Cmd.complete: use completedefault also with cmd=None

blueyed · blueyed · commit 704a33d2cf91 · 2019-03-09T16:12:25.000+01:00
Otherwise it will trigger a TypeError ("must be str, not NoneType") below with:

    compfunc = getattr(self, 'complete_' + cmd)

The doc for `parseline` states:

&gt; 'command' and 'args' may be None if the line couldn't be parsed.
diff --git a/Lib/cmd.py b/Lib/cmd.py
@@ -263,7 +263,7 @@ def complete(self, text, state):
             endidx = readline.get_endidx() - stripped
             if begidx>0:
                 cmd, args, foo = self.parseline(line)
-                if cmd == '':
+                if not cmd:
                     compfunc = self.completedefault
                 else:
                     try:
diff --git a/Lib/test/test_cmd.py b/Lib/test/test_cmd.py
@@ -9,6 +9,13 @@
 import unittest
 import io
 from test import support
+from unittest.mock import patch
+
+try:
+    import readline
+except ImportError:
+    readline = None
+
 
 class samplecmdclass(cmd.Cmd):
     """
@@ -218,6 +225,22 @@ def test_input_reset_at_EOF(self):
              "(Cmd) \n"
              "(Cmd) *** Unknown syntax: EOF\n"))
 
+    @unittest.skipIf(readline is None, 'No readline module')
+    @patch('readline.get_line_buffer', return_value='foo')
+    @patch('readline.get_begidx', return_value=2)
+    @patch('readline.get_endidx', return_value=2)
+    def test_complete_with_None_from_parseline(self, *args):
+
+        class CustomCmd(cmd.Cmd):
+            def parseline(self, line):
+                return None, None, line
+
+            def completedefault(self, *args):
+                return ['via_completedefault']
+
+        c = CustomCmd()
+        self.assertEqual(c.complete("", 0), "via_completedefault")
+
 
 def test_main(verbose=None):
     from test import test_cmd
diff --git a/Misc/NEWS.d/next/Library/2019-01-11-12-20-48.bpo-35270.Vtm5iW.rst b/Misc/NEWS.d/next/Library/2019-01-11-12-20-48.bpo-35270.Vtm5iW.rst
@@ -0,0 +1 @@
+Cmd.complete: use ``completedefault`` also with ``cmd=None`` returned from ``parseline``.

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	+Cmd.complete: use ``completedefault`` also with ``cmd=None`` returned from ``parseline``.