[3.11] gh-64490: Fix bugs in argument clinic varargs processing (GH-32092)

Lib/test/clinic.test

@@ -3368,7 +3368,6 @@ test_vararg(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
     static const char * const _keywords[] = {"a", NULL};
     static _PyArg_Parser _parser = {NULL, _keywords, "test_vararg", 0};
     PyObject *argsbuf[2];
-    Py_ssize_t noptargs = 0 + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *a;
     PyObject *__clinic_args = NULL;
 
@@ -3387,7 +3386,7 @@ exit:
 
 static PyObject *
 test_vararg_impl(PyObject *module, PyObject *a, PyObject *args)
-/*[clinic end generated code: output=a2baf8c1fade41d2 input=81d33815ad1bae6e]*/
+/*[clinic end generated code: output=ce9334333757f6ea input=81d33815ad1bae6e]*/
 
 /*[clinic input]
 test_vararg_with_default
@@ -3418,7 +3417,7 @@ test_vararg_with_default(PyObject *module, PyObject *const *args, Py_ssize_t nar
     static const char * const _keywords[] = {"a", "b", NULL};
     static _PyArg_Parser _parser = {NULL, _keywords, "test_vararg_with_default", 0};
     PyObject *argsbuf[3];
-    Py_ssize_t noptargs = 0 + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
+    Py_ssize_t noptargs = Py_MIN(nargs, 1) + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *a;
     PyObject *__clinic_args = NULL;
     int b = 0;
@@ -3447,7 +3446,7 @@ exit:
 static PyObject *
 test_vararg_with_default_impl(PyObject *module, PyObject *a, PyObject *args,
                               int b)
-/*[clinic end generated code: output=3821d282c29f8616 input=6e110b54acd9b22d]*/
+/*[clinic end generated code: output=32fb19dd6bcf9185 input=6e110b54acd9b22d]*/
 
 /*[clinic input]
 test_vararg_with_only_defaults

Lib/test/test_clinic.py

@@ -730,6 +730,15 @@ def test_parameters_not_permitted_after_slash_for_now(self):
     x: int
 """)
 
+    def test_parameters_no_more_than_one_vararg(self):
+        s = self.parse_function_should_fail("""
+module foo
+foo.bar
+   *vararg1: object
+   *vararg2: object
+""")
+        self.assertEqual(s, "Error on line 0:\nToo many var args\n")
+
     def test_function_not_at_column_0(self):
         function = self.parse_function("""
   module foo
@@ -1222,13 +1231,47 @@ def test_keyword_only_parameter(self):
             ac_tester.keyword_only_parameter(1)
         self.assertEqual(ac_tester.keyword_only_parameter(a=1), (1,))
 
+    def test_posonly_vararg(self):
+        with self.assertRaises(TypeError):
+            ac_tester.posonly_vararg()
+        self.assertEqual(ac_tester.posonly_vararg(1, 2), (1, 2, ()))
+        self.assertEqual(ac_tester.posonly_vararg(1, b=2), (1, 2, ()))
+        self.assertEqual(ac_tester.posonly_vararg(1, 2, 3, 4), (1, 2, (3, 4)))
+
     def test_vararg_and_posonly(self):
         with self.assertRaises(TypeError):
             ac_tester.vararg_and_posonly()
         with self.assertRaises(TypeError):
             ac_tester.vararg_and_posonly(1, b=2)
         self.assertEqual(ac_tester.vararg_and_posonly(1, 2, 3, 4), (1, (2, 3, 4)))
 
+    def test_vararg(self):
+        with self.assertRaises(TypeError):
+            ac_tester.vararg()
+        with self.assertRaises(TypeError):
+            ac_tester.vararg(1, b=2)
+        self.assertEqual(ac_tester.vararg(1, 2, 3, 4), (1, (2, 3, 4)))
+
+    def test_vararg_with_default(self):
+        with self.assertRaises(TypeError):
+            ac_tester.vararg_with_default()
+        self.assertEqual(ac_tester.vararg_with_default(1, b=False), (1, (), False))
+        self.assertEqual(ac_tester.vararg_with_default(1, 2, 3, 4), (1, (2, 3, 4), False))
+        self.assertEqual(ac_tester.vararg_with_default(1, 2, 3, 4, b=True), (1, (2, 3, 4), True))
+
+    def test_vararg_with_only_defaults(self):
+        self.assertEqual(ac_tester.vararg_with_only_defaults(), ((), None))
+        self.assertEqual(ac_tester.vararg_with_only_defaults(b=2), ((), 2))
+        self.assertEqual(ac_tester.vararg_with_only_defaults(1, b=2), ((1, ), 2))
+        self.assertEqual(ac_tester.vararg_with_only_defaults(1, 2, 3, 4), ((1, 2, 3, 4), None))
+        self.assertEqual(ac_tester.vararg_with_only_defaults(1, 2, 3, 4, b=5), ((1, 2, 3, 4), 5))
+
+    def test_gh_32092_oob(self):
+        ac_tester.gh_32092_oob(1, 2, 3, 4, kw1=5, kw2=6)
+
+    def test_gh_32092_kw_pass(self):
+        ac_tester.gh_32092_kw_pass(1, 2, 3)
+
     def test_gh_99233_refcount(self):
         arg = '*A unique string is not referenced by anywhere else.*'
         arg_refcount_origin = sys.getrefcount(arg)
@@ -1241,5 +1284,6 @@ def test_gh_99240_double_free(self):
         with self.assertRaisesRegex(TypeError, expected_error):
             ac_tester.gh_99240_double_free('a', '\0b')
 
+
 if __name__ == "__main__":
     unittest.main()

Misc/NEWS.d/next/Tools-Demos/2022-08-11-09-58-15.gh-issue-64490.PjwhM4.rst

@@ -0,0 +1,7 @@
+Argument Clinic varargs bugfixes
+
+* Fix out-of-bounds error in :c:func:`!_PyArg_UnpackKeywordsWithVararg`.
+* Fix incorrect check which allowed more than one varargs in clinic.py.
+* Fix miscalculation of ``noptargs`` in generated code.
+* Do not generate ``noptargs`` when there is a vararg argument and no optional argument.
+

Modules/_testclinic.c

@@ -950,6 +950,25 @@ keyword_only_parameter_impl(PyObject *module, PyObject *a)
 }
 
 
+/*[clinic input]
+posonly_vararg
+
+    a: object
+    /
+    b: object
+    *args: object
+
+[clinic start generated code]*/
+
+static PyObject *
+posonly_vararg_impl(PyObject *module, PyObject *a, PyObject *b,
+                    PyObject *args)
+/*[clinic end generated code: output=ee6713acda6b954e input=783427fe7ec2b67a]*/
+{
+    return pack_arguments_newref(3, a, b, args);
+}
+
+
 /*[clinic input]
 vararg_and_posonly
 
@@ -967,6 +986,100 @@ vararg_and_posonly_impl(PyObject *module, PyObject *a, PyObject *args)
 }
 
 
+/*[clinic input]
+vararg
+
+    a: object
+    *args: object
+
+[clinic start generated code]*/
+
+static PyObject *
+vararg_impl(PyObject *module, PyObject *a, PyObject *args)
+/*[clinic end generated code: output=91ab7a0efc52dd5e input=02c0f772d05f591e]*/
+{
+    return pack_arguments_newref(2, a, args);
+}
+
+
+/*[clinic input]
+vararg_with_default
+
+    a: object
+    *args: object
+    b: bool = False
+
+[clinic start generated code]*/
+
+static PyObject *
+vararg_with_default_impl(PyObject *module, PyObject *a, PyObject *args,
+                         int b)
+/*[clinic end generated code: output=182c01035958ce92 input=68cafa6a79f89e36]*/
+{
+    PyObject *obj_b = b ? Py_True : Py_False;
+    return pack_arguments_newref(3, a, args, obj_b);
+}
+
+
+/*[clinic input]
+vararg_with_only_defaults
+
+    *args: object
+    b: object = None
+
+[clinic start generated code]*/
+
+static PyObject *
+vararg_with_only_defaults_impl(PyObject *module, PyObject *args, PyObject *b)
+/*[clinic end generated code: output=c06b1826d91f2f7b input=678c069bc67550e1]*/
+{
+    return pack_arguments_newref(2, args, b);
+}
+
+
+
+/*[clinic input]
+gh_32092_oob
+
+    pos1: object
+    pos2: object
+    *varargs: object
+    kw1: object = None
+    kw2: object = None
+
+Proof-of-concept of GH-32092 OOB bug.
+
+[clinic start generated code]*/
+
+static PyObject *
+gh_32092_oob_impl(PyObject *module, PyObject *pos1, PyObject *pos2,
+                  PyObject *varargs, PyObject *kw1, PyObject *kw2)
+/*[clinic end generated code: output=ee259c130054653f input=46d15c881608f8ff]*/
+{
+    Py_RETURN_NONE;
+}
+
+
+/*[clinic input]
+gh_32092_kw_pass
+
+    pos: object
+    *args: object
+    kw: object = None
+
+Proof-of-concept of GH-32092 keyword args passing bug.
+
+[clinic start generated code]*/
+
+static PyObject *
+gh_32092_kw_pass_impl(PyObject *module, PyObject *pos, PyObject *args,
+                      PyObject *kw)
+/*[clinic end generated code: output=4a2bbe4f7c8604e9 input=5c0bd5b9079a0cce]*/
+{
+    Py_RETURN_NONE;
+}
+
+
 /*[clinic input]
 gh_99233_refcount
 
@@ -1046,7 +1159,13 @@ static PyMethodDef tester_methods[] = {
     POSONLY_KEYWORDS_OPT_KWONLY_OPT_METHODDEF
     POSONLY_OPT_KEYWORDS_OPT_KWONLY_OPT_METHODDEF
     KEYWORD_ONLY_PARAMETER_METHODDEF
+    POSONLY_VARARG_METHODDEF
     VARARG_AND_POSONLY_METHODDEF
+    VARARG_METHODDEF
+    VARARG_WITH_DEFAULT_METHODDEF
+    VARARG_WITH_ONLY_DEFAULTS_METHODDEF
+    GH_32092_OOB_METHODDEF
+    GH_32092_KW_PASS_METHODDEF
     GH_99233_REFCOUNT_METHODDEF
     GH_99240_DOUBLE_FREE_METHODDEF
     {NULL, NULL}