gh-124960: Fixed barry_as_FLUFL future flag does not work in new REPL

Lib/_pyrepl/console.py

@@ -160,6 +160,13 @@ def __init__(
     ) -> None:
         super().__init__(locals=locals, filename=filename, local_exit=local_exit)  # type: ignore[call-arg]
         self.can_colorize = _colorize.can_colorize()
+        self.barry_as_FLUFL = False
+
+    def check_barry_as_FLUFL(self, tree):
+        for node in ast.walk(tree):
+            if isinstance(node, ast.ImportFrom) and node.module == "__future__":
+                if any(alias.name == "barry_as_FLUFL" for alias in node.names):
+                    self.barry_as_FLUFL = True
 
     def showsyntaxerror(self, filename=None, **kwargs):
         super().showsyntaxerror(filename=filename, **kwargs)
@@ -173,8 +180,11 @@ def _excepthook(self, typ, value, tb):
         self.write(''.join(lines))
 
     def runsource(self, source, filename="<input>", symbol="single"):
+        if self.barry_as_FLUFL:
+            source = source.replace("<>", "!=")
         try:
             tree = ast.parse(source)
+            self.check_barry_as_FLUFL(tree)
         except (SyntaxError, OverflowError, ValueError):
             self.showsyntaxerror(filename, source=source)
             return False

Lib/test/test_pyrepl/test_interact.py

@@ -102,6 +102,29 @@ def f(x, x): ...
 SyntaxError: duplicate argument 'x' in function definition"""
         self.assertIn(r, f.getvalue())
 
+    @force_not_colorized
+    def test_check_barry_as_FLUFL_show_syntax_error(self):
+        console = InteractiveColoredConsole()
+        source = "1 <> 2"
+        f = io.StringIO()
+        with contextlib.redirect_stderr(f):
+            result = console.runsource(source)
+        self.assertFalse(result)
+        r = """
+    1 <> 2
+      ^^
+SyntaxError: invalid syntax"""
+        self.assertIn(r, f.getvalue())
+
+    @force_not_colorized
+    def test_check_barry_as_FLUFL(self):
+        console = InteractiveColoredConsole()
+        source = "from __future__ import barry_as_FLUFL; 1 <> 2"
+        f = io.StringIO()
+        with contextlib.redirect_stderr(f):
+            result = console.runsource(source)
+        self.assertEqual(result, True)
+
     def test_runsource_shows_syntax_error_for_failed_compilation(self):
         console = InteractiveColoredConsole()
         source = "print('Hello, world!'"

Misc/NEWS.d/next/Library/2024-10-05-15-49-53.gh-issue-124960.Bol9hT.rst

@@ -0,0 +1,2 @@
+Fixed barry_as_FLUFL future flag does not work in new REPL. Patch by Jiahao
+Li