Issue #9850: Fixed macpath.join() for empty first component. Patch by

Oleg Oshmyan.

Lib/macpath.py

@@ -42,7 +42,7 @@ def isabs(s):
 def join(s, *p):
     path = s
     for t in p:
-        if (not s) or isabs(t):
+        if (not path) or isabs(t):
             path = t
             continue
         if t[:1] == ':':

Lib/test/test_macpath.py

@@ -29,6 +29,26 @@ class MacPathTestCase(unittest.TestCase):
         self.assertEqual(split(":conky:mountpoint:"),
                           (':conky:mountpoint', ''))
 
+    def test_join(self):
+        join = macpath.join
+        self.assertEqual(join('a', 'b'), ':a:b')
+        self.assertEqual(join(':a', 'b'), ':a:b')
+        self.assertEqual(join(':a:', 'b'), ':a:b')
+        self.assertEqual(join(':a::', 'b'), ':a::b')
+        self.assertEqual(join(':a', '::b'), ':a::b')
+        self.assertEqual(join('a', ':'), ':a:')
+        self.assertEqual(join('a:', ':'), 'a:')
+        self.assertEqual(join('a', ''), ':a:')
+        self.assertEqual(join('a:', ''), 'a:')
+        self.assertEqual(join('', ''), '')
+        self.assertEqual(join('', 'a:b'), 'a:b')
+        self.assertEqual(join('', 'a', 'b'), ':a:b')
+        self.assertEqual(join('a:b', 'c'), 'a:b:c')
+        self.assertEqual(join('a:b', ':c'), 'a:b:c')
+        self.assertEqual(join('a', ':b', ':c'), ':a:b:c')
+        self.assertEqual(join('a', 'b:'), 'b:')
+        self.assertEqual(join('a:', 'b:'), 'b:')
+
     def test_splitext(self):
         splitext = macpath.splitext
         self.assertEqual(splitext(":foo.ext"), (':foo', '.ext'))

Misc/NEWS

@@ -22,6 +22,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #9850: Fixed macpath.join() for empty first component.  Patch by
+  Oleg Oshmyan.
+
 - Issue #20912: Now directories added to ZIP file have correct Unix and MS-DOS
   directory attributes.