$ cat >> $HGRCPATH <<EOF

  > [extensions]

  > graphlog=

  > rebase=

  > 

  > [alias]

  > tglog = log -G --template "{rev}: '{desc}' {branches}\n"

  > EOF

Create repo a:

  $ hg init a

  $ cd a

  $ echo A > A

  $ hg ci -Am A

  adding A

  $ echo B > B

  $ hg ci -Am B

  adding B

  $ echo C > C

  $ hg ci -Am C

  adding C

  $ echo D > D

  $ hg ci -Am D

  adding D

  $ hg up -q -C 0

  $ echo E > E

  $ hg ci -Am E

  adding E

  created new head

  $ hg up -q -C 0

  $ echo F > F

  $ hg ci -Am F

  adding F

  created new head

  $ hg merge -r 4

  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  (branch merge, don't forget to commit)

  $ hg ci -m G

  $ hg up -q -C 5

  $ echo H > H

  $ hg ci -Am H

  adding H

  created new head

  $ hg tglog

  @  7: 'H'

  |

  | o  6: 'G'

  |/|

  o |  5: 'F'

  | |

  | o  4: 'E'

  |/

  | o  3: 'D'

  | |

  | o  2: 'C'

  | |

  | o  1: 'B'

  |/

  o  0: 'A'

  $ cd ..

Rebasing B onto H:

  $ hg clone -q -u 3 a a1

  $ cd a1

  $ hg rebase --collapse --keepbranches

  $ hg tglog

  @  5: 'Collapsed revision

  |  * B

  |  * C

  |  * D'

  o  4: 'H'

  |

  | o  3: 'G'

  |/|

  o |  2: 'F'

  | |

  | o  1: 'E'

  |/

  o  0: 'A'

  $ hg manifest

  A

  B

  C

  D

  F

  H

  $ cd ..

Rebasing G onto H:

  $ hg clone -q -u . a a2

  $ cd a2

  $ hg rebase --base 6 --collapse

  $ hg tglog

  @  6: 'Collapsed revision

  |  * E

  |  * G'

  o  5: 'H'

  |

  o  4: 'F'

  |

  | o  3: 'D'

  | |

  | o  2: 'C'

  | |

  | o  1: 'B'

  |/

  o  0: 'A'

  $ hg manifest

  A

  E

  F

  H

  $ cd ..

Create repo b:

  $ hg init b

  $ cd b

  $ echo A > A

  $ hg ci -Am A

  adding A

  $ echo B > B

  $ hg ci -Am B

  adding B

  $ hg up -q 0

  $ echo C > C

  $ hg ci -Am C

  adding C

  created new head

  $ hg merge

  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  (branch merge, don't forget to commit)

  $ echo D > D

  $ hg ci -Am D

  adding D

  $ hg up -q 1

  $ echo E > E

  $ hg ci -Am E

  adding E

  created new head

  $ echo F > F

  $ hg ci -Am F

  adding F

  $ hg merge

  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

  (branch merge, don't forget to commit)

  $ hg ci -m G

  $ hg up -q 0

  $ echo H > H

  $ hg ci -Am H

  adding H

  created new head

  $ hg tglog

  @  7: 'H'

  |

  | o    6: 'G'

  | |\

  | | o  5: 'F'

  | | |

  | | o  4: 'E'

  | | |

  | o |  3: 'D'

  | |\|

  | o |  2: 'C'

  |/ /

  | o  1: 'B'

  |/

  o  0: 'A'

  $ cd ..

Rebase and collapse - more than one external (fail):

  $ hg clone -q -u . b b1

  $ cd b1

  $ hg rebase -s 2 --collapse

  abort: unable to collapse, there is more than one external parent

  [255]

Rebase and collapse - E onto H:

  $ hg rebase -s 4 --collapse

  $ hg tglog

  @    5: 'Collapsed revision

  |\   * E

  | |  * F

  | |  * G'

  | o  4: 'H'

  | |

  o |    3: 'D'

  |\ \

  | o |  2: 'C'

  | |/

  o /  1: 'B'

  |/

  o  0: 'A'

  $ hg manifest

  A

  B

  C

  D

  E

  F

  H

  $ cd ..

Create repo c:

  $ hg init c

  $ cd c

  $ echo A > A

  $ hg ci -Am A

  adding A

  $ echo B > B

  $ hg ci -Am B

  adding B

  $ hg up -q 0

  $ echo C > C

  $ hg ci -Am C

  adding C

  created new head

  $ hg merge

  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  (branch merge, don't forget to commit)

  $ echo D > D

  $ hg ci -Am D

  adding D

  $ hg up -q 1

  $ echo E > E

  $ hg ci -Am E

  adding E

  created new head

  $ echo F > E

  $ hg ci -m 'F'

  $ echo G > G

  $ hg ci -Am G

  adding G

  $ hg merge

  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

  (branch merge, don't forget to commit)

  $ hg ci -m H

  $ hg up -q 0

  $ echo I > I

  $ hg ci -Am I

  adding I

  created new head

  $ hg tglog

  @  8: 'I'

  |

  | o    7: 'H'

  | |\

  | | o  6: 'G'

  | | |

  | | o  5: 'F'

  | | |

  | | o  4: 'E'

  | | |

  | o |  3: 'D'

  | |\|

  | o |  2: 'C'

  |/ /

  | o  1: 'B'

  |/

  o  0: 'A'

  $ cd ..

Rebase and collapse - E onto I:

  $ hg clone -q -u . c c1

  $ cd c1

  $ hg rebase -s 4 --collapse

  merging E

  $ hg tglog

  @    5: 'Collapsed revision

  |\   * E

  | |  * F

  | |  * G

  | |  * H'

  | o  4: 'I'

  | |

  o |    3: 'D'

  |\ \

  | o |  2: 'C'

  | |/

  o /  1: 'B'

  |/

  o  0: 'A'

  $ hg manifest

  A

  B

  C

  D

  E

  G

  I

  $ cat E

  F

  $ cd ..

Create repo d:

  $ hg init d

  $ cd d

  $ echo A > A

  $ hg ci -Am A

  adding A

  $ echo B > B

  $ hg ci -Am B

  adding B

  $ echo C > C

  $ hg ci -Am C

  adding C

  $ hg up -q 1

  $ echo D > D

  $ hg ci -Am D

  adding D

  created new head

  $ hg merge

  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  (branch merge, don't forget to commit)

  $ hg ci -m E

  $ hg up -q 0

  $ echo F > F

  $ hg ci -Am F

  adding F

  created new head

  $ hg tglog

  @  5: 'F'

  |

  | o    4: 'E'

  | |\

  | | o  3: 'D'

  | | |

  | o |  2: 'C'

  | |/

  | o  1: 'B'

  |/

  o  0: 'A'

  $ cd ..

Rebase and collapse - B onto F:

  $ hg clone -q -u . d d1

  $ cd d1

  $ hg rebase -s 1 --collapse

  $ hg tglog

  @  2: 'Collapsed revision

  |  * B

  |  * C

  |  * D

  |  * E'

  o  1: 'F'

  |

  o  0: 'A'

  $ hg manifest

  A

  B

  C