[Python-checkins] r69262 - python/trunk/Lib/importlib/__init__.py

[brett.cannon]

Author: brett.cannon
Date: Tue Feb  3 22:13:05 2009
New Revision: 69262

Log:
Make importlib backwards-compatible to Python 2.2 (but this is not promised to
last; just doing it to be nice).

Also fix a message for an exception.


Modified:
   python/trunk/Lib/importlib/__init__.py

Modified: python/trunk/Lib/importlib/__init__.py
==============================================================================
--- python/trunk/Lib/importlib/__init__.py	(original)
+++ python/trunk/Lib/importlib/__init__.py	Tue Feb  3 22:13:05 2009
@@ -1,4 +1,6 @@
 """Backport of importlib.import_module from 3.x."""
+# While not critical (and in no way guaranteed!), it would be nice to keep this
+# code compatible with Python 2.3.
 import sys
 
 def _resolve_name(name, package, level):
@@ -9,8 +11,14 @@
             raise ValueError("attempted relative import beyond top-level "
                               "package")
     except AttributeError:
-        raise ValueError("__package__ not set to a string")
-    base = package.rsplit('.', level)[0]
+        raise ValueError("'package' not set to a string")
+    try:
+        # rpartition is more "correct" and rfind is just as easy to use, but
+        # neither are in Python 2.3.
+        dot_rindex = package.rindex('.', level)[0]
+        base = package[:dot_rindex]
+    except ValueError:
+        base = package
     if name:
         return "%s.%s" % (base, name)
     else:
@@ -34,5 +42,10 @@
                 break
             level += 1
         name = _resolve_name(name[level:], package, level)
-    __import__(name)
+    # Try to import specifying the level to be as accurate as possible, but
+    # realize that keyword arguments are not found in Python 2.3.
+    try:
+        __import__(name, level=0)
+    except TypeError:
+        __import__(name)
     return sys.modules[name]