merge: do early copy to deal with issue636 Without copies/renames, merges source names are 1:1 with their targets. Copies and renames introduce the possibility that there will be two merges with the same input but different output. By doing the copy to the destination name before the merge, the actual merge becomes 1:1 again, and no source is the input to two different merges. - add a preliminary scan to applyupdates to do copies - for the merge action, pass the old name (for finding ancestors) and the new name (for input to the merge) to filemerge - eliminate the old post-merge copy - lookup file contents from new name in filemerge - pass new name to external merge helper - report merge failure at new name - add a test

quiet:
--- a/foo	Mon Jan 12 13:46:40 1970 +0000
+++ b/foo	Mon Jan 12 13:46:41 1970 +0000
@@ -1,1 +1,1 @@ bar
-bar
+foobar

normal:
diff -r 74de3f1392e2 -r b8b5f023a6ad foo
--- a/foo	Mon Jan 12 13:46:40 1970 +0000
+++ b/foo	Mon Jan 12 13:46:41 1970 +0000
@@ -1,1 +1,1 @@ bar
-bar
+foobar

verbose:
diff -r 74de3f1392e2 -r b8b5f023a6ad foo
--- a/foo	Mon Jan 12 13:46:40 1970 +0000
+++ b/foo	Mon Jan 12 13:46:41 1970 +0000
@@ -1,1 +1,1 @@ bar
-bar
+foobar

debug:
diff -r 74de3f1392e2d67856fb155963441f2610494e1a -r b8b5f023a6ad77fc378bd95cf3fa00cd1414d107 foo
--- a/foo	Mon Jan 12 13:46:40 1970 +0000
+++ b/foo	Mon Jan 12 13:46:41 1970 +0000
@@ -1,1 +1,1 @@ bar
-bar
+foobar