bisect: avoid copying ancestor list for non-merge commits
During a bisection, hg needs to compute a list of all ancestors for every
candidate commit. This is accomplished via a bottom-up traversal of the set of
candidates, during which each revision's ancestor list is populated using the
ancestor list of its parent(s). Previously, this involved copying the entire
list, which could be very long in if the bisection range was large.
To help improve this, we can observe that each candidate commit is visited
exactly once, at which point its ancestor list is copied into its children's
lists and then dropped. In the case of non-merge commits, a commit's ancestor
list consists exactly of its parent's list plus itself. This means that we can
trivially reuse the parent's existing list for one of its non-merge children,
which avoids copying entirely if that commit is the parent's only child. This
makes bisections over linear ranges of commits much faster.
During some informal testing in the large publicly-available `mozilla-central`
repository, this noticeably sped up bisections over large ranges of history:
Setup:
$ cd mozilla-central
$ hg bisect --reset
$ hg bisect --good 0
$ hg log -r tip -T '{rev}\n'
628417
Test:
$ time hg bisect --bad tip --noupdate
Before:
real 3m35.927s
user 3m35.553s
sys 0m0.319s
After:
real 1m41.142s
user 1m40.810s
sys 0m0.285s
Test interactions between mq and patch.eol
$ cat <<EOF >> $HGRCPATH
> [extensions]
> mq =
> [diff]
> nodates = 1
> EOF
$ cat > makepatch.py <<EOF
> f = open('eol.diff', 'wb')
> w = f.write
> w(b'test message\n')
> w(b'diff --git a/a b/a\n')
> w(b'--- a/a\n')
> w(b'+++ b/a\n')
> w(b'@@ -1,5 +1,5 @@\n')
> w(b' a\n')
> w(b'-b\r\n')
> w(b'+y\r\n')
> w(b' c\r\n')
> w(b' d\n')
> w(b'-e\n')
> w(b'\\\\ No newline at end of file\n')
> w(b'+z\r\n')
> w(b'\\\\ No newline at end of file\r\n')
> EOF
$ cat > cateol.py <<EOF
> import sys
> try:
> stdout = sys.stdout.buffer
> except AttributeError:
> stdout = sys.stdout
> for line in open(sys.argv[1], 'rb'):
> line = line.replace(b'\r', b'<CR>')
> line = line.replace(b'\n', b'<LF>')
> stdout.write(line + b'\n')
> EOF
$ hg init repo
$ cd repo
$ echo '\.diff' > .hgignore
$ echo '\.rej' >> .hgignore
Test different --eol values
$ "$PYTHON" -c 'open("a", "wb").write(b"a\nb\nc\nd\ne")'
$ hg ci -Am adda
adding .hgignore
adding a
$ "$PYTHON" ../makepatch.py
$ hg qimport eol.diff
adding eol.diff to series file
should fail in strict mode
$ hg qpush
applying eol.diff
patching file a
Hunk #1 FAILED at 0
1 out of 1 hunks FAILED -- saving rejects to file a.rej
patch failed, unable to continue (try -v)
patch failed, rejects left in working directory
errors during apply, please fix and qrefresh eol.diff
[2]
$ hg qpop
popping eol.diff
patch queue now empty
invalid eol
$ hg --config patch.eol='LFCR' qpush
applying eol.diff
patch failed, unable to continue (try -v)
patch failed, rejects left in working directory
errors during apply, please fix and qrefresh eol.diff
[2]
$ hg qpop
popping eol.diff
patch queue now empty
force LF
$ hg --config patch.eol='CRLF' qpush
applying eol.diff
now at: eol.diff
$ hg qrefresh
$ "$PYTHON" ../cateol.py .hg/patches/eol.diff
# HG changeset patch<LF>
# Parent 0d0bf99a8b7a3842c6f8ef09e34f69156c4bd9d0<LF>
test message<LF>
<LF>
diff -r 0d0bf99a8b7a a<LF>
--- a/a<LF>
+++ b/a<LF>
@@ -1,5 +1,5 @@<LF>
-a<LF>
-b<LF>
-c<LF>
-d<LF>
-e<LF>
\ No newline at end of file<LF>
+a<CR><LF>
+y<CR><LF>
+c<CR><LF>
+d<CR><LF>
+z<LF>
\ No newline at end of file<LF>
$ "$PYTHON" ../cateol.py a
a<CR><LF>
y<CR><LF>
c<CR><LF>
d<CR><LF>
z
$ hg qpop
popping eol.diff
patch queue now empty
push again forcing LF and compare revisions
$ hg --config patch.eol='CRLF' qpush
applying eol.diff
now at: eol.diff
$ "$PYTHON" ../cateol.py a
a<CR><LF>
y<CR><LF>
c<CR><LF>
d<CR><LF>
z
$ hg qpop
popping eol.diff
patch queue now empty
push again without LF and compare revisions
$ hg qpush
applying eol.diff
now at: eol.diff
$ "$PYTHON" ../cateol.py a
a<CR><LF>
y<CR><LF>
c<CR><LF>
d<CR><LF>
z
$ hg qpop
popping eol.diff
patch queue now empty
$ cd ..
Test .rej file EOL are left unchanged
$ hg init testeol
$ cd testeol
$ "$PYTHON" -c "open('a', 'wb').write(b'1\r\n2\r\n3\r\n4')"
$ hg ci -Am adda
adding a
$ "$PYTHON" -c "open('a', 'wb').write(b'1\r\n2\r\n33\r\n4')"
$ hg qnew patch1
$ hg qpop
popping patch1
patch queue now empty
$ "$PYTHON" -c "open('a', 'wb').write(b'1\r\n22\r\n33\r\n4')"
$ hg ci -m changea
$ hg --config 'patch.eol=LF' qpush
applying patch1
patching file a
Hunk #1 FAILED at 0
1 out of 1 hunks FAILED -- saving rejects to file a.rej
patch failed, unable to continue (try -v)
patch failed, rejects left in working directory
errors during apply, please fix and qrefresh patch1
[2]
$ hg qpop
popping patch1
patch queue now empty
$ cat a.rej
--- a
+++ a
@@ -1,4 +1,4 @@
1\r (esc)
2\r (esc)
-3\r (esc)
+33\r (esc)
4
\ No newline at end of file
$ hg --config 'patch.eol=auto' qpush
applying patch1
patching file a
Hunk #1 FAILED at 0
1 out of 1 hunks FAILED -- saving rejects to file a.rej
patch failed, unable to continue (try -v)
patch failed, rejects left in working directory
errors during apply, please fix and qrefresh patch1
[2]
$ hg qpop
popping patch1
patch queue now empty
$ cat a.rej
--- a
+++ a
@@ -1,4 +1,4 @@
1\r (esc)
2\r (esc)
-3\r (esc)
+33\r (esc)
4
\ No newline at end of file
$ cd ..