py aref 34X 10A 1B 1a 9A 1C 10A 1B 10A 1D 10A 1B 1a 9A 1E 10A 1B 1a 9A
$ diff aref a
$ cd ..