Fix the problem of not raising a TypeError exception when doing:

    '%g' % '1'
    '%d' % '1'

Add a test for these conditions
Fix the test so that if not exception is raise, this is a failure

Lib/test/test_format.py

-from test.test_support import verbose, have_unicode
+from test.test_support import verbose, have_unicode, TestFailed
 import sys
 
 # test string formatting operator (I am not sure if this is being tested
@@ -210,9 +210,15 @@ def test_exc(formatstr, args, exception, excmsg):
         if verbose: print 'no'
         print 'Unexpected exception'
         raise
+    else:
+        raise TestFailed, 'did not get expected exception: %s' % excmsg
 
 test_exc('abc %a', 1, ValueError,
          "unsupported format character 'a' (0x61) at index 5")
 if have_unicode:
     test_exc(unicode('abc %\u3000','raw-unicode-escape'), 1, ValueError,
              "unsupported format character '?' (0x3000) at index 5")
+
+test_exc('%d', '1', TypeError, "int argument required")
+test_exc('%g', '1', TypeError, "float argument required")
+

Objects/stringobject.c

@@ -3120,11 +3120,11 @@ formatfloat(char *buf, size_t buflen, int flags,
 	   worst case length = 3 + 10 (len of INT_MAX) + 1 = 14 (use 20)*/
 	char fmt[20];
 	double x;
-	v = PyNumber_Float(v);
-	if (!v)
+	x = PyFloat_AsDouble(v);
+	if (x == -1.0 && PyErr_Occurred()) {
+		PyErr_SetString(PyExc_TypeError, "float argument required");
 		return -1;
-	x = PyFloat_AS_DOUBLE(v);
-	Py_DECREF(v);
+	}
 	if (prec < 0)
 		prec = 6;
 	if (type == 'f' && fabs(x)/1e25 >= 1e25)
@@ -3299,11 +3299,11 @@ formatint(char *buf, size_t buflen, int flags,
 	char fmt[64];	/* plenty big enough! */
 	long x;
 
-	v = PyNumber_Int(v);
-	if (!v)
+	x = PyInt_AsLong(v);
+	if (x == -1 && PyErr_Occurred()) {
+		PyErr_SetString(PyExc_TypeError, "int argument required");
 		return -1;
-	x = PyInt_AS_LONG(v);
-	Py_DECREF(v);
+	}
 	if (prec < 0)
 		prec = 1;