commit: respect --no-edit in combination with --amend

Differential Revision: https://phab.mercurial-scm.org/D6464

mercurial/cmdutil.py

@@ -2583,12 +2583,18 b' def amend(ui, repo, old, extra, pats, op'
         message = logmessage(ui, opts)
 
         editform = mergeeditform(old, 'commit.amend')
-        editor = getcommiteditor(editform=editform,
-                                 **pycompat.strkwargs(opts))
 
         if not message:
-            editor = getcommiteditor(edit=True, editform=editform)
             message = old.description()
+            # Default if message isn't provided and --edit is not passed is to
+            # invoke editor, but allow --no-edit. If somehow we don't have any
+            # description, let's always start the editor.
+            doedit = not message or opts.get('edit') in [True, None]
+        else:
+            # Default if message is provided is to not invoke editor, but allow
+            # --edit.
+            doedit = opts.get('edit') is True
+        editor = getcommiteditor(edit=doedit, editform=editform)
 
         pureextra = extra.copy()
         extra['amend_source'] = old.hex()

tests/test-commit-amend.t

@@ -943,17 +943,7 b' Test that amend with --no-edit avoids th'
 (We need a file change here since we won't have a message change)
   $ cp foo foo.orig
   $ echo hi >> foo
-FIXME: This shouldn't start the editor.
   $ HGEDITOR=cat hg commit --amend --no-edit
-  editor should be suppressed
-  
-  
-  HG: Enter commit message.  Lines beginning with 'HG:' are removed.
-  HG: Leave message empty to abort commit.
-  HG: --
-  HG: user: test
-  HG: branch 'silliness'
-  HG: added foo
   $ hg parents --template "{desc}\n"
   editor should be suppressed
   $ hg status -mar