fastannotate: initial import from Facebook's hg-experimental
I made as few changes as I could to get the tests to pass, but this
was a bit involved due to some churn in the blame code since someone
last gave fastannotate any TLC.
There's still follow-up work here to rip out support for old versions
of hg and to integrate the protocol with modern standards.
Some performance numbers (all on my 2016 MacBook Pro with a 2.6Ghz i7):
Mercurial mercurial/manifest.py
traditional blame
time: real 1.050 secs (user 0.990+0.000 sys 0.060+0.000)
build cache
time: real 5.900 secs (user 5.720+0.000 sys 0.110+0.000)
fastannotate
time: real 0.120 secs (user 0.100+0.000 sys 0.020+0.000)
Mercurial mercurial/localrepo.py
traditional blame
time: real 3.330 secs (user 3.220+0.000 sys 0.070+0.000)
build cache
time: real 30.610 secs (user 30.190+0.000 sys 0.230+0.000)
fastannotate
time: real 0.180 secs (user 0.160+0.000 sys 0.020+0.000)
mozilla-central dom/ipc/ContentParent.cpp
traditional blame
time: real 7.640 secs (user 7.210+0.000 sys 0.380+0.000)
build cache
time: real 98.650 secs (user 97.000+0.000 sys 0.950+0.000)
fastannotate
time: real 1.580 secs (user 1.340+0.000 sys 0.240+0.000)
mozilla-central dom/base/nsDocument.cpp
traditional blame
time: real 17.110 secs (user 16.490+0.000 sys 0.500+0.000)
build cache
time: real 399.750 secs (user 394.520+0.000 sys 2.610+0.000)
fastannotate
time: real 1.780 secs (user 1.530+0.000 sys 0.240+0.000)
So building the cache is expensive (but might be faster with xdiff
enabled), but the blame results are *way* faster.
Differential Revision: https://phab.mercurial-scm.org/D3994
$ cat >> $HGRCPATH << EOF
> [extensions]
> fastannotate=
> [fastannotate]
> mainbranch=main
> EOF
$ hg init repo
$ cd repo
add or rename files on top of the master branch
$ echo a1 > a
$ echo b1 > b
$ hg commit -qAm 1
$ hg bookmark -i main
$ hg fastannotate --debug -nf b
fastannotate: b: 1 new changesets in the main branch
0 b: b1
$ hg fastannotate --debug -nf a
fastannotate: a: 1 new changesets in the main branch
0 a: a1
$ echo a2 >> a
$ cat > b << EOF
> b0
> b1
> EOF
$ hg mv a t
$ hg mv b a
$ hg mv t b
$ hg commit -m 'swap names'
existing linelogs are not helpful with such renames in side branches
$ hg fastannotate --debug -nf a
fastannotate: a: linelog cannot help in annotating this revision
1 a: b0
0 b: b1
$ hg fastannotate --debug -nf b
fastannotate: b: linelog cannot help in annotating this revision
0 a: a1
1 b: a2
move main branch forward, rebuild should happen
$ hg bookmark -i main -r . -q
$ hg fastannotate --debug -nf b
fastannotate: b: cache broken and deleted
fastannotate: b: 2 new changesets in the main branch
0 a: a1
1 b: a2
$ hg fastannotate --debug -nf b
fastannotate: b: using fast path (resolved fctx: True)
0 a: a1
1 b: a2
for rev 0, the existing linelog is still useful for a, but not for b
$ hg fastannotate --debug -nf a -r 0
fastannotate: a: using fast path (resolved fctx: True)
0 a: a1
$ hg fastannotate --debug -nf b -r 0
fastannotate: b: linelog cannot help in annotating this revision
0 b: b1
a rebuild can also be triggered if "the main branch last time" mismatches
$ echo a3 >> a
$ hg commit -m a3
$ cat >> b << EOF
> b3
> b4
> EOF
$ hg commit -m b4
$ hg bookmark -i main -q
$ hg fastannotate --debug -nf a
fastannotate: a: cache broken and deleted
fastannotate: a: 3 new changesets in the main branch
1 a: b0
0 b: b1
2 a: a3
$ hg fastannotate --debug -nf a
fastannotate: a: using fast path (resolved fctx: True)
1 a: b0
0 b: b1
2 a: a3
linelog can be updated without being helpful
$ hg mv a t
$ hg mv b a
$ hg mv t b
$ hg commit -m 'swap names again'
$ hg fastannotate --debug -nf b
fastannotate: b: 1 new changesets in the main branch
1 a: b0
0 b: b1
2 a: a3
$ hg fastannotate --debug -nf b
fastannotate: b: linelog cannot help in annotating this revision
1 a: b0
0 b: b1
2 a: a3
move main branch forward again, rebuilds are one-time
$ hg bookmark -i main -q
$ hg fastannotate --debug -nf a
fastannotate: a: cache broken and deleted
fastannotate: a: 4 new changesets in the main branch
0 a: a1
1 b: a2
3 b: b3
3 b: b4
$ hg fastannotate --debug -nf b
fastannotate: b: cache broken and deleted
fastannotate: b: 4 new changesets in the main branch
1 a: b0
0 b: b1
2 a: a3
$ hg fastannotate --debug -nf a
fastannotate: a: using fast path (resolved fctx: True)
0 a: a1
1 b: a2
3 b: b3
3 b: b4
$ hg fastannotate --debug -nf b
fastannotate: b: using fast path (resolved fctx: True)
1 a: b0
0 b: b1
2 a: a3
list changeset hashes to improve readability
$ hg log -T '{rev}:{node}\n'
4:980e1ab8c516350172928fba95b49ede3b643dca
3:14e123fedad9f491f5dde0beca2a767625a0a93a
2:96495c41e4c12218766f78cdf244e768d7718b0f
1:35c2b781234c994896aba36bd3245d3104e023df
0:653e95416ebb5dbcc25bbc7f75568c9e01f7bd2f
annotate a revision not in the linelog. linelog cannot be used, but does not get rebuilt either
$ hg fastannotate --debug -nf a -r 96495c41e4c12218766f78cdf244e768d7718b0f
fastannotate: a: linelog cannot help in annotating this revision
1 a: b0
0 b: b1
2 a: a3
$ hg fastannotate --debug -nf a -r 2
fastannotate: a: linelog cannot help in annotating this revision
1 a: b0
0 b: b1
2 a: a3
$ hg fastannotate --debug -nf a -r .
fastannotate: a: using fast path (resolved fctx: True)
0 a: a1
1 b: a2
3 b: b3
3 b: b4
annotate an ancient revision where the path matches. linelog can be used
$ hg fastannotate --debug -nf a -r 0
fastannotate: a: using fast path (resolved fctx: True)
0 a: a1
$ hg fastannotate --debug -nf a -r 653e95416ebb5dbcc25bbc7f75568c9e01f7bd2f
fastannotate: a: using fast path (resolved fctx: False)
0 a: a1