view tests/test-rebase-bookmarks.t @ 47965:f9e6f2bb721d

rhg: Don’t compare ambiguous files one byte at a time

Even though the use of `BufReader` reduces the number of syscalls to read
the file from disk, `.bytes()` yields a separate `Result` for every byte.
Creating those results and dispatching on them is most likely costly.

Instead, this commit opts for simplicity by reading the entire file into memory
and comparing a single pair of byte strings. Note that memory already needs to
contain the entire previous contents of the file, as read from the filelog.
So with an extremely large file this doubles memory use but does not make it
grow by orders of magnitude.

At first I wrote code that still avoids reading the entire file into memory
and compares one buffer at a time with `BufReader`. Find this code below for
posterity. However its correctness is subtle. I ended up preferring the
simplicity of the obviously-correct single comparison.

```rust
let mut reader = BufReader::new(fobj);
let mut expected = &contents_in_p1[..];
loop {
    let buf = reader.fill_buf().when_reading_file(&fs_path)?;
    if buf.is_empty() {
        // Found EOF
        return Ok(expected.is_empty());
    } else if let Some(rest) = expected.drop_prefix(buf) {
        // What we read so far matches the expected content, continue reading
        let buf_len = buf.len();
        reader.consume(buf_len);
        expected = rest
    } else {
        // Found different content
        return Ok(false);
    }
}
```

Differential Revision: https://phab.mercurial-scm.org/D11412

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > rebase=
  > drawdag=$TESTDIR/drawdag.py
  > 
  > [phases]
  > publish=False
  > 
  > [alias]
  > tglog = log -G --template "{rev}: {node|short} '{desc}' bookmarks: {bookmarks}\n"
  > EOF

Create a repo with several bookmarks
  $ hg init a
  $ cd a

  $ echo a > a
  $ hg ci -Am A
  adding a

  $ echo b > b
  $ hg ci -Am B
  adding b
  $ hg book 'X'
  $ hg book 'Y'

  $ echo c > c
  $ hg ci -Am C
  adding c
  $ hg book 'Z'

  $ hg up -q 0

  $ echo d > d
  $ hg ci -Am D
  adding d
  created new head

  $ hg book W

  $ hg tglog
  @  3: 41acb9dca9eb 'D' bookmarks: W
  |
  | o  2: 49cb3485fa0c 'C' bookmarks: Y Z
  | |
  | o  1: 6c81ed0049f8 'B' bookmarks: X
  |/
  o  0: 1994f17a630e 'A' bookmarks:
  

Move only rebased bookmarks

  $ cd ..
  $ hg clone -q a a1

  $ cd a1
  $ hg up -q Z

Test deleting divergent bookmarks from dest (issue3685)

  $ hg book -r 3 Z@diverge

... and also test that bookmarks not on dest or not being moved aren't deleted

  $ hg book -r 3 X@diverge
  $ hg book -r 0 Y@diverge

  $ hg tglog
  o  3: 41acb9dca9eb 'D' bookmarks: W X@diverge Z@diverge
  |
  | @  2: 49cb3485fa0c 'C' bookmarks: Y Z
  | |
  | o  1: 6c81ed0049f8 'B' bookmarks: X
  |/
  o  0: 1994f17a630e 'A' bookmarks: Y@diverge
  
  $ hg rebase -s Y -d 3
  rebasing 2:49cb3485fa0c Y Z "C"
  saved backup bundle to $TESTTMP/a1/.hg/strip-backup/49cb3485fa0c-126f3e97-rebase.hg

  $ hg tglog
  @  3: 17fb3faba63c 'C' bookmarks: Y Z
  |
  o  2: 41acb9dca9eb 'D' bookmarks: W X@diverge
  |
  | o  1: 6c81ed0049f8 'B' bookmarks: X
  |/
  o  0: 1994f17a630e 'A' bookmarks: Y@diverge
  
Do not try to keep active but deleted divergent bookmark

  $ cd ..
  $ hg clone -q a a4

  $ cd a4
  $ hg up -q 2
  $ hg book W@diverge

  $ hg rebase -s W -d .
  rebasing 3:41acb9dca9eb W tip "D"
  saved backup bundle to $TESTTMP/a4/.hg/strip-backup/41acb9dca9eb-b35a6a63-rebase.hg

  $ hg bookmarks
     W                         3:0d3554f74897
     X                         1:6c81ed0049f8
     Y                         2:49cb3485fa0c
     Z                         2:49cb3485fa0c

Keep bookmarks to the correct rebased changeset

  $ cd ..
  $ hg clone -q a a2

  $ cd a2
  $ hg up -q Z

  $ hg rebase -s 1 -d 3
  rebasing 1:6c81ed0049f8 X "B"
  rebasing 2:49cb3485fa0c Y Z "C"
  saved backup bundle to $TESTTMP/a2/.hg/strip-backup/6c81ed0049f8-a687065f-rebase.hg

  $ hg tglog
  @  3: 3d5fa227f4b5 'C' bookmarks: Y Z
  |
  o  2: e926fccfa8ec 'B' bookmarks: X
  |
  o  1: 41acb9dca9eb 'D' bookmarks: W
  |
  o  0: 1994f17a630e 'A' bookmarks:
  

Keep active bookmark on the correct changeset

  $ cd ..
  $ hg clone -q a a3

  $ cd a3
  $ hg up -q X

  $ hg rebase -d W
  rebasing 1:6c81ed0049f8 X "B"
  rebasing 2:49cb3485fa0c Y Z "C"
  saved backup bundle to $TESTTMP/a3/.hg/strip-backup/6c81ed0049f8-a687065f-rebase.hg

  $ hg tglog
  o  3: 3d5fa227f4b5 'C' bookmarks: Y Z
  |
  @  2: e926fccfa8ec 'B' bookmarks: X
  |
  o  1: 41acb9dca9eb 'D' bookmarks: W
  |
  o  0: 1994f17a630e 'A' bookmarks:
  
  $ hg bookmarks
     W                         1:41acb9dca9eb
   * X                         2:e926fccfa8ec
     Y                         3:3d5fa227f4b5
     Z                         3:3d5fa227f4b5

rebase --continue with bookmarks present (issue3802)

  $ hg up 2
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (leaving bookmark X)
  $ echo 'C' > c
  $ hg add c
  $ hg ci -m 'other C'
  created new head
  $ hg up 3
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg rebase --dest 4
  rebasing 3:3d5fa227f4b5 Y Z "C"
  merging c
  warning: conflicts while merging c! (edit, then use 'hg resolve --mark')
  unresolved conflicts (see 'hg resolve', then 'hg rebase --continue')
  [240]
  $ echo 'c' > c
  $ hg resolve --mark c
  (no more unresolved files)
  continue: hg rebase --continue
  $ hg rebase --continue
  rebasing 3:3d5fa227f4b5 Y Z "C"
  saved backup bundle to $TESTTMP/a3/.hg/strip-backup/3d5fa227f4b5-c6ea2371-rebase.hg
  $ hg tglog
  @  4: 45c0f0ec1203 'C' bookmarks: Y Z
  |
  o  3: b0e10b7175fd 'other C' bookmarks:
  |
  o  2: e926fccfa8ec 'B' bookmarks: X
  |
  o  1: 41acb9dca9eb 'D' bookmarks: W
  |
  o  0: 1994f17a630e 'A' bookmarks:
  

ensure that bookmarks given the names of revset functions can be used
as --rev arguments (issue3950)

  $ hg update -q 3
  $ echo bimble > bimble
  $ hg add bimble
  $ hg commit -q -m 'bisect'
  $ echo e >> bimble
  $ hg ci -m bisect2
  $ echo e >> bimble
  $ hg ci -m bisect3
  $ hg book bisect
  $ hg update -q Y
  $ hg rebase -r '"bisect"^^::"bisect"^' -r bisect -d Z
  rebasing 5:345c90f326a4 "bisect"
  rebasing 6:f677a2907404 "bisect2"
  rebasing 7:325c16001345 bisect tip "bisect3"
  saved backup bundle to $TESTTMP/a3/.hg/strip-backup/345c90f326a4-b4840586-rebase.hg

Bookmark and working parent get moved even if --keep is set (issue5682)

  $ hg init $TESTTMP/book-keep
  $ cd $TESTTMP/book-keep
  $ hg debugdrawdag <<'EOS'
  > B C
  > |/
  > A
  > EOS
  $ eval `hg tags -T 'hg bookmark -ir {node} {tag};\n' | grep -v tip`
  $ rm .hg/localtags
  $ hg up -q B
  $ hg tglog
  o  2: dc0947a82db8 'C' bookmarks: C
  |
  | @  1: 112478962961 'B' bookmarks: B
  |/
  o  0: 426bada5c675 'A' bookmarks: A
  
  $ hg rebase -r B -d C --keep
  rebasing 1:112478962961 B "B"
  $ hg tglog
  @  3: 9769fc65c4c5 'B' bookmarks: B
  |
  o  2: dc0947a82db8 'C' bookmarks: C
  |
  | o  1: 112478962961 'B' bookmarks:
  |/
  o  0: 426bada5c675 'A' bookmarks: A