tests/test-merge9.t

tests: invoke printenv.py via sh -c for test portability

On Windows platform, invoking printenv.py directly via hook is
problematic, because:

  - unless binding between *.py suffix and python runtime, application
    selector dialog is displayed, and running test is blocked at each
    printenv.py invocations

  - it isn't safe to assume binding between *.py suffix and python
    runtime, because application binding is easily broken

    For example, installing IDE (VisualStudio with Python Tools, or
    so) often requires binding between source files and IDE itself.

This patch invokes printenv.py via sh -c for test portability. This is
a kind of follow up for d19787db6fe0, which eliminated explicit
"python" for printenv.py. There are already other 'sh -c "printenv.py"'
in *.t files, and this fix should be reasonable.

This changes were confirmed in cases below:

  - without any application binding for *.py suffix
  - with binding between *.py suffix and VisualStudio

This patch also replaces "echo + redirection" style with "heredoc"
style, because:

  - hook command line is parsed by cmd.exe as shell at first, and
  - single quotation can't quote arguments on cmd.exe, therefore,
  - "printenv.py foobar" should be quoted by double quotation, but
  - nested quoting (or tricky escaping) isn't readable

test that we don't interrupt the merge session if
a file-level merge failed

  $ hg init repo
  $ cd repo

  $ echo foo > foo
  $ echo a > bar
  $ hg ci -Am 'add foo'
  adding bar
  adding foo

  $ hg mv foo baz
  $ echo b >> bar
  $ echo quux > quux1
  $ hg ci -Am 'mv foo baz'
  adding quux1

  $ hg up -qC 0
  $ echo >> foo
  $ echo c >> bar
  $ echo quux > quux2
  $ hg ci -Am 'change foo'
  adding quux2
  created new head

test with the rename on the remote side
  $ HGMERGE=false hg merge
  merging bar
  merging foo and baz to baz
  merging bar failed!
  1 files updated, 1 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]
  $ hg resolve -l
  U bar
  R baz

test with the rename on the local side
  $ hg up -C 1
  3 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ HGMERGE=false hg merge
  merging bar
  merging baz and foo to baz
  merging bar failed!
  1 files updated, 1 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]

show unresolved
  $ hg resolve -l
  U bar
  R baz

unmark baz
  $ hg resolve -u baz

show
  $ hg resolve -l
  U bar
  U baz
  $ hg st
  M bar
  M baz
  M quux2
  ? bar.orig

re-resolve baz
  $ hg resolve baz
  merging baz and foo to baz

after resolve
  $ hg resolve -l
  U bar
  R baz

resolve all warning
  $ hg resolve
  abort: no files or directories specified
  (use --all to re-merge all unresolved files)
  [255]

resolve all
  $ hg resolve -a
  merging bar
  warning: conflicts while merging bar! (edit, then use 'hg resolve --mark')
  [1]

after
  $ hg resolve -l
  U bar
  R baz

  $ cd ..