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
#require fuzzywuzzy
$ cat >> $HGRCPATH << EOF
> [extensions]
> releasenotes=
> EOF
Bullet point with a single item spanning a single line
$ hg debugparsereleasenotes - << EOF
> New Features
> ============
>
> * Bullet point item with a single line
> EOF
section: feature
bullet point:
paragraph: Bullet point item with a single line
Bullet point that spans multiple lines.
$ hg debugparsereleasenotes - << EOF
> New Features
> ============
>
> * Bullet point with a paragraph
> that spans multiple lines.
> EOF
section: feature
bullet point:
paragraph: Bullet point with a paragraph that spans multiple lines.
$ hg debugparsereleasenotes - << EOF
> New Features
> ============
>
> * Bullet point with a paragraph
> that spans multiple lines.
>
> And has an empty line between lines too.
> With a line cuddling that.
> EOF
section: feature
bullet point:
paragraph: Bullet point with a paragraph that spans multiple lines.
paragraph: And has an empty line between lines too. With a line cuddling that.
Multiple bullet points. With some entries being multiple lines.
$ hg debugparsereleasenotes - << EOF
> New Features
> ============
>
> * First bullet point. It has a single line.
>
> * Second bullet point.
> It consists of multiple lines.
>
> * Third bullet point. It has a single line.
> EOF
section: feature
bullet point:
paragraph: First bullet point. It has a single line.
bullet point:
paragraph: Second bullet point. It consists of multiple lines.
bullet point:
paragraph: Third bullet point. It has a single line.
Bullet point without newline between items
$ hg debugparsereleasenotes - << EOF
> New Features
> ============
>
> * First bullet point
> * Second bullet point
> And it has multiple lines
> * Third bullet point
> * Fourth bullet point
> EOF
section: feature
bullet point:
paragraph: First bullet point
bullet point:
paragraph: Second bullet point And it has multiple lines
bullet point:
paragraph: Third bullet point
bullet point:
paragraph: Fourth bullet point
Sub-section contents are read
$ hg debugparsereleasenotes - << EOF
> New Features
> ============
>
> First Feature
> -------------
>
> This is the first new feature that was implemented.
>
> And a second paragraph about it.
>
> Second Feature
> --------------
>
> This is the second new feature that was implemented.
>
> Paragraph two.
>
> Paragraph three.
> EOF
section: feature
subsection: First Feature
paragraph: This is the first new feature that was implemented.
paragraph: And a second paragraph about it.
subsection: Second Feature
paragraph: This is the second new feature that was implemented.
paragraph: Paragraph two.
paragraph: Paragraph three.
Multiple sections are read
$ hg debugparsereleasenotes - << EOF
> New Features
> ============
>
> * Feature 1
> * Feature 2
>
> Bug Fixes
> =========
>
> * Fix 1
> * Fix 2
> EOF
section: feature
bullet point:
paragraph: Feature 1
bullet point:
paragraph: Feature 2
section: fix
bullet point:
paragraph: Fix 1
bullet point:
paragraph: Fix 2
Mixed sub-sections and bullet list
$ hg debugparsereleasenotes - << EOF
> New Features
> ============
>
> Feature 1
> ---------
>
> Some words about the first feature.
>
> Feature 2
> ---------
>
> Some words about the second feature.
> That span multiple lines.
>
> Other Changes
> -------------
>
> * Bullet item 1
> * Bullet item 2
> EOF
section: feature
subsection: Feature 1
paragraph: Some words about the first feature.
subsection: Feature 2
paragraph: Some words about the second feature. That span multiple lines.
bullet point:
paragraph: Bullet item 1
bullet point:
paragraph: Bullet item 2
Warn user in case of unexpected block while parsing
$ hg init relnotes-warn
$ cd relnotes-warn
$ touch feature1
$ hg -q commit -A -l - << EOF
> commit 1
>
> .. feature::
>
> new feature added.
> some words about the feature.
> EOF
$ hg releasenote -r .
changeset a4251905c440: unexpected block in release notes directive feature
New Features
============
* new feature added. some words about the feature.
$ cd ..