tests/test-rebase-pull.t

tags: introduce _readtaghist function

The existing _readtags function has been modified a little and renamed
_readtaghist. A new _readtaghist function has been added, which is a wrappger
around _readtaghist. Its output is the same as the old _readtaghist.

The purpose of this change is to make it possible to automatically merge tag
files. In order to do so we will need to get the line numbers for each of the
tag-node pairs on the first merge parent.

This is not used yet, but will be used on a follow up patch that will introduce
an automatic tag merge algorithm.

I performed some tests to compare the effect of this change. I used timeit to
run the test-tags.t test a 9 times with and without this patch. The results
were:

- without this patch: 3 loops, best of 3: 8.55 sec per loop
- with this patch:    3 loops, best of 3: 8.49 sec per loop

The the test was on average was slightly faster with this patch (although the
difference was probably not statistically significant).

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > rebase=
  > 
  > [alias]
  > tglog = log -G --template "{rev}: '{desc}' {branches}\n"
  > EOF


  $ hg init a
  $ cd a

  $ echo C1 > C1
  $ hg ci -Am C1
  adding C1

  $ echo C2 > C2
  $ hg ci -Am C2
  adding C2

  $ cd ..

  $ hg clone a b
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ hg clone a c
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ cd b

  $ echo L1 > L1
  $ hg ci -Am L1
  adding L1


  $ cd ../a

  $ echo R1 > R1
  $ hg ci -Am R1
  adding R1


  $ cd ../b

Now b has one revision to be pulled from a:

  $ hg pull --rebase
  pulling from $TESTTMP/a (glob)
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)
  saved backup bundle to $TESTTMP/b/.hg/strip-backup/*-backup.hg (glob)

  $ hg tglog
  @  3: 'L1'
  |
  o  2: 'R1'
  |
  o  1: 'C2'
  |
  o  0: 'C1'
  
Re-run:

  $ hg pull --rebase
  pulling from $TESTTMP/a (glob)
  searching for changes
  no changes found


Invoke pull --rebase and nothing to rebase:

  $ cd ../c

  $ hg book norebase
  $ hg pull --rebase
  pulling from $TESTTMP/a (glob)
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  nothing to rebase - working directory parent is already an ancestor of destination 77ae9631bcca
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updating bookmark norebase

  $ hg tglog -l 1
  @  2: 'R1'
  |

pull --rebase --update should ignore --update:

  $ hg pull --rebase --update
  pulling from $TESTTMP/a (glob)
  searching for changes
  no changes found

pull --rebase doesn't update if nothing has been pulled:

  $ hg up -q 1

  $ hg pull --rebase
  pulling from $TESTTMP/a (glob)
  searching for changes
  no changes found

  $ hg tglog -l 1
  o  2: 'R1'
  |

  $ cd ..

pull --rebase works when a specific revision is pulled (issue3619)

  $ cd a
  $ hg tglog
  @  2: 'R1'
  |
  o  1: 'C2'
  |
  o  0: 'C1'
  
  $ echo R2 > R2
  $ hg ci -Am R2
  adding R2
  $ echo R3 > R3
  $ hg ci -Am R3
  adding R3
  $ cd ../c
  $ hg tglog
  o  2: 'R1'
  |
  @  1: 'C2'
  |
  o  0: 'C1'
  
  $ echo L1 > L1
  $ hg ci -Am L1
  adding L1
  created new head
  $ hg pull --rev tip --rebase
  pulling from $TESTTMP/a (glob)
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files
  saved backup bundle to $TESTTMP/c/.hg/strip-backup/ff8d69a621f9-backup.hg (glob)
  $ hg tglog
  @  5: 'L1'
  |
  o  4: 'R3'
  |
  o  3: 'R2'
  |
  o  2: 'R1'
  |
  o  1: 'C2'
  |
  o  0: 'C1'