#334: Don't wait for all rules before showing result

tests/conftest.py

@@ -1,6 +1,12 @@
 import pytest
+from mock import Mock
 
 
 @pytest.fixture
 def no_memoize(monkeypatch):
     monkeypatch.setattr('thefuck.utils.memoize.disabled', True)
+
+
+@pytest.fixture
+def settings():
+    return Mock(debug=False, no_colors=True)

tests/test_corrector.py

@@ -3,7 +3,7 @@ from pathlib import PosixPath, Path
 from mock import Mock
 from thefuck import corrector, conf, types
 from tests.utils import Rule, Command, CorrectedCommand
-from thefuck.corrector import make_corrected_commands, get_corrected_commands, remove_duplicates
+from thefuck.corrector import make_corrected_commands, get_corrected_commands
 
 
 def test_load_rule(mocker):
@@ -75,15 +75,6 @@ class TestGetCorrectedCommands(object):
                == [CorrectedCommand(script='test!', priority=100)]
 
 
-def test_remove_duplicates():
-    side_effect = lambda *_: None
-    assert set(remove_duplicates([CorrectedCommand('ls', priority=100),
-                                  CorrectedCommand('ls', priority=200),
-                                  CorrectedCommand('ls', side_effect, 300)])) \
-           == {CorrectedCommand('ls', priority=100),
-               CorrectedCommand('ls', side_effect, 300)}
-
-
 def test_get_corrected_commands(mocker):
     command = Command('test', 'test', 'test')
     rules = [Rule(match=lambda *_: False),
@@ -94,4 +85,4 @@ def test_get_corrected_commands(mocker):
                   priority=60)]
     mocker.patch('thefuck.corrector.get_rules', return_value=rules)
     assert [cmd.script for cmd in get_corrected_commands(command, None, Mock(debug=False))] \
-           == ['test@', 'test!', 'test;']
+           == ['test!', 'test@', 'test;']

tests/test_types.py

@@ -1,5 +1,6 @@
-from thefuck.types import RulesNamesList, Settings
+from thefuck.types import RulesNamesList, Settings, \
-from tests.utils import Rule
+    SortedCorrectedCommandsSequence
+from tests.utils import Rule, CorrectedCommand
 
 
 def test_rules_names_list():
@@ -15,3 +16,31 @@ def test_update_settings():
     assert new_settings.key == 'val'
     assert new_settings.unset == 'unset-value'
     assert settings.key == 'val'
+
+
+class TestSortedCorrectedCommandsSequence(object):
+    def test_realises_generator_only_on_demand(self, settings):
+        should_realise = False
+
+        def gen():
+            nonlocal should_realise
+            yield CorrectedCommand('git commit')
+            yield CorrectedCommand('git branch', priority=200)
+            assert should_realise
+            yield CorrectedCommand('git checkout', priority=100)
+
+        commands = SortedCorrectedCommandsSequence(gen(), settings)
+        assert commands[0] == CorrectedCommand('git commit')
+        should_realise = True
+        assert commands[1] == CorrectedCommand('git checkout', priority=100)
+        assert commands[2] == CorrectedCommand('git branch', priority=200)
+
+    def test_remove_duplicates(self, settings):
+        side_effect = lambda *_: None
+        seq = SortedCorrectedCommandsSequence(
+            iter([CorrectedCommand('ls', priority=100),
+                  CorrectedCommand('ls', priority=200),
+                  CorrectedCommand('ls', side_effect, 300)]),
+            settings)
+        assert set(seq) == {CorrectedCommand('ls', priority=100),
+                            CorrectedCommand('ls', side_effect, 300)}

tests/test_ui.py

@@ -4,7 +4,7 @@ from mock import Mock
 import pytest
 from itertools import islice
 from thefuck import ui
-from thefuck.types import CorrectedCommand
+from thefuck.types import CorrectedCommand, SortedCorrectedCommandsSequence
 
 
 @pytest.fixture
@@ -58,14 +58,18 @@ def test_command_selector():
 
 class TestSelectCommand(object):
     @pytest.fixture
-    def commands_with_side_effect(self):
+    def commands_with_side_effect(self, settings):
-        return [CorrectedCommand('ls', lambda *_: None, 100),
+        return SortedCorrectedCommandsSequence(
-                CorrectedCommand('cd', lambda *_: None, 100)]
+            iter([CorrectedCommand('ls', lambda *_: None, 100),
+                  CorrectedCommand('cd', lambda *_: None, 100)]),
+            settings)
 
     @pytest.fixture
-    def commands(self):
+    def commands(self, settings):
-        return [CorrectedCommand('ls', None, 100),
+        return SortedCorrectedCommandsSequence(
-                CorrectedCommand('cd', None, 100)]
+            iter([CorrectedCommand('ls', None, 100),
+                  CorrectedCommand('cd', None, 100)]),
+            settings)
 
     def test_without_commands(self, capsys):
         assert ui.select_command([], Mock(debug=False, no_color=True)) is None
@@ -92,9 +96,11 @@ class TestSelectCommand(object):
                                       require_confirmation=True)) == commands[0]
         assert capsys.readouterr() == ('', u'\x1b[1K\rls [enter/↑/↓/ctrl+c]\n')
 
-    def test_with_confirmation_one_match(self, capsys, patch_getch, commands):
+    def test_with_confirmation_one_match(self, capsys, patch_getch, commands,
+                                         settings):
         patch_getch(['\n'])
-        assert ui.select_command((commands[0],),
+        seq = SortedCorrectedCommandsSequence(iter([commands[0]]), settings)
+        assert ui.select_command(seq,
                                  Mock(debug=False, no_color=True,
                                       require_confirmation=True)) == commands[0]
         assert capsys.readouterr() == ('', u'\x1b[1K\rls [enter/ctrl+c]\n')

thefuck/corrector.py

@@ -2,7 +2,6 @@ import sys
 from imp import load_source
 from pathlib import Path
 from . import conf, types, logs
-from .utils import eager
 
 
 def load_rule(rule, settings):
@@ -27,17 +26,16 @@ def get_loaded_rules(rules, settings):
                 yield loaded_rule
 
 
-@eager
 def get_rules(user_dir, settings):
     """Returns all enabled rules."""
     bundled = Path(__file__).parent \
         .joinpath('rules') \
         .glob('*.py')
     user = user_dir.joinpath('rules').glob('*.py')
-    return get_loaded_rules(sorted(bundled) + sorted(user), settings)
+    return sorted(get_loaded_rules(sorted(bundled) + sorted(user), settings),
+                  key=lambda rule: rule.priority)
 
 
-@eager
 def get_matched_rules(command, rules, settings):
     """Returns first matched rule for command."""
     script_only = command.stdout is None and command.stderr is None
@@ -66,22 +64,8 @@ def make_corrected_commands(command, rules, settings):
                                          priority=(n + 1) * rule.priority)
 
 
-def remove_duplicates(corrected_commands):
-    commands = {(command.script, command.side_effect): command
-                for command in sorted(corrected_commands,
-                                      key=lambda command: -command.priority)}
-    return commands.values()
-
-
 def get_corrected_commands(command, user_dir, settings):
     rules = get_rules(user_dir, settings)
-    logs.debug(
-        u'Loaded rules: {}'.format(', '.join(rule.name for rule in rules)),
-        settings)
     matched = get_matched_rules(command, rules, settings)
-    logs.debug(
-        u'Matched rules: {}'.format(', '.join(rule.name for rule in matched)),
-        settings)
     corrected_commands = make_corrected_commands(command, matched, settings)
-    return sorted(remove_duplicates(corrected_commands),
+    return types.SortedCorrectedCommandsSequence(corrected_commands, settings)
-                  key=lambda corrected_command: corrected_command.priority)

thefuck/types.py

@@ -1,5 +1,6 @@
 from collections import namedtuple
-
+from traceback import format_stack
+from .logs import debug
 
 Command = namedtuple('Command', ('script', 'stdout', 'stderr'))
 
@@ -18,7 +19,6 @@ class RulesNamesList(list):
 
 
 class Settings(dict):
-
     def __getattr__(self, item):
         return self.get(item)
 
@@ -29,3 +29,73 @@ class Settings(dict):
         conf = dict(kwargs)
         conf.update(self)
         return Settings(conf)
+
+
+class SortedCorrectedCommandsSequence(object):
+    """List-like collection/wrapper around generator, that:
+
+    - immediately gives access to the first commands through [];
+    - realises generator and sorts commands on first access to other
+      commands through [], or when len called.
+
+    """
+
+    def __init__(self, commands, settings):
+        self._settings = settings
+        self._commands = commands
+        self._cached = self._get_first_two_unique()
+        self._realised = False
+
+    def _get_first_two_unique(self):
+        """Returns first two unique commands."""
+        try:
+            first = next(self._commands)
+        except StopIteration:
+            return []
+
+        for command in self._commands:
+            if command.script != first.script or \
+                            command.side_effect != first.side_effect:
+                return [first, command]
+        return [first]
+
+    def _remove_duplicates(self, corrected_commands):
+        """Removes low-priority duplicates."""
+        commands = {(command.script, command.side_effect): command
+                    for command in sorted(corrected_commands,
+                                          key=lambda command: -command.priority)
+                    if command.script != self._cached[0].script
+                    or command.side_effect != self._cached[0].side_effect}
+        return commands.values()
+
+    def _realise(self):
+        """Realises generator, removes duplicates and sorts commands."""
+        commands = self._cached[1:] + list(self._commands)
+        commands = self._remove_duplicates(commands)
+        self._cached = [self._cached[0]] + sorted(
+            commands, key=lambda corrected_command: corrected_command.priority)
+        self._realised = True
+        debug('SortedCommandsSequence was realised with: {}, after: {}'.format(
+            self._cached, '\n'.join(format_stack())), self._settings)
+
+    def __getitem__(self, item):
+        if item != 0 and not self._realised:
+            self._realise()
+        return self._cached[item]
+
+    def __bool__(self):
+        return bool(self._cached)
+
+    def __len__(self):
+        if not self._realised:
+            self._realise()
+        return len(self._cached)
+
+    def __iter__(self):
+        if not self._realised:
+            self._realise()
+        return iter(self._cached)
+
+    @property
+    def is_multiple(self):
+        return len(self._cached) > 1

thefuck/ui.py

@@ -88,9 +88,9 @@ def select_command(corrected_commands, settings):
         logs.show_corrected_command(selector.value, settings)
         return selector.value
 
-    multiple_cmds = len(corrected_commands) > 1
+    selector.on_change(
-
+        lambda val: logs.confirm_text(val, corrected_commands.is_multiple,
-    selector.on_change(lambda val: logs.confirm_text(val, multiple_cmds, settings))
+                                      settings))
     for action in read_actions():
         if action == SELECT:
             sys.stderr.write('\n')