Bug #1115886: os.path.splitext('.cshrc') gives now ('.cshrc', '').

Doc/lib/libposixpath.tex

@@ -234,7 +234,12 @@ empty string.  On systems which do not use drive specifications,
 Split the pathname \var{path} into a pair \code{(\var{root}, \var{ext})} 
 such that \code{\var{root} + \var{ext} == \var{path}},
 and \var{ext} is empty or begins with a period and contains
-at most one period.
+at most one period. Leading periods on the basename are 
+ignored; \code{\var{splitext}.('.cshrc')} returns 
+\code{('.cshrc', '')}.
+
+\versionchanged[Earlier versions could produce an empty root when
+the only period was the first character]{2.6}
 \end{funcdesc}
 
 \begin{funcdesc}{splitunc}{path}

Lib/genericpath.py

@@ -75,3 +75,32 @@ def commonprefix(m):
         if s1[i] != s2[i]:
             return s1[:i]
     return s1[:n]
+
+# Split a path in root and extension.
+# The extension is everything starting at the last dot in the last
+# pathname component; the root is everything before that.
+# It is always true that root + ext == p.
+
+# Generic implementation of splitext, to be parametrized with
+# the separators
+def _splitext(p, sep, altsep, extsep):
+    """Split the extension from a pathname.  
+
+    Extension is everything from the last dot to the end, ignoring
+    leading dots.  Returns "(root, ext)"; ext may be empty."""
+
+    sepIndex = p.rfind(sep)
+    if altsep:
+        altsepIndex = p.rfind(altsep)
+        sepIndex = max(sepIndex, altsepIndex)
+
+    dotIndex = p.rfind(extsep)
+    if dotIndex > sepIndex:
+        # skip all leading dots
+        filenameIndex = sepIndex + 1
+        while filenameIndex < dotIndex:
+            if p[filenameIndex] != extsep:
+                return p[:dotIndex], p[dotIndex:]
+            filenameIndex += 1
+
+    return p, ''

Lib/macpath.py

@@ -2,6 +2,7 @@
 
 import os
 from stat import *
+import genericpath
 from genericpath import *
 
 __all__ = ["normcase","isabs","join","splitdrive","split","splitext",
@@ -69,17 +70,8 @@ def split(s):
 
 
 def splitext(p):
-    """Split a path into root and extension.
-    The extension is everything starting at the last dot in the last
-    pathname component; the root is everything before that.
-    It is always true that root + ext == p."""
-
-    i = p.rfind('.')
-    if i<=p.rfind(':'):
-        return p, ''
-    else:
-        return p[:i], p[i:]
-
+    return genericpath._splitext(p, sep, altsep, extsep)
+splitext.__doc__ = genericpath._splitext.__doc__
 
 def splitdrive(p):
     """Split a pathname into a drive specification and the rest of the

Lib/ntpath.py

@@ -8,6 +8,7 @@ module as os.path.
 import os
 import stat
 import sys
+import genericpath
 from genericpath import *
 
 __all__ = ["normcase","isabs","join","splitdrive","split","splitext",
@@ -182,16 +183,8 @@ def split(p):
 # It is always true that root + ext == p.
 
 def splitext(p):
-    """Split the extension from a pathname.
-
-    Extension is everything from the last dot to the end.
-    Return (root, ext), either part may be empty."""
-
-    i = p.rfind('.')
-    if i<=max(p.rfind('/'), p.rfind('\\')):
-        return p, ''
-    else:
-        return p[:i], p[i:]
+    return genericpath._splitext(p, sep, altsep, extsep)
+splitext.__doc__ = genericpath._splitext.__doc__
 
 
 # Return the tail (basename) part of a path.

Lib/posixpath.py

@@ -12,6 +12,7 @@ for manipulation of the pathname component of URLs.
 
 import os
 import stat
+import genericpath
 from genericpath import *
 
 __all__ = ["normcase","isabs","join","splitdrive","split","splitext",
@@ -88,14 +89,8 @@ def split(p):
 # It is always true that root + ext == p.
 
 def splitext(p):
-    """Split the extension from a pathname.  Extension is everything from the
-    last dot to the end.  Returns "(root, ext)", either part may be empty."""
-    i = p.rfind('.')
-    if i<=p.rfind('/'):
-        return p, ''
-    else:
-        return p[:i], p[i:]
-
+    return genericpath._splitext(p, sep, altsep, extsep)
+splitext.__doc__ = genericpath._splitext.__doc__
 
 # Split a pathname into a drive specification and the rest of the
 # path.  Useful on DOS/Windows/NT; on Unix, the drive is always empty.

Lib/test/test_macpath.py

@@ -48,7 +48,7 @@ class MacPathTestCase(unittest.TestCase):
         splitext = macpath.splitext
         self.assertEquals(splitext(":foo.ext"), (':foo', '.ext'))
         self.assertEquals(splitext("foo:foo.ext"), ('foo:foo', '.ext'))
-        self.assertEquals(splitext(".ext"), ('', '.ext'))
+        self.assertEquals(splitext(".ext"), ('.ext', ''))
         self.assertEquals(splitext("foo.ext:foo"), ('foo.ext:foo', ''))
         self.assertEquals(splitext(":foo.ext:"), (':foo.ext:', ''))
         self.assertEquals(splitext(""), ('', ''))

Lib/test/test_ntpath.py

@@ -18,13 +18,14 @@ def tester(fn, wantResult):
 
 tester('ntpath.splitext("foo.ext")', ('foo', '.ext'))
 tester('ntpath.splitext("/foo/foo.ext")', ('/foo/foo', '.ext'))
-tester('ntpath.splitext(".ext")', ('', '.ext'))
+tester('ntpath.splitext(".ext")', ('.ext', ''))
 tester('ntpath.splitext("\\foo.ext\\foo")', ('\\foo.ext\\foo', ''))
 tester('ntpath.splitext("foo.ext\\")', ('foo.ext\\', ''))
 tester('ntpath.splitext("")', ('', ''))
 tester('ntpath.splitext("foo.bar.ext")', ('foo.bar', '.ext'))
 tester('ntpath.splitext("xx/foo.bar.ext")', ('xx/foo.bar', '.ext'))
 tester('ntpath.splitext("xx\\foo.bar.ext")', ('xx\\foo.bar', '.ext'))
+tester('ntpath.splitext("c:a/b\\c.d")', ('c:a/b\\c', '.d'))
 
 tester('ntpath.splitdrive("c:\\foo\\bar")',
        ('c:', '\\foo\\bar'))

Lib/test/test_posixpath.py

@@ -43,15 +43,27 @@ class PosixPathTest(unittest.TestCase):
 
         self.assertRaises(TypeError, posixpath.split)
 
-    def test_splitext(self):
-        self.assertEqual(posixpath.splitext("foo.ext"), ("foo", ".ext"))
-        self.assertEqual(posixpath.splitext("/foo/foo.ext"), ("/foo/foo", ".ext"))
-        self.assertEqual(posixpath.splitext(".ext"), ("", ".ext"))
-        self.assertEqual(posixpath.splitext("/foo.ext/foo"), ("/foo.ext/foo", ""))
-        self.assertEqual(posixpath.splitext("foo.ext/"), ("foo.ext/", ""))
-        self.assertEqual(posixpath.splitext(""), ("", ""))
-        self.assertEqual(posixpath.splitext("foo.bar.ext"), ("foo.bar", ".ext"))
+    def splitextTest(self, path, filename, ext):
+        self.assertEqual(posixpath.splitext(path), (filename, ext))
+        self.assertEqual(posixpath.splitext("/" + path), ("/" + filename, ext))
+        self.assertEqual(posixpath.splitext("abc/" + path), ("abc/" + filename, ext))
+        self.assertEqual(posixpath.splitext("abc.def/" + path), ("abc.def/" + filename, ext))
+        self.assertEqual(posixpath.splitext("/abc.def/" + path), ("/abc.def/" + filename, ext))
+        self.assertEqual(posixpath.splitext(path + "/"), (filename + ext + "/", ""))
 
+    def test_splitext(self):
+        self.splitextTest("foo.bar", "foo", ".bar")
+        self.splitextTest("foo.boo.bar", "foo.boo", ".bar")
+        self.splitextTest("foo.boo.biff.bar", "foo.boo.biff", ".bar")
+        self.splitextTest(".csh.rc", ".csh", ".rc")
+        self.splitextTest("nodots", "nodots", "")
+        self.splitextTest(".cshrc", ".cshrc", "")
+        self.splitextTest("...manydots", "...manydots", "")
+        self.splitextTest("...manydots.ext", "...manydots", ".ext")
+        self.splitextTest(".", ".", "")
+        self.splitextTest("..", "..", "")
+        self.splitextTest("........", "........", "")
+        self.splitextTest("", "", "")
         self.assertRaises(TypeError, posixpath.splitext)
 
     def test_isabs(self):

Misc/NEWS

@@ -152,6 +152,8 @@ Core and builtins
 Library
 -------
 
+- Bug #1115886: os.path.splitext('.cshrc') gives now ('.cshrc', '').
+
 - Patch #787789: allow to pass custom TestRunner instances to unittest's
   main() function.