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
$ cat > correct.py <<NO_CHECK_EOF
> def toto(arg1, arg2):
> del arg2
> return (5 + 6, 9)
> NO_CHECK_EOF
$ cat > wrong.py <<NO_CHECK_EOF
> def toto( arg1, arg2):
> del(arg2)
> return ( 5+6, 9)
> def badwrap():
> return 1 + \\
> 2
> NO_CHECK_EOF
$ cat > quote.py <<NO_CHECK_EOF
> # let's use quote in comments
> (''' ( 4x5 )
> but """\\''' and finally''',
> """let's fool checkpatch""", '1+2',
> '"""', 42+1, """and
> ( 4-1 ) """, "( 1+1 )\" and ")
> a, '\\\\\\\\', "\\\\\\" x-2", "c-1"
> NO_CHECK_EOF
$ cat > classstyle.py <<NO_CHECK_EOF
> class newstyle_class(object):
> pass
>
> class oldstyle_class:
> pass
>
> class empty():
> pass
>
> no_class = 1:
> pass
> NO_CHECK_EOF
$ check_code="$TESTDIR"/../contrib/check-code.py
$ "$check_code" ./wrong.py ./correct.py ./quote.py ./classstyle.py
./wrong.py:1:
> def toto( arg1, arg2):
gratuitous whitespace in () or []
./wrong.py:2:
> del(arg2)
Python keyword is not a function
./wrong.py:3:
> return ( 5+6, 9)
gratuitous whitespace in () or []
missing whitespace in expression
./wrong.py:5:
> return 1 + \
Use () to wrap long lines in Python, not \
./quote.py:5:
> '"""', 42+1, """and
missing whitespace in expression
[1]
$ cat > python3-compat.py << NO_CHECK_EOF
> foo <> bar
> reduce(lambda a, b: a + b, [1, 2, 3, 4])
> dict(key=value)
> NO_CHECK_EOF
$ "$check_code" python3-compat.py
python3-compat.py:1:
> foo <> bar
<> operator is not available in Python 3+, use !=
python3-compat.py:2:
> reduce(lambda a, b: a + b, [1, 2, 3, 4])
reduce is not available in Python 3+
python3-compat.py:3:
> dict(key=value)
dict() is different in Py2 and 3 and is slower than {}
[1]
$ cat > foo.c <<NO_CHECK_EOF
> void narf() {
> strcpy(foo, bar);
> // strcpy_s is okay, but this comment is not
> strcpy_s(foo, bar);
> }
> NO_CHECK_EOF
$ "$check_code" ./foo.c
./foo.c:2:
> strcpy(foo, bar);
don't use strcpy, use strlcpy or memcpy
./foo.c:3:
> // strcpy_s is okay, but this comment is not
don't use //-style comments
[1]
$ cat > is-op.py <<NO_CHECK_EOF
> # is-operator comparing number or string literal
> x = None
> y = x is 'foo'
> y = x is "foo"
> y = x is 5346
> y = x is -6
> y = x is not 'foo'
> y = x is not "foo"
> y = x is not 5346
> y = x is not -6
> NO_CHECK_EOF
$ "$check_code" ./is-op.py
./is-op.py:3:
> y = x is 'foo'
object comparison with literal
./is-op.py:4:
> y = x is "foo"
object comparison with literal
./is-op.py:5:
> y = x is 5346
object comparison with literal
./is-op.py:6:
> y = x is -6
object comparison with literal
./is-op.py:7:
> y = x is not 'foo'
object comparison with literal
./is-op.py:8:
> y = x is not "foo"
object comparison with literal
./is-op.py:9:
> y = x is not 5346
object comparison with literal
./is-op.py:10:
> y = x is not -6
object comparison with literal
[1]
$ cat > for-nolineno.py <<NO_CHECK_EOF
> except:
> NO_CHECK_EOF
$ "$check_code" for-nolineno.py --nolineno
for-nolineno.py:0:
> except:
naked except clause
[1]
$ cat > warning.t <<NO_CHECK_EOF
> $ function warnonly {
> > }
> $ diff -N aaa
> $ function onwarn {}
> NO_CHECK_EOF
$ "$check_code" warning.t
$ "$check_code" --warn warning.t
warning.t:1:
> $ function warnonly {
warning: don't use 'function', use old style
warning.t:3:
> $ diff -N aaa
warning: don't use 'diff -N'
warning.t:4:
> $ function onwarn {}
warning: don't use 'function', use old style
[1]
$ cat > error.t <<NO_CHECK_EOF
> $ [ foo == bar ]
> NO_CHECK_EOF
$ "$check_code" error.t
error.t:1:
> $ [ foo == bar ]
[ foo == bar ] is a bashism, use [ foo = bar ] instead
[1]
$ rm error.t
$ cat > raise-format.py <<NO_CHECK_EOF
> raise SomeException, message
> # this next line is okay
> raise SomeException(arg1, arg2)
> NO_CHECK_EOF
$ "$check_code" not-existing.py raise-format.py
Skipping*not-existing.py* (glob)
raise-format.py:1:
> raise SomeException, message
don't use old-style two-argument raise, use Exception(message)
[1]
$ cat <<NO_CHECK_EOF > tab.t
> indent
> > heredoc
> NO_CHECK_EOF
$ "$check_code" tab.t
tab.t:1:
> indent
don't use tabs to indent
[1]
$ rm tab.t
$ cat > rst.py <<NO_CHECK_EOF
> """problematic rst text
>
> .. note::
> wrong
> """
>
> '''
>
> .. note::
>
> valid
>
> new text
>
> .. note::
>
> also valid
> '''
>
> """mixed
>
> .. note::
>
> good
>
> .. note::
> plus bad
> """
> NO_CHECK_EOF
$ $check_code -w rst.py
rst.py:3:
> .. note::
warning: add two newlines after '.. note::'
rst.py:26:
> .. note::
warning: add two newlines after '.. note::'
[1]
$ cat > ./map-inside-gettext.py <<NO_CHECK_EOF
> print(_("map inside gettext %s" % v))
>
> print(_("concatenating " " by " " space %s" % v))
> print(_("concatenating " + " by " + " '+' %s" % v))
>
> print(_("mapping operation in different line %s"
> % v))
>
> print(_(
> "leading spaces inside of '(' %s" % v))
> NO_CHECK_EOF
$ "$check_code" ./map-inside-gettext.py
./map-inside-gettext.py:1:
> print(_("map inside gettext %s" % v))
don't use % inside _()
./map-inside-gettext.py:3:
> print(_("concatenating " " by " " space %s" % v))
don't use % inside _()
./map-inside-gettext.py:4:
> print(_("concatenating " + " by " + " '+' %s" % v))
don't use % inside _()
./map-inside-gettext.py:6:
> print(_("mapping operation in different line %s"
don't use % inside _()
./map-inside-gettext.py:9:
> print(_(
don't use % inside _()
[1]
web templates
$ mkdir -p mercurial/templates
$ cat > mercurial/templates/example.tmpl <<NO_CHECK_EOF
> {desc}
> {desc|escape}
> {desc|firstline}
> {desc|websub}
> NO_CHECK_EOF
$ "$check_code" --warnings mercurial/templates/example.tmpl
mercurial/templates/example.tmpl:2:
> {desc|escape}
warning: follow desc keyword with either firstline or websub
[1]
'string join across lines with no space' detection
$ cat > stringjoin.py <<NO_CHECK_EOF
> foo = (' foo'
> 'bar foo.'
> 'bar foo:'
> 'bar foo@'
> 'bar foo%'
> 'bar foo*'
> 'bar foo+'
> 'bar foo-'
> 'bar')
> NO_CHECK_EOF
'missing _() in ui message' detection
$ cat > uigettext.py <<NO_CHECK_EOF
> ui.status("% 10s %05d % -3.2f %*s %%"
> # this use '\\\\' instead of '\\', because the latter in
> # heredoc on shell becomes just '\'
> '\\\\ \n \t \0'
> """12345
> """
> '''.:*+-=
> ''' "%-6d \n 123456 .:*+-= foobar")
> NO_CHECK_EOF
superfluous pass
$ cat > superfluous_pass.py <<NO_CHECK_EOF
> # correct examples
> if foo:
> pass
> else:
> # comment-only line means still need pass
> pass
> def nothing():
> pass
> class empty(object):
> pass
> if whatever:
> passvalue(value)
> # bad examples
> if foo:
> "foo"
> pass
> else: # trailing comment doesn't fool checker
> wat()
> pass
> def nothing():
> "docstring means no pass"
> pass
> class empty(object):
> """multiline
> docstring also
> means no pass"""
> pass
> NO_CHECK_EOF
(Checking multiple invalid files at once examines whether caching
translation table for repquote() works as expected or not. All files
should break rules depending on result of repquote(), in this case)
$ "$check_code" stringjoin.py uigettext.py superfluous_pass.py
stringjoin.py:1:
> foo = (' foo'
string join across lines with no space
stringjoin.py:2:
> 'bar foo.'
string join across lines with no space
stringjoin.py:3:
> 'bar foo:'
string join across lines with no space
stringjoin.py:4:
> 'bar foo@'
string join across lines with no space
stringjoin.py:5:
> 'bar foo%'
string join across lines with no space
stringjoin.py:6:
> 'bar foo*'
string join across lines with no space
stringjoin.py:7:
> 'bar foo+'
string join across lines with no space
stringjoin.py:8:
> 'bar foo-'
string join across lines with no space
uigettext.py:1:
> ui.status("% 10s %05d % -3.2f %*s %%"
missing _() in ui message (use () to hide false-positives)
superfluous_pass.py:14:
> if foo:
omit superfluous pass
superfluous_pass.py:17:
> else: # trailing comment doesn't fool checker
omit superfluous pass
superfluous_pass.py:20:
> def nothing():
omit superfluous pass
superfluous_pass.py:23:
> class empty(object):
omit superfluous pass
[1]
Check code fragments embedded in test script
$ cat > embedded-code.t <<NO_CHECK_EOF
> code fragment in doctest style
> >>> x = (1,2)
> ...
> ... x = (1,2)
>
> code fragment in heredoc style
> $ python <<EOF
> > x = (1,2)
> > EOF
>
> code fragment in file heredoc style
> $ python > file.py <<EOF
> > x = (1,2)
> > EOF
> NO_CHECK_EOF
$ "$check_code" embedded-code.t
embedded-code.t:2:
> x = (1,2)
missing whitespace after ,
embedded-code.t:4:
> x = (1,2)
missing whitespace after ,
embedded-code.t:8:
> x = (1,2)
missing whitespace after ,
embedded-code.t:13:
> x = (1,2)
missing whitespace after ,
[1]
"max warnings per file" is shared by all embedded code fragments
$ "$check_code" --per-file=3 embedded-code.t
embedded-code.t:2:
> x = (1,2)
missing whitespace after ,
embedded-code.t:4:
> x = (1,2)
missing whitespace after ,
embedded-code.t:8:
> x = (1,2)
missing whitespace after ,
(too many errors, giving up)
[1]