Merge branch '3.12' of https://github.com/python/cpython into 3.12

6 files changed, 38 insertions, 13 deletions

diff --git a/Lib/test/test_fstring.py b/Lib/test/test_fstring.py
index 8f6b576..1eb3bfb 100644
--- a/Lib/test/test_fstring.py
+++ b/Lib/test/test_fstring.py
@@ -13,6 +13,7 @@ import re
 import types
 import decimal
 import unittest
+import warnings
 from test import support
 from test.support.os_helper import temp_cwd
 from test.support.script_helper import assert_python_failure, assert_python_ok
@@ -772,7 +773,7 @@ x = (
         self.assertEqual(f'{CustomFormat():\n}', '\n')
         self.assertEqual(f'{CustomFormat():\u2603}', '☃')
         with self.assertWarns(SyntaxWarning):
-            exec('f"{F():¯\_(ツ)_/¯}"', {'F': CustomFormat})
+            exec(r'f"{F():¯\_(ツ)_/¯}"', {'F': CustomFormat})
 
     def test_side_effect_order(self):
         class X:
@@ -904,7 +905,7 @@ x = (
         self.assertEqual(f'2\x203', '2 3')
         self.assertEqual(f'\x203', ' 3')
 
-        with self.assertWarns(DeprecationWarning):  # invalid escape sequence
+        with self.assertWarns(SyntaxWarning):  # invalid escape sequence
             value = eval(r"f'\{6*7}'")
         self.assertEqual(value, '\\42')
         with self.assertWarns(SyntaxWarning):  # invalid escape sequence
@@ -1037,7 +1038,7 @@ x = (
         ]
         for case, expected_result in deprecated_cases:
             with self.subTest(case=case, expected_result=expected_result):
-                with self.assertWarns(DeprecationWarning):
+                with self.assertWarns(SyntaxWarning):
                     result = eval(case)
                 self.assertEqual(result, expected_result)
         self.assertEqual(fr'\{{\}}', '\\{\\}')
@@ -1046,6 +1047,12 @@ x = (
         self.assertEqual(fr'\}}{1+1}', '\\}2')
         self.assertEqual(fr'{1+1}\}}', '2\\}')
 
+    def test_fstring_backslash_before_double_bracket_warns_once(self):
+        with warnings.catch_warnings(record=True) as w:
+            eval(r"f'\{{'")
+        self.assertEqual(len(w), 1)
+        self.assertEqual(w[0].category, SyntaxWarning)
+
     def test_fstring_backslash_prefix_raw(self):
         self.assertEqual(f'\\', '\\')
         self.assertEqual(f'\\\\', '\\\\')
diff --git a/Lib/test/test_future.py b/Lib/test/test_future.py
index b8b591a..4730bfa 100644
--- a/Lib/test/test_future.py
+++ b/Lib/test/test_future.py
@@ -4,6 +4,7 @@ import __future__
 import ast
 import unittest
 from test.support import import_helper
+from test.support.script_helper import spawn_python, kill_python
 from textwrap import dedent
 import os
 import re
@@ -121,6 +122,13 @@ class FutureTest(unittest.TestCase):
         exec("from __future__ import unicode_literals; x = ''", {}, scope)
         self.assertIsInstance(scope["x"], str)
 
+    def test_syntactical_future_repl(self):
+        p = spawn_python('-i')
+        p.stdin.write(b"from __future__ import barry_as_FLUFL\n")
+        p.stdin.write(b"2 <> 3\n")
+        out = kill_python(p)
+        self.assertNotIn(b'SyntaxError: invalid syntax', out)
+
 class AnnotationsFutureTestCase(unittest.TestCase):
     template = dedent(
         """
diff --git a/Misc/NEWS.d/next/Core and Builtins/2023-06-19-11-04-01.gh-issue-105908.7oanny.rst b/Misc/NEWS.d/next/Core and Builtins/2023-06-19-11-04-01.gh-issue-105908.7oanny.rst
new file mode 100644
index 0000000..03db3f0
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2023-06-19-11-04-01.gh-issue-105908.7oanny.rst
@@ -0,0 +1 @@
+Fixed bug where :gh:`99111` breaks future import ``barry_as_FLUFL`` in the Python REPL.
diff --git a/Parser/string_parser.c b/Parser/string_parser.c
index d4ce338..20459e8 100644
--- a/Parser/string_parser.c
+++ b/Parser/string_parser.c
@@ -12,6 +12,11 @@ static int
 warn_invalid_escape_sequence(Parser *p, const char *first_invalid_escape, Token *t)
 {
     unsigned char c = *first_invalid_escape;
+    if ((t->type == FSTRING_MIDDLE || t->type == FSTRING_END) && (c == '{' || c == '}')) {  // in this case the tokenizer has already emitted a warning,
+                                                                                            // see tokenizer.c:warn_invalid_escape_sequence
+        return 0;
+    }
+
     int octal = ('4' <= c && c <= '7');
     PyObject *msg =
         octal
@@ -31,7 +36,7 @@ warn_invalid_escape_sequence(Parser *p, const char *first_invalid_escape, Token
     if (PyErr_WarnExplicitObject(category, msg, p->tok->filename,
                                  t->lineno, NULL, NULL) < 0) {
         if (PyErr_ExceptionMatches(category)) {
-            /* Replace the DeprecationWarning exception with a SyntaxError
+            /* Replace the Syntax/DeprecationWarning exception with a SyntaxError
                to get a more accurate error report */
             PyErr_Clear();
 
diff --git a/Parser/tokenizer.c b/Parser/tokenizer.c
index 1a59f54..115b497 100644
--- a/Parser/tokenizer.c
+++ b/Parser/tokenizer.c
@@ -1559,12 +1559,12 @@ warn_invalid_escape_sequence(struct tok_state *tok, int first_invalid_escape_cha
         return -1;
     }
 
-    if (PyErr_WarnExplicitObject(PyExc_DeprecationWarning, msg, tok->filename,
+    if (PyErr_WarnExplicitObject(PyExc_SyntaxWarning, msg, tok->filename,
                                  tok->lineno, NULL, NULL) < 0) {
         Py_DECREF(msg);
 
-        if (PyErr_ExceptionMatches(PyExc_DeprecationWarning)) {
-            /* Replace the DeprecationWarning exception with a SyntaxError
+        if (PyErr_ExceptionMatches(PyExc_SyntaxWarning)) {
+            /* Replace the SyntaxWarning exception with a SyntaxError
                to get a more accurate error report */
             PyErr_Clear();
             return syntaxerror(tok, "invalid escape sequence '\\%c'", (char) first_invalid_escape_char);
diff --git a/Python/compile.c b/Python/compile.c
index f593e95..a8d0016 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -510,8 +510,10 @@ static PyCodeObject *optimize_and_assemble(struct compiler *, int addNone);
 
 static int
 compiler_setup(struct compiler *c, mod_ty mod, PyObject *filename,
-               PyCompilerFlags flags, int optimize, PyArena *arena)
+               PyCompilerFlags *flags, int optimize, PyArena *arena)
 {
+    PyCompilerFlags local_flags = _PyCompilerFlags_INIT;
+
     c->c_const_cache = PyDict_New();
     if (!c->c_const_cache) {
         return ERROR;
@@ -527,10 +529,13 @@ compiler_setup(struct compiler *c, mod_ty mod, PyObject *filename,
     if (!_PyFuture_FromAST(mod, filename, &c->c_future)) {
         return ERROR;
     }
-    int merged = c->c_future.ff_features | flags.cf_flags;
+    if (!flags) {
+        flags = &local_flags;
+    }
+    int merged = c->c_future.ff_features | flags->cf_flags;
     c->c_future.ff_features = merged;
-    flags.cf_flags = merged;
-    c->c_flags = flags;
+    flags->cf_flags = merged;
+    c->c_flags = *flags;
     c->c_optimize = (optimize == -1) ? _Py_GetConfig()->optimization_level : optimize;
     c->c_nestlevel = 0;
 
@@ -555,12 +560,11 @@ static struct compiler*
 new_compiler(mod_ty mod, PyObject *filename, PyCompilerFlags *pflags,
              int optimize, PyArena *arena)
 {
-    PyCompilerFlags flags = pflags ? *pflags : _PyCompilerFlags_INIT;
     struct compiler *c = PyMem_Calloc(1, sizeof(struct compiler));
     if (c == NULL) {
         return NULL;
     }
-    if (compiler_setup(c, mod, filename, flags, optimize, arena) < 0) {
+    if (compiler_setup(c, mod, filename, pflags, optimize, arena) < 0) {
         compiler_free(c);
         return NULL;
     }