Mercurial > cpython-lru_cache-weakref

diff Objects/unicodeobject.c @ 23310:01765d30532e 2.2

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
backport tim_one's patch: Repair widespread misuse of _PyString_Resize. Since it's clear people don't understand how this function works, also beefed up the docs. The most common usage error is of this form (often spread out across gotos): if (_PyString_Resize(&s, n) < 0) { Py_DECREF(s); s = NULL; goto outtahere; } The error is that if _PyString_Resize runs out of memory, it automatically decrefs the input string object s (which also deallocates it, since its refcount must be 1 upon entry), and sets s to NULL. So if the "if" branch ever triggers, it's an error to call Py_DECREF(s): s is already NULL! A correct way to write the above is the simpler (and intended) if (_PyString_Resize(&s, n) < 0) goto outtahere; Bugfix candidate. Original patch(es): python/dist/src/Objects/fileobject.c:2.161 python/dist/src/Objects/stringobject.c:2.161 python/dist/src/Objects/unicodeobject.c:2.147
author Anthony Baxter <anthonybaxter@gmail.com>
date Tue, 30 Apr 2002 03:41:53 +0000
parents dd350b639309
children 886686fc92a9
line wrap: on
line diff
--- a/Objects/unicodeobject.c	Tue Apr 30 03:33:15 2002 +0000
+++ b/Objects/unicodeobject.c	Tue Apr 30 03:41:53 2002 +0000
@@ -927,10 +927,7 @@
         *out++ = '-';
     }
 
-    if (_PyString_Resize(&v, out - start)) {
-        Py_DECREF(v);
-        return NULL;
-    }
+    _PyString_Resize(&v, out - start);
     return v;
 }
 
@@ -1778,7 +1775,7 @@
 	    /* Resize the string if necessary */
 	    if (offset + 12 > PyString_GET_SIZE(repr)) {
 		if (_PyString_Resize(&repr, PyString_GET_SIZE(repr) + 100))
-		    goto onError;
+		    return NULL;
 		p = PyString_AS_STRING(repr) + offset;
 	    }
 
@@ -1861,14 +1858,8 @@
         *p++ = PyString_AS_STRING(repr)[1];
 
     *p = '\0';
-    if (_PyString_Resize(&repr, p - PyString_AS_STRING(repr)))
-	goto onError;
-
+    _PyString_Resize(&repr, p - PyString_AS_STRING(repr));
     return repr;
-
- onError:
-    Py_DECREF(repr);
-    return NULL;
 }
 
 PyObject *PyUnicode_EncodeUnicodeEscape(const Py_UNICODE *s,
@@ -1999,14 +1990,8 @@
             *p++ = (char) ch;
     }
     *p = '\0';
-    if (_PyString_Resize(&repr, p - q))
-	goto onError;
-
+    _PyString_Resize(&repr, p - q);
     return repr;
-
- onError:
-    Py_DECREF(repr);
-    return NULL;
 }
 
 PyObject *PyUnicode_AsRawUnicodeEscapeString(PyObject *unicode)
@@ -2106,8 +2091,7 @@
     }
     /* Resize if error handling skipped some characters */
     if (s - start < PyString_GET_SIZE(repr))
-	if (_PyString_Resize(&repr, s - start))
-	    goto onError;
+	_PyString_Resize(&repr, s - start);
     return repr;
 
  onError:
@@ -2254,8 +2238,7 @@
     }
     /* Resize if error handling skipped some characters */
     if (s - start < PyString_GET_SIZE(repr))
-	if (_PyString_Resize(&repr, s - start))
-	    goto onError;
+	_PyString_Resize(&repr, s - start);
     return repr;
 
  onError:
@@ -2602,12 +2585,11 @@
 	Py_DECREF(x);
     }
     if (s - PyString_AS_STRING(v) < PyString_GET_SIZE(v))
-	if (_PyString_Resize(&v, (int)(s - PyString_AS_STRING(v))))
-	    goto onError;
+	_PyString_Resize(&v, (int)(s - PyString_AS_STRING(v)));
     return v;
 
  onError:
-    Py_DECREF(v);
+    Py_XDECREF(v);
     return NULL;
 }