Issue #15778: Coerce ImportError.args to a string when it isn't

brettcannon · brettcannon · commit 07c6e7168919 · 2012-08-24T13:05:09.000-04:00
already one.

Patch by Dave Malcolm.
diff --git a/Lib/test/test_exceptions.py b/Lib/test/test_exceptions.py
@@ -937,6 +937,11 @@ def test_attributes(self):
         self.assertEqual(exc.name, 'somename')
         self.assertEqual(exc.path, 'somepath')
 
+    def test_non_str_argument(self):
+        # Issue #15778
+        arg = b'abc'
+        exc = ImportError(arg)
+        self.assertEqual(str(arg), str(exc))
 
 
 def test_main():
diff --git a/Misc/NEWS b/Misc/NEWS
@@ -10,6 +10,9 @@ What's New in Python 3.3.0 Release Candidate 1?
 Core and Builtins
 -----------------
 
+- Issue #15778: ensure that str(ImportError(msg)) returns a str
+  even when msg isn't a str.
+
 - Issue #2051: Source file permission bits are once again correctly
   copied to the cached bytecode file. (The migration to importlib
   reintroduced this problem because these was no regression test. A test
diff --git a/Objects/exceptions.c b/Objects/exceptions.c
@@ -679,7 +679,7 @@ ImportError_traverse(PyImportErrorObject *self, visitproc visit, void *arg)
 static PyObject *
 ImportError_str(PyImportErrorObject *self)
 {
-    if (self->msg) {
+    if (self->msg && PyUnicode_CheckExact(self->msg)) {
         Py_INCREF(self->msg);
         return self->msg;
     }

Original file line number	Diff line number	Diff line change
`@@ -679,7 +679,7 @@ ImportError_traverse(PyImportErrorObject self, visitproc visit, void arg)`
`679`	`679`	`static PyObject *`
`680`	`680`	`ImportError_str(PyImportErrorObject *self)`
`681`	`681`	`{`
`682`		`- if (self->msg) {`
	`682`	`+ if (self->msg && PyUnicode_CheckExact(self->msg)) {`
`683`	`683`	`Py_INCREF(self->msg);`
`684`	`684`	`return self->msg;`
`685`	`685`	`}`