diff --git a/Lib/test/test_fstring.py b/Lib/test/test_fstring.py
index ba223ae124a8fb..cb14bba2602def 100644
--- a/Lib/test/test_fstring.py
+++ b/Lib/test/test_fstring.py
@@ -496,6 +496,24 @@ def test_ast_line_numbers_with_parentheses(self):
self.assertEqual(wat2.end_col_offset, 17)
self.assertEqual(fstring.end_col_offset, 18)
+ def test_ast_fstring_empty_format_spec(self):
+ expr = "f'{expr:}'"
+
+ mod = ast.parse(expr)
+ self.assertEqual(type(mod), ast.Module)
+ self.assertEqual(len(mod.body), 1)
+
+ fstring = mod.body[0].value
+ self.assertEqual(type(fstring), ast.JoinedStr)
+ self.assertEqual(len(fstring.values), 1)
+
+ fv = fstring.values[0]
+ self.assertEqual(type(fv), ast.FormattedValue)
+
+ format_spec = fv.format_spec
+ self.assertEqual(type(format_spec), ast.JoinedStr)
+ self.assertEqual(len(format_spec.values), 0)
+
def test_docstring(self):
def f():
f'''Not a docstring'''
diff --git a/Misc/NEWS.d/next/Core and Builtins/2023-07-04-09-51-45.gh-issue-106396.DmYp7x.rst b/Misc/NEWS.d/next/Core and Builtins/2023-07-04-09-51-45.gh-issue-106396.DmYp7x.rst
new file mode 100644
index 00000000000000..c5767e97271d9d
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2023-07-04-09-51-45.gh-issue-106396.DmYp7x.rst
@@ -0,0 +1,3 @@
+When the format specification of an f-string expression is empty, the parser now
+generates an empty :class:`ast.JoinedStr` node for it instead of an one-element
+:class:`ast.JoinedStr` with an empty string :class:`ast.Constant`.
diff --git a/Parser/action_helpers.c b/Parser/action_helpers.c
index 70c267bb212fcb..36e0750220a30d 100644
--- a/Parser/action_helpers.c
+++ b/Parser/action_helpers.c
@@ -997,6 +997,18 @@ _PyPegen_setup_full_format_spec(Parser *p, Token *colon, asdl_expr_seq *spec, in
if (!spec) {
return NULL;
}
+
+ // This is needed to keep compatibility with 3.11, where an empty format spec is parsed
+ // as an *empty* JoinedStr node, instead of having an empty constant in it.
+ if (asdl_seq_LEN(spec) == 1) {
+ expr_ty e = asdl_seq_GET(spec, 0);
+ if (e->kind == Constant_kind
+ && PyUnicode_Check(e->v.Constant.value)
+ && PyUnicode_GetLength(e->v.Constant.value) == 0) {
+ spec = _Py_asdl_expr_seq_new(0, arena);
+ }
+ }
+
expr_ty res = _PyAST_JoinedStr(spec, lineno, col_offset, end_lineno, end_col_offset, p->arena);
if (!res) {
return NULL;
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