gh-105879: Add support for keyword arguments to eval and exec (#105885)

Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>

5 files changed, 98 insertions, 33 deletions

diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index be3a64cf41b..4fdf30e0d25 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -524,11 +524,11 @@ are always available.  They are listed here in alphabetical order.
 
 .. _func-eval:
 
-.. function:: eval(expression, globals=None, locals=None)
+.. function:: eval(source, /, globals=None, locals=None)
 
-   :param expression:
+   :param source:
       A Python expression.
-   :type expression: :class:`str` | :ref:`code object <code-objects>`
+   :type source: :class:`str` | :ref:`code object <code-objects>`
 
    :param globals:
       The global namespace (default: ``None``).
@@ -583,11 +583,15 @@ are always available.  They are listed here in alphabetical order.
       Raises an :ref:`auditing event <auditing>` ``exec`` with the code object
       as the argument. Code compilation events may also be raised.
 
+   .. versionchanged:: 3.13
+
+      The *globals* and *locals* arguments can now be passed as keywords.
+
 .. index:: pair: built-in function; exec
 
-.. function:: exec(object, globals=None, locals=None, /, *, closure=None)
+.. function:: exec(source, /, globals=None, locals=None, *, closure=None)
 
-   This function supports dynamic execution of Python code. *object* must be
+   This function supports dynamic execution of Python code. *source* must be
    either a string or a code object.  If it is a string, the string is parsed as
    a suite of Python statements which is then executed (unless a syntax error
    occurs). [#]_ If it is a code object, it is simply executed.  In all cases,
@@ -640,6 +644,10 @@ are always available.  They are listed here in alphabetical order.
    .. versionchanged:: 3.11
       Added the *closure* parameter.
 
+   .. versionchanged:: 3.13
+
+      The *globals* and *locals* arguments can now be passed as keywords.
+
 
 .. function:: filter(function, iterable)
 
diff --git a/Lib/test/test_builtin.py b/Lib/test/test_builtin.py
index 9a0bf524e39..230789f29ff 100644
--- a/Lib/test/test_builtin.py
+++ b/Lib/test/test_builtin.py
@@ -46,6 +46,8 @@ except ImportError:
 x, y = 1e16, 2.9999 # use temporary values to defeat peephole optimizer
 HAVE_DOUBLE_ROUNDING = (x + y == 1e16 + 4)
 
+# used as proof of globals being used
+A_GLOBAL_VALUE = 123
 
 class Squares:
 
@@ -684,6 +686,11 @@ class BuiltinTest(unittest.TestCase):
                 raise ValueError
         self.assertRaises(ValueError, eval, "foo", {}, X())
 
+    def test_eval_kwargs(self):
+        data = {"A_GLOBAL_VALUE": 456}
+        self.assertEqual(eval("globals()['A_GLOBAL_VALUE']", globals=data), 456)
+        self.assertEqual(eval("globals()['A_GLOBAL_VALUE']", locals=data), 123)
+
     def test_general_eval(self):
         # Tests that general mappings can be used for the locals argument
 
@@ -777,6 +784,19 @@ class BuiltinTest(unittest.TestCase):
             del l['__builtins__']
         self.assertEqual((g, l), ({'a': 1}, {'b': 2}))
 
+    def test_exec_kwargs(self):
+        g = {}
+        exec('global z\nz = 1', globals=g)
+        if '__builtins__' in g:
+            del g['__builtins__']
+        self.assertEqual(g, {'z': 1})
+
+        # if we only set locals, the global assignment will not
+        # reach this locals dictionary
+        g = {}
+        exec('global z\nz = 1', locals=g)
+        self.assertEqual(g, {})
+
     def test_exec_globals(self):
         code = compile("print('Hello World!')", "", "exec")
         # no builtin function
diff --git a/Misc/NEWS.d/next/Core and Builtins/2023-06-18-00-27-57.gh-issue-105879.dPw78k.rst b/Misc/NEWS.d/next/Core and Builtins/2023-06-18-00-27-57.gh-issue-105879.dPw78k.rst
new file mode 100644
index 00000000000..e666688d09c
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2023-06-18-00-27-57.gh-issue-105879.dPw78k.rst
@@ -0,0 +1,2 @@
+Allow the *globals* and *locals* arguments to :func:`exec`
+and :func:`eval` to be passed as keywords.
diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c
index 7af3ac9c515..722353ebcbf 100644
--- a/Python/bltinmodule.c
+++ b/Python/bltinmodule.c
@@ -925,9 +925,9 @@ builtin_divmod_impl(PyObject *module, PyObject *x, PyObject *y)
 eval as builtin_eval
 
     source: object
+    /
     globals: object = None
     locals: object = None
-    /
 
 Evaluate the given source in the context of globals and locals.
 
@@ -941,7 +941,7 @@ If only globals is given, locals defaults to it.
 static PyObject *
 builtin_eval_impl(PyObject *module, PyObject *source, PyObject *globals,
                   PyObject *locals)
-/*[clinic end generated code: output=0a0824aa70093116 input=11ee718a8640e527]*/
+/*[clinic end generated code: output=0a0824aa70093116 input=7c7bce5299a89062]*/
 {
     PyObject *result = NULL, *source_copy;
     const char *str;
@@ -1024,9 +1024,9 @@ builtin_eval_impl(PyObject *module, PyObject *source, PyObject *globals,
 exec as builtin_exec
 
     source: object
+    /
     globals: object = None
     locals: object = None
-    /
     *
     closure: object(c_default="NULL") = None
 
@@ -1044,7 +1044,7 @@ when source is a code object requiring exactly that many cellvars.
 static PyObject *
 builtin_exec_impl(PyObject *module, PyObject *source, PyObject *globals,
                   PyObject *locals, PyObject *closure)
-/*[clinic end generated code: output=7579eb4e7646743d input=f13a7e2b503d1d9a]*/
+/*[clinic end generated code: output=7579eb4e7646743d input=25e989b6d87a3a21]*/
 {
     PyObject *v;
 
diff --git a/Python/clinic/bltinmodule.c.h b/Python/clinic/bltinmodule.c.h
index 3f005bcbfb6..f75a8d4ac0c 100644
--- a/Python/clinic/bltinmodule.c.h
+++ b/Python/clinic/bltinmodule.c.h
@@ -395,7 +395,7 @@ exit:
 }
 
 PyDoc_STRVAR(builtin_eval__doc__,
-"eval($module, source, globals=None, locals=None, /)\n"
+"eval($module, source, /, globals=None, locals=None)\n"
 "--\n"
 "\n"
 "Evaluate the given source in the context of globals and locals.\n"
@@ -407,33 +407,63 @@ PyDoc_STRVAR(builtin_eval__doc__,
 "If only globals is given, locals defaults to it.");
 
 #define BUILTIN_EVAL_METHODDEF    \
-    {"eval", _PyCFunction_CAST(builtin_eval), METH_FASTCALL, builtin_eval__doc__},
+    {"eval", _PyCFunction_CAST(builtin_eval), METH_FASTCALL|METH_KEYWORDS, builtin_eval__doc__},
 
 static PyObject *
 builtin_eval_impl(PyObject *module, PyObject *source, PyObject *globals,
                   PyObject *locals);
 
 static PyObject *
-builtin_eval(PyObject *module, PyObject *const *args, Py_ssize_t nargs)
+builtin_eval(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
 {
     PyObject *return_value = NULL;
+    #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
+
+    #define NUM_KEYWORDS 2
+    static struct {
+        PyGC_Head _this_is_not_used;
+        PyObject_VAR_HEAD
+        PyObject *ob_item[NUM_KEYWORDS];
+    } _kwtuple = {
+        .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
+        .ob_item = { &_Py_ID(globals), &_Py_ID(locals), },
+    };
+    #undef NUM_KEYWORDS
+    #define KWTUPLE (&_kwtuple.ob_base.ob_base)
+
+    #else  // !Py_BUILD_CORE
+    #  define KWTUPLE NULL
+    #endif  // !Py_BUILD_CORE
+
+    static const char * const _keywords[] = {"", "globals", "locals", NULL};
+    static _PyArg_Parser _parser = {
+        .keywords = _keywords,
+        .fname = "eval",
+        .kwtuple = KWTUPLE,
+    };
+    #undef KWTUPLE
+    PyObject *argsbuf[3];
+    Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
     PyObject *source;
     PyObject *globals = Py_None;
     PyObject *locals = Py_None;
 
-    if (!_PyArg_CheckPositional("eval", nargs, 1, 3)) {
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 3, 0, argsbuf);
+    if (!args) {
         goto exit;
     }
     source = args[0];
-    if (nargs < 2) {
-        goto skip_optional;
+    if (!noptargs) {
+        goto skip_optional_pos;
     }
-    globals = args[1];
-    if (nargs < 3) {
-        goto skip_optional;
+    if (args[1]) {
+        globals = args[1];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
     }
     locals = args[2];
-skip_optional:
+skip_optional_pos:
     return_value = builtin_eval_impl(module, source, globals, locals);
 
 exit:
@@ -441,7 +471,7 @@ exit:
 }
 
 PyDoc_STRVAR(builtin_exec__doc__,
-"exec($module, source, globals=None, locals=None, /, *, closure=None)\n"
+"exec($module, source, /, globals=None, locals=None, *, closure=None)\n"
 "--\n"
 "\n"
 "Execute the given source in the context of globals and locals.\n"
@@ -467,14 +497,14 @@ builtin_exec(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
     PyObject *return_value = NULL;
     #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
 
-    #define NUM_KEYWORDS 1
+    #define NUM_KEYWORDS 3
     static struct {
         PyGC_Head _this_is_not_used;
         PyObject_VAR_HEAD
         PyObject *ob_item[NUM_KEYWORDS];
     } _kwtuple = {
         .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
-        .ob_item = { &_Py_ID(closure), },
+        .ob_item = { &_Py_ID(globals), &_Py_ID(locals), &_Py_ID(closure), },
     };
     #undef NUM_KEYWORDS
     #define KWTUPLE (&_kwtuple.ob_base.ob_base)
@@ -483,7 +513,7 @@ builtin_exec(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
     #  define KWTUPLE NULL
     #endif  // !Py_BUILD_CORE
 
-    static const char * const _keywords[] = {"", "", "", "closure", NULL};
+    static const char * const _keywords[] = {"", "globals", "locals", "closure", NULL};
     static _PyArg_Parser _parser = {
         .keywords = _keywords,
         .fname = "exec",
@@ -502,17 +532,22 @@ builtin_exec(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
         goto exit;
     }
     source = args[0];
-    if (nargs < 2) {
-        goto skip_optional_posonly;
+    if (!noptargs) {
+        goto skip_optional_pos;
     }
-    noptargs--;
-    globals = args[1];
-    if (nargs < 3) {
-        goto skip_optional_posonly;
+    if (args[1]) {
+        globals = args[1];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
     }
-    noptargs--;
-    locals = args[2];
-skip_optional_posonly:
+    if (args[2]) {
+        locals = args[2];
+        if (!--noptargs) {
+            goto skip_optional_pos;
+        }
+    }
+skip_optional_pos:
     if (!noptargs) {
         goto skip_optional_kwonly;
     }
@@ -1193,4 +1228,4 @@ builtin_issubclass(PyObject *module, PyObject *const *args, Py_ssize_t nargs)
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=6d15edfc194b2c08 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=435d3f286a863c49 input=a9049054013a1b77]*/