tests/test-merge-internal-tools-pattern.t

contrib: don't hardcode path to bash interpreter

Use the env binary to figure out the correct bash to use.
Certain systems ships with an ancient version of bash, but the
user might have installed a newer one that is earlier in $PATH.

For example the current version of Mac OS X ships version 3.2.51
of bash, which does not understand new fancy builtins such as
readarray. A user might install a newer version of bash, use that
as their shell and add that path before bin.

Make sure that the internal merge tools (internal:fail, internal:local, and
internal:other) are used when matched by a merge-pattern in hgrc

Make sure HGMERGE doesn't interfere with the test:

  $ unset HGMERGE

  $ hg init

Initial file contents:

  $ echo "line 1" > f
  $ echo "line 2" >> f
  $ echo "line 3" >> f
  $ hg ci -Am "revision 0"
  adding f

  $ cat f
  line 1
  line 2
  line 3

Branch 1: editing line 1:

  $ sed 's/line 1/first line/' f > f.new
  $ mv f.new f
  $ hg ci -Am "edited first line"

Branch 2: editing line 3:

  $ hg update 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ sed 's/line 3/third line/' f > f.new
  $ mv f.new f
  $ hg ci -Am "edited third line"
  created new head

Merge using internal:fail tool:

  $ echo "[merge-patterns]" > .hg/hgrc
  $ echo "* = internal:fail" >> .hg/hgrc

  $ hg merge
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]

  $ cat f
  line 1
  line 2
  third line

  $ hg stat
  M f

Merge using internal:local tool:

  $ hg update -C 2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ sed 's/internal:fail/internal:local/' .hg/hgrc > .hg/hgrc.new
  $ mv .hg/hgrc.new .hg/hgrc

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

  $ cat f
  line 1
  line 2
  third line

  $ hg stat
  M f

Merge using internal:other tool:

  $ hg update -C 2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ sed 's/internal:local/internal:other/' .hg/hgrc > .hg/hgrc.new
  $ mv .hg/hgrc.new .hg/hgrc

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

  $ cat f
  first line
  line 2
  line 3

  $ hg stat
  M f

Merge using default tool:

  $ hg update -C 2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm .hg/hgrc

  $ hg merge
  merging f
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ cat f
  first line
  line 2
  third line

  $ hg stat
  M f