gh-149167: PyREPL autocomplete imports to only display public members

Adds a mechanism that filters a module's public members for showing on autocomplete.

Author: edvilme

Lib/_pyrepl/_module_completer.py

@@ -221,7 +221,10 @@ def _find_attributes(
         if not imported_module:
             return [], None, self._get_import_completion_action(path)
         try:
-            module_attributes = dir(imported_module)
+            if hasattr(imported_module, '__all__'): # Use __all__ if available, otherwise use dir()
+                module_attributes = imported_module.__all__
+            else:
+                module_attributes = dir(imported_module)
         except Exception:
             module_attributes = []
         # Filter out invalid attribute names, such as dashes that cannot be

Lib/test/test_pyrepl/test_pyrepl.py

@@ -2,6 +2,7 @@
 import importlib
 import io
 import itertools
+lazy import json
 import os
 import pathlib
 import pkgutil
@@ -1767,6 +1768,23 @@ def test_colorize_import_completions(self) -> None:
         ])
         self.assertIsNone(action)
 
+    def test_find_attributes_uses_all(self):
+        """Test that _find_attributes respects __all__ when available."""
+        completer = ModuleCompleter()
+        
+        # json module has __all__ defined
+        attrs, module, _ = completer._find_attributes('json', '')
+        
+        # Should match __all__ contents, not dir() which includes methods
+        expected = sorted(json.__all__)
+        self.assertEqual(sorted(attrs), expected)
+        
+        # Should NOT contain __all__
+        self.assertNotIn('__all__', attrs)
+        
+        # Verify we got the actual module object
+        self.assertIs(module, sys.modules.get('json'))
+
 
 # Audit hook used to check for stdlib modules import side-effects
 # Defined globally to avoid adding one hook per test run (refleak)