gh-119443: Turn off from __future__ import annotations in REPL (#119493)

Author: JelleZijlstra

Lib/_pyrepl/simple_interact.py

@@ -100,7 +100,7 @@ def runsource(self, source, filename="<input>", symbol="single"):
             the_symbol = symbol if stmt is last_stmt else "exec"
             item = wrapper([stmt])
             try:
-                code = compile(item, filename, the_symbol)
+                code = compile(item, filename, the_symbol, dont_inherit=True)
             except (OverflowError, ValueError):
                     self.showsyntaxerror(filename)
                     return False

Lib/test/test_pyrepl/test_interact.py

@@ -94,3 +94,12 @@ def test_runsource_shows_syntax_error_for_failed_compilation(self):
         with patch.object(console, "showsyntaxerror") as mock_showsyntaxerror:
             console.runsource(source)
             mock_showsyntaxerror.assert_called_once()
+
+    def test_no_active_future(self):
+        console = InteractiveColoredConsole()
+        source = "x: int = 1; print(__annotations__)"
+        f = io.StringIO()
+        with contextlib.redirect_stdout(f):
+            result = console.runsource(source)
+        self.assertFalse(result)
+        self.assertEqual(f.getvalue(), "{'x': <class 'int'>}\n")

Misc/NEWS.d/next/Library/2024-05-23-22-29-59.gh-issue-119443.KAGz6S.rst

@@ -0,0 +1,2 @@
+The interactive REPL no longer runs with ``from __future__ import
+annotations`` enabled. Patch by Jelle Zijlstra.