tests/test-issue619.t

merge: back out single-parent fast-forward merge

This backs out

 changeset:   13158:9e7e24052745
 user:        Mads Kiilerich <[e-mail]>
 date:        Tue Dec 07 03:29:21 2010 +0100
 summary:     merge: fast-forward merge with descendant

Before named branches, the invariants were:

a) "merges" always have two parents
b) p1 is not linearly related to p2

Adding named branches made (b) problematic, so the above patch was
introduced, which fixed (b) but broke (a).

After discussion, we decided that the invariants should be:

a) "merges" always have two parents
b) p1 is not linearly related to p2 OR p1 and p2 are on different branches

http://mercurial.selenic.com/bts/issue619

  $ hg init
  $ echo a > a
  $ hg ci -Ama
  adding a

  $ echo b > b
  $ hg branch b
  marked working directory as branch b
  $ hg ci -Amb
  adding b

  $ hg co -C 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

Fast-forward:

  $ hg merge b
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -Ammerge

Bogus fast-forward should fail:

  $ hg merge b
  abort: merging with a working directory ancestor has no effect
  [255]