[Python-checkins] gh-92203: Add closure support to exec(). (#92204)
larryhastings
webhook-mailer at python.org
Fri May 6 13:09:43 EDT 2022
https://github.com/python/cpython/commit/50210643902d28405a57a9672347f43215dbdb3b
commit: 50210643902d28405a57a9672347f43215dbdb3b
branch: main
author: larryhastings <larry at hastings.org>
committer: larryhastings <larry at hastings.org>
date: 2022-05-06T10:09:35-07:00
summary:
gh-92203: Add closure support to exec(). (#92204)
Add a closure keyword-only parameter to exec(). It can only be specified when exec-ing a code object that uses free variables. When specified, it must be a tuple, with exactly the number of cell variables referenced by the code object. closure has a default value of None, and it must be None if the code object doesn't refer to any free variables.
files:
A Misc/NEWS.d/next/Core and Builtins/2022-05-02-17-12-49.gh-issue-92203.-igcjS.rst
M Doc/library/functions.rst
M Lib/test/test_builtin.py
M Python/bltinmodule.c
M Python/clinic/bltinmodule.c.h
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index 47b4b11cced85..83d54da72256a 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -552,7 +552,7 @@ are always available. They are listed here in alphabetical order.
.. index:: builtin: exec
-.. function:: exec(object[, globals[, locals]])
+.. function:: exec(object[, globals[, locals]], *, closure=None)
This function supports dynamic execution of Python code. *object* must be
either a string or a code object. If it is a string, the string is parsed as
@@ -581,6 +581,11 @@ are always available. They are listed here in alphabetical order.
builtins are available to the executed code by inserting your own
``__builtins__`` dictionary into *globals* before passing it to :func:`exec`.
+ The *closure* argument specifies a closure--a tuple of cellvars.
+ It's only valid when the *object* is a code object containing free variables.
+ The length of the tuple must exactly match the number of free variables
+ referenced by the code object.
+
.. audit-event:: exec code_object exec
Raises an :ref:`auditing event <auditing>` ``exec`` with the code object
@@ -599,6 +604,9 @@ are always available. They are listed here in alphabetical order.
Pass an explicit *locals* dictionary if you need to see effects of the
code on *locals* after function :func:`exec` returns.
+ .. versionchanged:: 3.11
+ Added the *closure* parameter.
+
.. function:: filter(function, iterable)
diff --git a/Lib/test/test_builtin.py b/Lib/test/test_builtin.py
index 29039230201ac..ba7a7e20d7dcd 100644
--- a/Lib/test/test_builtin.py
+++ b/Lib/test/test_builtin.py
@@ -24,7 +24,7 @@
from inspect import CO_COROUTINE
from itertools import product
from textwrap import dedent
-from types import AsyncGeneratorType, FunctionType
+from types import AsyncGeneratorType, FunctionType, CellType
from operator import neg
from test import support
from test.support import (swap_attr, maybe_get_event_loop_policy)
@@ -772,6 +772,84 @@ def test_exec_redirected(self):
finally:
sys.stdout = savestdout
+ def test_exec_closure(self):
+ def function_without_closures():
+ return 3 * 5
+
+ result = 0
+ def make_closure_functions():
+ a = 2
+ b = 3
+ c = 5
+ def three_freevars():
+ nonlocal result
+ nonlocal a
+ nonlocal b
+ result = a*b
+ def four_freevars():
+ nonlocal result
+ nonlocal a
+ nonlocal b
+ nonlocal c
+ result = a*b*c
+ return three_freevars, four_freevars
+ three_freevars, four_freevars = make_closure_functions()
+
+ # "smoke" test
+ result = 0
+ exec(three_freevars.__code__,
+ three_freevars.__globals__,
+ closure=three_freevars.__closure__)
+ self.assertEqual(result, 6)
+
+ # should also work with a manually created closure
+ result = 0
+ my_closure = (CellType(35), CellType(72), three_freevars.__closure__[2])
+ exec(three_freevars.__code__,
+ three_freevars.__globals__,
+ closure=my_closure)
+ self.assertEqual(result, 2520)
+
+ # should fail: closure isn't allowed
+ # for functions without free vars
+ self.assertRaises(TypeError,
+ exec,
+ function_without_closures.__code__,
+ function_without_closures.__globals__,
+ closure=my_closure)
+
+ # should fail: closure required but wasn't specified
+ self.assertRaises(TypeError,
+ exec,
+ three_freevars.__code__,
+ three_freevars.__globals__,
+ closure=None)
+
+ # should fail: closure of wrong length
+ self.assertRaises(TypeError,
+ exec,
+ three_freevars.__code__,
+ three_freevars.__globals__,
+ closure=four_freevars.__closure__)
+
+ # should fail: closure using a list instead of a tuple
+ my_closure = list(my_closure)
+ self.assertRaises(TypeError,
+ exec,
+ three_freevars.__code__,
+ three_freevars.__globals__,
+ closure=my_closure)
+
+ # should fail: closure tuple with one non-cell-var
+ my_closure[0] = int
+ my_closure = tuple(my_closure)
+ self.assertRaises(TypeError,
+ exec,
+ three_freevars.__code__,
+ three_freevars.__globals__,
+ closure=my_closure)
+
+
def test_filter(self):
self.assertEqual(list(filter(lambda c: 'a' <= c <= 'z', 'Hello World')), list('elloorld'))
self.assertEqual(list(filter(None, [1, 'hello', [], [3], '', None, 9, 0])), [1, 'hello', [3], 9])
diff --git a/Misc/NEWS.d/next/Core and Builtins/2022-05-02-17-12-49.gh-issue-92203.-igcjS.rst b/Misc/NEWS.d/next/Core and Builtins/2022-05-02-17-12-49.gh-issue-92203.-igcjS.rst
new file mode 100644
index 0000000000000..f765579a1b627
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2022-05-02-17-12-49.gh-issue-92203.-igcjS.rst
@@ -0,0 +1,5 @@
+Add a closure keyword-only parameter to exec(). It can only be specified
+when exec-ing a code object that uses free variables. When specified, it
+must be a tuple, with exactly the number of cell variables referenced by the
+code object. closure has a default value of None, and it must be None if the
+code object doesn't refer to any free variables.
diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c
index 84ebb680e0b8f..072bf75bf8d69 100644
--- a/Python/bltinmodule.c
+++ b/Python/bltinmodule.c
@@ -977,6 +977,8 @@ exec as builtin_exec
globals: object = None
locals: object = None
/
+ *
+ closure: object(c_default="NULL") = None
Execute the given source in the context of globals and locals.
@@ -985,12 +987,14 @@ or a code object as returned by compile().
The globals must be a dictionary and locals can be any mapping,
defaulting to the current globals and locals.
If only globals is given, locals defaults to it.
+The closure must be a tuple of cellvars, and can only be used
+when source is a code object requiring exactly that many cellvars.
[clinic start generated code]*/
static PyObject *
builtin_exec_impl(PyObject *module, PyObject *source, PyObject *globals,
- PyObject *locals)
-/*[clinic end generated code: output=3c90efc6ab68ef5d input=01ca3e1c01692829]*/
+ PyObject *locals, PyObject *closure)
+/*[clinic end generated code: output=7579eb4e7646743d input=f13a7e2b503d1d9a]*/
{
PyObject *v;
@@ -1029,20 +1033,60 @@ builtin_exec_impl(PyObject *module, PyObject *source, PyObject *globals,
return NULL;
}
+ if (closure == Py_None) {
+ closure = NULL;
+ }
+
if (PyCode_Check(source)) {
+ Py_ssize_t num_free = PyCode_GetNumFree((PyCodeObject *)source);
+ if (num_free == 0) {
+ if (closure) {
+ PyErr_SetString(PyExc_TypeError,
+ "cannot use a closure with this code object");
+ return NULL;
+ }
+ } else {
+ int closure_is_ok =
+ closure
+ && PyTuple_CheckExact(closure)
+ && (PyTuple_GET_SIZE(closure) == num_free);
+ if (closure_is_ok) {
+ for (Py_ssize_t i = 0; i < num_free; i++) {
+ PyObject *cell = PyTuple_GET_ITEM(closure, i);
+ if (!PyCell_Check(cell)) {
+ closure_is_ok = 0;
+ break;
+ }
+ }
+ }
+ if (!closure_is_ok) {
+ PyErr_Format(PyExc_TypeError,
+ "code object requires a closure of exactly length %zd",
+ num_free);
+ return NULL;
+ }
+ }
+
if (PySys_Audit("exec", "O", source) < 0) {
return NULL;
}
- if (PyCode_GetNumFree((PyCodeObject *)source) > 0) {
- PyErr_SetString(PyExc_TypeError,
- "code object passed to exec() may not "
- "contain free variables");
- return NULL;
+ if (!closure) {
+ v = PyEval_EvalCode(source, globals, locals);
+ } else {
+ v = PyEval_EvalCodeEx(source, globals, locals,
+ NULL, 0,
+ NULL, 0,
+ NULL, 0,
+ NULL,
+ closure);
}
- v = PyEval_EvalCode(source, globals, locals);
}
else {
+ if (closure != NULL) {
+ PyErr_SetString(PyExc_TypeError,
+ "closure can only be used when source is a code object");
+ }
PyObject *source_copy;
const char *str;
PyCompilerFlags cf = _PyCompilerFlags_INIT;
diff --git a/Python/clinic/bltinmodule.c.h b/Python/clinic/bltinmodule.c.h
index f69b0069ec0f5..48f65091164d0 100644
--- a/Python/clinic/bltinmodule.c.h
+++ b/Python/clinic/bltinmodule.c.h
@@ -408,7 +408,7 @@ builtin_eval(PyObject *module, PyObject *const *args, Py_ssize_t nargs)
}
PyDoc_STRVAR(builtin_exec__doc__,
-"exec($module, source, globals=None, locals=None, /)\n"
+"exec($module, source, globals=None, locals=None, /, *, closure=None)\n"
"--\n"
"\n"
"Execute the given source in the context of globals and locals.\n"
@@ -417,37 +417,52 @@ PyDoc_STRVAR(builtin_exec__doc__,
"or a code object as returned by compile().\n"
"The globals must be a dictionary and locals can be any mapping,\n"
"defaulting to the current globals and locals.\n"
-"If only globals is given, locals defaults to it.");
+"If only globals is given, locals defaults to it.\n"
+"The closure must be a tuple of cellvars, and can only be used\n"
+"when source is a code object requiring exactly that many cellvars.");
#define BUILTIN_EXEC_METHODDEF \
- {"exec", _PyCFunction_CAST(builtin_exec), METH_FASTCALL, builtin_exec__doc__},
+ {"exec", _PyCFunction_CAST(builtin_exec), METH_FASTCALL|METH_KEYWORDS, builtin_exec__doc__},
static PyObject *
builtin_exec_impl(PyObject *module, PyObject *source, PyObject *globals,
- PyObject *locals);
+ PyObject *locals, PyObject *closure);
static PyObject *
-builtin_exec(PyObject *module, PyObject *const *args, Py_ssize_t nargs)
+builtin_exec(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
{
PyObject *return_value = NULL;
+ static const char * const _keywords[] = {"", "", "", "closure", NULL};
+ static _PyArg_Parser _parser = {NULL, _keywords, "exec", 0};
+ PyObject *argsbuf[4];
+ Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
PyObject *source;
PyObject *globals = Py_None;
PyObject *locals = Py_None;
+ PyObject *closure = NULL;
- if (!_PyArg_CheckPositional("exec", 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;
+ goto skip_optional_posonly;
}
+ noptargs--;
globals = args[1];
if (nargs < 3) {
- goto skip_optional;
+ goto skip_optional_posonly;
}
+ noptargs--;
locals = args[2];
-skip_optional:
- return_value = builtin_exec_impl(module, source, globals, locals);
+skip_optional_posonly:
+ if (!noptargs) {
+ goto skip_optional_kwonly;
+ }
+ closure = args[3];
+skip_optional_kwonly:
+ return_value = builtin_exec_impl(module, source, globals, locals, closure);
exit:
return return_value;
@@ -1030,4 +1045,4 @@ builtin_issubclass(PyObject *module, PyObject *const *args, Py_ssize_t nargs)
exit:
return return_value;
}
-/*[clinic end generated code: output=6a2b78ef82bc5155 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=a2c5c53e8aead7c3 input=a9049054013a1b77]*/
More information about the Python-checkins
mailing list