gh-130472: Remove readline-only hacks from PyREPL completions

Lib/_pyrepl/fancycompleter.py

@@ -105,9 +105,6 @@ def attr_matches(self, text):
         names = [f'{expr}.{name}' for name in names]
         if self.use_colors:
             return self.colorize_matches(names, values)
-
-        if prefix:
-            names.append(' ')
         return names
 
     def _attr_matches(self, text):
@@ -173,21 +170,15 @@ def _attr_matches(self, text):
         return expr, attr, names, values
 
     def colorize_matches(self, names, values):
-        matches = [self._color_for_obj(i, name, obj)
-                   for i, (name, obj)
-                   in enumerate(zip(names, values))]
-        # We add a space at the end to prevent the automatic completion of the
-        # common prefix, which is the ANSI escape sequence.
-        matches.append(' ')
-        return matches
-
-    def _color_for_obj(self, i, name, value):
+        return [
+            self._color_for_obj(name, obj)
+            for name, obj in zip(names, values)
+        ]
+
+    def _color_for_obj(self, name, value):
         t = type(value)
         color = self._color_by_type(t)
-        # Encode the match index into a fake escape sequence that
-        # stripcolor() can still remove once i reaches four digits.
-        N = f"\x1b[{i // 100:03d};{i % 100:02d}m"
-        return f"{N}{color}{name}{ANSIColors.RESET}"
+        return f"{color}{name}{ANSIColors.RESET}"
 
     def _color_by_type(self, t):
         typename = t.__name__

Lib/_pyrepl/readline.py

@@ -37,7 +37,7 @@
 from rlcompleter import Completer as RLCompleter
 
 from . import commands, historical_reader
-from .completing_reader import CompletingReader
+from .completing_reader import CompletingReader, stripcolor
 from .console import Console as ConsoleType
 from ._module_completer import ModuleCompleter, make_default_module_completer
 from .fancycompleter import Completer as FancyCompleter
@@ -163,9 +163,9 @@ def get_completions(self, stem: str) -> tuple[list[str], CompletionAction | None
                     break
                 result.append(next)
                 state += 1
-            # emulate the behavior of the standard readline that sorts
-            # the completions before displaying them.
-            result.sort()
+            # Emulate readline's sorting using the visible text rather than
+            # the raw ANSI escape sequences used for colorized matches.
+            result.sort(key=stripcolor)
         return result, None
 
     def get_module_completions(self) -> tuple[list[str], CompletionAction | None] | None:

Lib/test/test_pyrepl/test_fancycompleter.py

@@ -55,7 +55,7 @@ class C(object):
         self.assertEqual(compl.attr_matches('a.'), ['a.attr', 'a.mro'])
         self.assertEqual(
             compl.attr_matches('a._'),
-            ['a._C__attr__attr', 'a._attr', ' '],
+            ['a._C__attr__attr', 'a._attr'],
         )
         matches = compl.attr_matches('a.__')
         self.assertNotIn('__class__', matches)
@@ -79,7 +79,7 @@ def test_complete_attribute_colored(self):
                 break
         else:
             self.assertFalse(True, matches)
-        self.assertIn(' ', matches)
+        self.assertNotIn(' ', matches)
 
     def test_preserves_callable_postfix_for_single_attribute_match(self):
         compl = Completer({'os': os}, use_colors=False)
@@ -159,22 +159,17 @@ def test_complete_global_colored(self):
         self.assertEqual(compl.global_matches('foo'), ['fooba'])
         matches = compl.global_matches('fooba')
 
-        # these are the fake escape sequences which are needed so that
-        # readline displays the matches in the proper order
-        N0 = f"\x1b[000;00m"
-        N1 = f"\x1b[000;01m"
         int_color = theme.fancycompleter.int
-        self.assertEqual(set(matches), {
-            ' ',
-            f'{N0}{int_color}foobar{ANSIColors.RESET}',
-            f'{N1}{int_color}foobazzz{ANSIColors.RESET}',
-        })
+        self.assertEqual(matches, [
+            f'{int_color}foobar{ANSIColors.RESET}',
+            f'{int_color}foobazzz{ANSIColors.RESET}',
+        ])
         self.assertEqual(compl.global_matches('foobaz'), ['foobazzz'])
         self.assertEqual(compl.global_matches('nothing'), [])
 
-    def test_large_color_sort_prefix_is_stripped(self):
+    def test_colorized_match_is_stripped(self):
         compl = Completer({'a': 42}, use_colors=True)
-        match = compl._color_for_obj(1000, 'spam', 1)
+        match = compl._color_for_obj('spam', 1)
         self.assertEqual(stripcolor(match), 'spam')
 
     def test_complete_with_indexer(self):
@@ -197,27 +192,24 @@ class A:
         compl = Completer({'A': A}, use_colors=False)
         #
         # In this case, we want to display all attributes which start with
-        # 'a'. Moreover, we also include a space to prevent readline to
-        # automatically insert the common prefix (which will the the ANSI escape
-        # sequence if we use colors).
+        # 'a'.
         matches = compl.attr_matches('A.a')
         self.assertEqual(
             sorted(matches),
-            [' ', 'A.aaa', 'A.abc_1', 'A.abc_2', 'A.abc_3'],
+            ['A.aaa', 'A.abc_1', 'A.abc_2', 'A.abc_3'],
         )
         #
         # If there is an actual common prefix, we return just it, so that readline
         # will insert it into place
         matches = compl.attr_matches('A.ab')
         self.assertEqual(matches, ['A.abc_'])
         #
-        # Finally, at the next tab, we display again all the completions available
-        # for this common prefix. Again, we insert a spurious space to prevent the
-        # automatic completion of ANSI sequences.
+        # Finally, at the next tab, we display again all the completions
+        # available for this common prefix.
         matches = compl.attr_matches('A.abc_')
         self.assertEqual(
             sorted(matches),
-            [' ', 'A.abc_1', 'A.abc_2', 'A.abc_3'],
+            ['A.abc_1', 'A.abc_2', 'A.abc_3'],
         )
 
     def test_complete_exception(self):

Lib/test/test_pyrepl/test_pyrepl.py

@@ -36,6 +36,7 @@
     code_to_events,
 )
 from _pyrepl.console import Event
+from _pyrepl.completing_reader import stripcolor
 from _pyrepl._module_completer import (
     ImportParser,
     ModuleCompleter,
@@ -999,6 +1000,27 @@ class Obj:
         self.assertNotIn("banana", menu)
         self.assertNotIn("mro", menu)
 
+    def test_get_completions_sorts_colored_matches_by_visible_text(self):
+        console = FakeConsole(iter(()))
+        config = ReadlineConfig()
+        config.readline_completer = FancyCompleter(
+            {
+                "foo_str": "value",
+                "foo_int": 1,
+                "foo_none": None,
+            },
+            use_colors=True,
+        ).complete
+        reader = ReadlineAlikeReader(console=console, config=config)
+
+        matches, action = reader.get_completions("foo_")
+
+        self.assertIsNone(action)
+        self.assertEqual(
+            [stripcolor(match) for match in matches],
+            ["foo_int", "foo_none", "foo_str"],
+        )
+
 
 class TestPyReplReadlineSetup(TestCase):
     def test_setup_ignores_basic_completer_env_when_env_is_disabled(self):