contrib/editmergeps.ps1

tests: add more tests of copy tracing with removed and re-added files

We had a test where the destination of a copy was removed and then
added back. This patch adds similar cases where the break in history
instead happens to the source file. There are three versions of this:

 1. The break happens before the rename.

 2. The break happens on a branch parallel to the rename (where copy
    tracing is done via the merge base)

 3. The source is added on each side of the merge base. The break in
    history is thus in the form of a deletion when going backwards to
    the merge base and the re-add happens on the other branch.

I've also added calls to `hg graft` in these cases to show the
breakage in issue 6163.

Another factor in these cases is matching nodeid (checked in
copies._tracefile()). I've made two copies each of the cases to show
the impact of that. One of these is the same as a test in
test-rename-merge1.t, so I also deleted that test from there.

Some of these tests currently fail, where "fail" is based on my
current thinking of how things should work. I had initially thought
that we should be more strict about not tracing copies across commits
where the file did not exist, but issue 6163 made me reconsider.

The only test case here that behaved differently in 4.9 is the
exact case reported in issue 6163.

Differential Revision: https://phab.mercurial-scm.org/D6599

# A simple script for opening merge conflicts in editor
# A loose translation of contrib/editmerge to powershell
# Please make sure that both editmergeps.bat and editmerge.ps1 are available
# via %PATH% and use the following Mercurial settings to enable it
#
# [ui]
# editmergeps
# editmergeps.args=$output
# editmergeps.check=changed
# editmergeps.premerge=keep

$file=$args[0]

function Get-Lines
{
  Select-String "^<<<<<<" $file | % {"$($_.LineNumber)"}
}

$ed = $Env:HGEDITOR;
if ($ed -eq $nil)
{
  $ed = $Env:VISUAL;
}
if ($ed -eq $nil)
{
  $ed = $Env:EDITOR;
}
if ($ed -eq $nil)
{
  $ed = $(hg showconfig ui.editor);
}
if ($ed -eq $nil)
{
  Write-Error "merge failed - unable to find editor"
  exit 1
}

if (($ed -eq "vim") -or ($ed -eq "emacs") -or `
    ($ed -eq "nano") -or ($ed -eq "notepad++"))
{
  $lines = Get-Lines
  $firstline = if ($lines.Length -gt 0) { $lines[0] } else { $nil }
  $previousline = $nil;


  # open the editor to the first conflict until there are no more
  # or the user stops editing the file
  while (($firstline -ne $nil) -and ($firstline -ne $previousline))
  {
    if ($ed -eq "notepad++")
    {
        $linearg = "-n$firstline"
    }
    else
    {
        $linearg = "+$firstline"
    }

    Start-Process -Wait -NoNewWindow $ed $linearg,$file
    $previousline = $firstline
    $lines = Get-Lines
    $firstline = if ($lines.Length -gt 0) { $lines[0] } else { $nil }
  }
}
else
{
  & "$ed" $file
}

$conflicts=Get-Lines
if ($conflicts.Length -ne 0)
{
  Write-Output "merge failed - resolve the conflicts (line $conflicts) then use 'hg resolve --mark'"
  exit 1
}

exit 0