Issue #28512: Fixed setting the offset attribute of SyntaxError by

PyErr_SyntaxLocationEx() and PyErr_SyntaxLocationObject().

Lib/test/support/__init__.py

@@ -1041,9 +1041,16 @@ def make_bad_fd():
         file.close()
         unlink(TESTFN)
 
-def check_syntax_error(testcase, statement):
-    testcase.assertRaises(SyntaxError, compile, statement,
-                          '<test string>', 'exec')
+def check_syntax_error(testcase, statement, *, lineno=None, offset=None):
+    with testcase.assertRaises(SyntaxError) as cm:
+        compile(statement, '<test string>', 'exec')
+    err = cm.exception
+    testcase.assertIsNotNone(err.lineno)
+    if lineno is not None:
+        testcase.assertEqual(err.lineno, lineno)
+    testcase.assertIsNotNone(err.offset)
+    if offset is not None:
+        testcase.assertEqual(err.offset, offset)
 
 def open_urlresource(url, *args, **kw):
     import urllib.request, urllib.parse

Lib/test/test_future.py

@@ -2,6 +2,7 @@
 
 import unittest
 from test import support
+import os
 import re
 
 rx = re.compile('\((\S+).py, line (\d+)')
@@ -12,6 +13,12 @@ def get_error_location(msg):
 
 class FutureTest(unittest.TestCase):
 
+    def check_syntax_error(self, err, basename, lineno, offset=0):
+        self.assertIn('%s.py, line %d' % (basename, lineno), str(err))
+        self.assertEqual(os.path.basename(err.filename), basename + '.py')
+        self.assertEqual(err.lineno, lineno)
+        self.assertEqual(err.offset, offset)
+
     def test_future1(self):
         with support.CleanImport('future_test1'):
             from test import future_test1
@@ -27,68 +34,44 @@ class FutureTest(unittest.TestCase):
             from test import test_future3
 
     def test_badfuture3(self):
-        try:
+        with self.assertRaises(SyntaxError) as cm:
             from test import badsyntax_future3
-        except SyntaxError as msg:
-            self.assertEqual(get_error_location(msg), ("badsyntax_future3", '3'))
-        else:
-            self.fail("expected exception didn't occur")
+        self.check_syntax_error(cm.exception, "badsyntax_future3", 3)
 
     def test_badfuture4(self):
-        try:
+        with self.assertRaises(SyntaxError) as cm:
             from test import badsyntax_future4
-        except SyntaxError as msg:
-            self.assertEqual(get_error_location(msg), ("badsyntax_future4", '3'))
-        else:
-            self.fail("expected exception didn't occur")
+        self.check_syntax_error(cm.exception, "badsyntax_future4", 3)
 
     def test_badfuture5(self):
-        try:
+        with self.assertRaises(SyntaxError) as cm:
             from test import badsyntax_future5
-        except SyntaxError as msg:
-            self.assertEqual(get_error_location(msg), ("badsyntax_future5", '4'))
-        else:
-            self.fail("expected exception didn't occur")
+        self.check_syntax_error(cm.exception, "badsyntax_future5", 4)
 
     def test_badfuture6(self):
-        try:
+        with self.assertRaises(SyntaxError) as cm:
             from test import badsyntax_future6
-        except SyntaxError as msg:
-            self.assertEqual(get_error_location(msg), ("badsyntax_future6", '3'))
-        else:
-            self.fail("expected exception didn't occur")
+        self.check_syntax_error(cm.exception, "badsyntax_future6", 3)
 
     def test_badfuture7(self):
-        try:
+        with self.assertRaises(SyntaxError) as cm:
             from test import badsyntax_future7
-        except SyntaxError as msg:
-            self.assertEqual(get_error_location(msg), ("badsyntax_future7", '3'))
-        else:
-            self.fail("expected exception didn't occur")
+        self.check_syntax_error(cm.exception, "badsyntax_future7", 3, 53)
 
     def test_badfuture8(self):
-        try:
+        with self.assertRaises(SyntaxError) as cm:
             from test import badsyntax_future8
-        except SyntaxError as msg:
-            self.assertEqual(get_error_location(msg), ("badsyntax_future8", '3'))
-        else:
-            self.fail("expected exception didn't occur")
+        self.check_syntax_error(cm.exception, "badsyntax_future8", 3)
 
     def test_badfuture9(self):
-        try:
+        with self.assertRaises(SyntaxError) as cm:
             from test import badsyntax_future9
-        except SyntaxError as msg:
-            self.assertEqual(get_error_location(msg), ("badsyntax_future9", '3'))
-        else:
-            self.fail("expected exception didn't occur")
+        self.check_syntax_error(cm.exception, "badsyntax_future9", 3, 0)
 
     def test_badfuture10(self):
-        try:
+        with self.assertRaises(SyntaxError) as cm:
             from test import badsyntax_future10
-        except SyntaxError as msg:
-            self.assertEqual(get_error_location(msg), ("badsyntax_future10", '3'))
-        else:
-            self.fail("expected exception didn't occur")
+        self.check_syntax_error(cm.exception, "badsyntax_future10", 3, 0)
 
     def test_parserhack(self):
         # test that the parser.c::future_hack function works as expected

Lib/test/test_support.py

@@ -240,8 +240,10 @@ class TestSupport(unittest.TestCase):
         self.assertEqual(cm.exception.errno, errno.EBADF)
 
     def test_check_syntax_error(self):
-        support.check_syntax_error(self, "def class")
+        support.check_syntax_error(self, "def class", lineno=1, offset=9)
         self.assertRaises(AssertionError, support.check_syntax_error, self, "1")
+        #with self.assertRaises(AssertionError):
+            #support.check_syntax_error(self, "x=1")
 
     def test_CleanImport(self):
         import importlib

Lib/test/test_symtable.py

@@ -148,15 +148,17 @@ class SymtableTest(unittest.TestCase):
     def test_filename_correct(self):
         ### Bug tickler: SyntaxError file name correct whether error raised
         ### while parsing or building symbol table.
-        def checkfilename(brokencode):
+        def checkfilename(brokencode, offset):
             try:
                 symtable.symtable(brokencode, "spam", "exec")
             except SyntaxError as e:
                 self.assertEqual(e.filename, "spam")
+                self.assertEqual(e.lineno, 1)
+                self.assertEqual(e.offset, offset)
             else:
                 self.fail("no SyntaxError for %r" % (brokencode,))
-        checkfilename("def f(x): foo)(")  # parse-time
-        checkfilename("def f(x): global x")  # symtable-build-time
+        checkfilename("def f(x): foo)(", 14)  # parse-time
+        checkfilename("def f(x): global x", 10)  # symtable-build-time
         symtable.symtable("pass", b"spam", "exec")
         with self.assertRaises(TypeError):
             symtable.symtable("pass", bytearray(b"spam"), "exec")

Lib/test/test_syntax.py

@@ -540,7 +540,7 @@ from test import support
 class SyntaxTestCase(unittest.TestCase):
 
     def _check_error(self, code, errtext,
-                     filename="<testcase>", mode="exec", subclass=None):
+                     filename="<testcase>", mode="exec", subclass=None, lineno=None, offset=None):
         """Check that compiling code raises SyntaxError with errtext.
 
         errtest is a regular expression that must be present in the
@@ -555,6 +555,11 @@ class SyntaxTestCase(unittest.TestCase):
             mo = re.search(errtext, str(err))
             if mo is None:
                 self.fail("SyntaxError did not contain '%r'" % (errtext,))
+            self.assertEqual(err.filename, filename)
+            if lineno is not None:
+                self.assertEqual(err.lineno, lineno)
+            if offset is not None:
+                self.assertEqual(err.offset, offset)
         else:
             self.fail("compile() did not raise SyntaxError")
 
@@ -565,7 +570,7 @@ class SyntaxTestCase(unittest.TestCase):
         self._check_error("del f()", "delete")
 
     def test_global_err_then_warn(self):
-        # Bug tickler:  The SyntaxError raised for one global statement
+        # Bug #763201:  The SyntaxError raised for one global statement
         # shouldn't be clobbered by a SyntaxWarning issued for a later one.
         source = """if 1:
             def error(a):
@@ -575,7 +580,7 @@ class SyntaxTestCase(unittest.TestCase):
                 global b  # SyntaxWarning
             """
         warnings.filterwarnings(action='ignore', category=SyntaxWarning)
-        self._check_error(source, "global")
+        self._check_error(source, "global", lineno=3, offset=16)
         warnings.filters.pop(0)
 
     def test_break_outside_loop(self):

Misc/NEWS

@@ -10,6 +10,9 @@ Release date: TBA
 Core and Builtins
 -----------------
 
+- Issue #28512: Fixed setting the offset attribute of SyntaxError by
+  PyErr_SyntaxLocationEx() and PyErr_SyntaxLocationObject().
+
 - Issue #5322: Fixed setting __new__ to a PyCFunction inside Python code.
   Original patch by Andreas Stührk.
 

Python/errors.c

@@ -1009,16 +1009,15 @@ PyErr_SyntaxLocationObject(PyObject *filename, int lineno, int col_offset)
             PyErr_Clear();
         Py_DECREF(tmp);
     }
+    tmp = NULL;
     if (col_offset >= 0) {
         tmp = PyLong_FromLong(col_offset);
         if (tmp == NULL)
             PyErr_Clear();
-        else {
-            if (_PyObject_SetAttrId(v, &PyId_offset, tmp))
-                PyErr_Clear();
-            Py_DECREF(tmp);
-        }
     }
+    if (_PyObject_SetAttrId(v, &PyId_offset, tmp ? tmp : Py_None))
+        PyErr_Clear();
+    Py_XDECREF(tmp);
     if (filename != NULL) {
         if (_PyObject_SetAttrId(v, &PyId_filename, filename))
             PyErr_Clear();
@@ -1030,9 +1029,6 @@ PyErr_SyntaxLocationObject(PyObject *filename, int lineno, int col_offset)
             Py_DECREF(tmp);
         }
     }
-    if (_PyObject_SetAttrId(v, &PyId_offset, Py_None)) {
-        PyErr_Clear();
-    }
     if (exc != PyExc_SyntaxError) {
         if (!_PyObject_HasAttrId(v, &PyId_msg)) {
             tmp = PyObject_Str(v);