Index: Python/import.c
===================================================================
--- Python/import.c	(revision 45732)
+++ Python/import.c	(working copy)
@@ -1270,11 +1270,18 @@
 		   and there's an __init__ module in that directory */
 #ifdef HAVE_STAT
 		if (stat(buf, &statbuf) == 0 &&         /* it exists */
-		    S_ISDIR(statbuf.st_mode) &&         /* it's a directory */
-		    find_init_module(buf) &&            /* it has __init__.py */
-		    case_ok(buf, len, namelen, name)) { /* and case matches */
-			Py_XDECREF(copy);
-			return &fd_package;
+		    S_ISDIR(statbuf.st_mode)) {         /* it's a directory */
+			if (find_init_module(buf) &&    /* it has __init__.py */
+			    case_ok(buf, len, namelen, name)) { /* and case matches */
+				Py_XDECREF(copy);
+				return &fd_package;
+			}
+			else {
+				char warnstr[500];
+				sprintf(warnstr, "Not importing directory "
+					"'%.450s': missing __init__.py", buf);
+				PyErr_Warn(PyExc_ImportWarning, warnstr);
+			}
 		}
 #else
 		/* XXX How are you going to test for directories? */
Index: Python/exceptions.c
===================================================================
--- Python/exceptions.c	(revision 45732)
+++ Python/exceptions.c	(working copy)
@@ -1647,6 +1647,8 @@
 "Base class for warnings about constructs that will change semantically "
 "in the future.");
 
+PyDoc_STRVAR(ImportWarning__doc__,
+"Base class for warnings about probable mistakes in module imports");
 
 
 /* module global functions */
@@ -1719,6 +1721,7 @@
 PyObject *PyExc_OverflowWarning;
 PyObject *PyExc_RuntimeWarning;
 PyObject *PyExc_FutureWarning;
+PyObject *PyExc_ImportWarning;
 
 
 
@@ -1818,6 +1821,8 @@
   RuntimeWarning__doc__},
  {"FutureWarning", &PyExc_FutureWarning, &PyExc_Warning,
   FutureWarning__doc__},
+ {"ImportWarning", &PyExc_ImportWarning, &PyExc_Warning,
+  ImportWarning__doc__},
  /* Sentinel */
  {NULL}
 };
Index: Include/pyerrors.h
===================================================================
--- Include/pyerrors.h	(revision 45732)
+++ Include/pyerrors.h	(working copy)
@@ -108,6 +108,7 @@
 PyAPI_DATA(PyObject *) PyExc_OverflowWarning;
 PyAPI_DATA(PyObject *) PyExc_RuntimeWarning;
 PyAPI_DATA(PyObject *) PyExc_FutureWarning;
+PyAPI_DATA(PyObject *) PyExc_ImportWarning;
 
 
 /* Convenience functions */