⚡️ Speed up method HardwareHandlerBase.get_gui_thread by 20%

[codeflash-ai]

📄 20% (0.20x) speedup for HardwareHandlerBase.get_gui_thread in electrum/hw_wallet/plugin.py

⏱️ Runtime : 358 microseconds → 299 microseconds (best of 357 runs)

📝 Explanation and details

The optimized code achieves a 20% speedup by eliminating expensive exception handling overhead in favor of Python's built-in getattr() function with a default value.

Key optimizations:

1. Replaced try/except with getattr(): The original code used a try/except block to handle AttributeError when accessing self.win.gui_thread. The optimized version uses getattr(win, "gui_thread", None), which internally handles missing attributes without raising exceptions.

2. Cached attribute access: Added win = self.win to avoid accessing self.win multiple times, reducing attribute lookup overhead.

Why this is faster:

• Exception handling in Python has significant overhead - creating, raising, and catching exceptions involves stack unwinding and object creation
• getattr() is implemented in C and uses Python's internal attribute lookup mechanism, which is much faster than exception handling
• The optimization eliminates ~177 AttributeError exceptions per 1620 calls (11% exception rate) based on the profiler data

Performance benefits by test case:

• Biggest gains (100%+ faster): Cases where win lacks gui_thread attribute (missing attributes, built-in types like int, objects with __slots__)
• Moderate gains (8-25% faster): Cases with property-based gui_thread that raises AttributeError
• Minimal impact: Cases where gui_thread exists and works normally

This optimization is particularly effective for codebases where attribute access failures are common, as it converts expensive exception-based control flow into efficient built-in function calls.

✅ Correctness verification report:

Test	Status
⚙️ Existing Unit Tests	🔘 None Found
🌀 Generated Regression Tests	✅ 2136 Passed
⏪ Replay Tests	🔘 None Found
🔎 Concolic Coverage Tests	🔘 None Found
📊 Tests Coverage	100.0%

🌀 Generated Regression Tests and Runtime

import threading # imports import pytest # used for our unit tests from electrum.hw_wallet.plugin import HardwareHandlerBase # =========================== # Unit tests for get_gui_thread # =========================== # ----- Basic Test Cases ----- def test_get_gui_thread_with_win_none(): """Test when win is None (default).""" handler = HardwareHandlerBase() handler.win = None # Should return None codeflash_output = handler.get_gui_thread() # 385ns -> 395ns (2.53% slower) def test_get_gui_thread_with_win_missing_gui_thread(): """Test when win is set but has no gui_thread attribute.""" class DummyWin: pass # No gui_thread handler = HardwareHandlerBase() handler.win = DummyWin() # Should return None since gui_thread is missing codeflash_output = handler.get_gui_thread() # 1.24μs -> 618ns (101% faster) # ----- Edge Test Cases ----- def test_get_gui_thread_with_win_gui_thread_is_none(): """Test when win.gui_thread is explicitly set to None.""" class DummyWin: def __init__(self): self.gui_thread = None handler = HardwareHandlerBase() handler.win = DummyWin() # Should return None (since gui_thread is None) codeflash_output = handler.get_gui_thread() # 470ns -> 467ns (0.642% faster) def test_get_gui_thread_with_win_gui_thread_is_not_thread(): """Test when win.gui_thread is set to a non-thread object.""" class DummyWin: def __init__(self): self.gui_thread = "not_a_thread" handler = HardwareHandlerBase() handler.win = DummyWin() # Should return the value, even if it's not a thread (function does not type-check) codeflash_output = handler.get_gui_thread() # 476ns -> 466ns (2.15% faster) def test_get_gui_thread_with_win_is_int(): """Test when win is set to an integer (not an object with gui_thread).""" handler = HardwareHandlerBase() handler.win = 42 # Should return None, since int has no gui_thread attribute codeflash_output = handler.get_gui_thread() # 1.12μs -> 460ns (143% faster) def test_get_gui_thread_with_win_is_object_with_property_exception(): """Test when win.gui_thread property raises an exception other than AttributeError.""" class DummyWin: @property def gui_thread(self): raise RuntimeError("Some error") handler = HardwareHandlerBase() handler.win = DummyWin() # Should propagate exceptions other than AttributeError with pytest.raises(RuntimeError): handler.get_gui_thread() # 1.52μs -> 1.41μs (7.94% faster) def test_get_gui_thread_with_win_is_object_with_gui_thread_as_property_missing(): """Test when win.gui_thread is a property that raises AttributeError.""" class DummyWin: @property def gui_thread(self): raise AttributeError("Missing gui_thread") handler = HardwareHandlerBase() handler.win = DummyWin() # Should catch AttributeError and return None codeflash_output = handler.get_gui_thread() # 1.38μs -> 1.11μs (24.1% faster) # ----- Large Scale Test Cases ----- def test_get_gui_thread_large_scale_with_non_thread_gui_thread(): """Test with large number of handlers with gui_thread set to non-thread objects.""" class DummyWin: def __init__(self, val): self.gui_thread = val vals = [str(i) for i in range(500)] handlers = [] for v in vals: h = HardwareHandlerBase() h.win = DummyWin(v) handlers.append(h) # All should return their respective string value for h, v in zip(handlers, vals): codeflash_output = h.get_gui_thread() # 88.6μs -> 85.7μs (3.35% faster) # codeflash_output is used to check that the output of the original code is the same as that of the optimized code. #------------------------------------------------ import threading # imports import pytest from electrum.hw_wallet.plugin import HardwareHandlerBase # --------------------------- # Unit tests for get_gui_thread # --------------------------- # Basic test cases def test_get_gui_thread_returns_none_when_win_is_none(): # Scenario: win is None handler = HardwareHandlerBase() handler.win = None # Should return None codeflash_output = handler.get_gui_thread() # 335ns -> 365ns (8.22% slower) def test_get_gui_thread_returns_none_when_win_has_no_gui_thread(): # Scenario: win is set but has no gui_thread attribute handler = HardwareHandlerBase() class DummyWin: pass handler.win = DummyWin() # Should return None codeflash_output = handler.get_gui_thread() # 1.11μs -> 542ns (105% faster) # Edge test cases def test_get_gui_thread_returns_none_when_win_gui_thread_is_none(): # Scenario: win is set, gui_thread attribute exists but is None handler = HardwareHandlerBase() class DummyWin: pass win = DummyWin() win.gui_thread = None handler.win = win # Should return None (since gui_thread is None) codeflash_output = handler.get_gui_thread() # 459ns -> 422ns (8.77% faster) def test_get_gui_thread_returns_non_thread_object(): # Scenario: win is set, gui_thread attribute exists but is not a Thread object handler = HardwareHandlerBase() class DummyWin: pass win = DummyWin() win.gui_thread = "not_a_thread" handler.win = win # Should return the value, even if it's not a Thread codeflash_output = handler.get_gui_thread() # 431ns -> 448ns (3.79% slower) def test_get_gui_thread_with_win_as_object_with_slots(): # Scenario: win is an object with __slots__ but no gui_thread handler = HardwareHandlerBase() class SlotWin: __slots__ = () handler.win = SlotWin() # Should return None, not raise AttributeError codeflash_output = handler.get_gui_thread() # 1.09μs -> 541ns (101% faster) def test_get_gui_thread_with_win_as_builtin_type(): # Scenario: win is a built-in type (e.g. int) handler = HardwareHandlerBase() handler.win = 42 # Should return None, not raise AttributeError codeflash_output = handler.get_gui_thread() # 1.12μs -> 438ns (155% faster) def test_get_gui_thread_with_win_as_dict(): # Scenario: win is a dict, which does not have gui_thread attribute handler = HardwareHandlerBase() handler.win = {} # Should return None, not raise AttributeError codeflash_output = handler.get_gui_thread() # 1.02μs -> 420ns (143% faster) def test_get_gui_thread_with_win_has_gui_thread_property_raises(): # Scenario: win.gui_thread is a property that raises AttributeError handler = HardwareHandlerBase() class WinRaises: @property def gui_thread(self): raise AttributeError("no gui_thread") handler.win = WinRaises() # Should return None, not propagate the exception codeflash_output = handler.get_gui_thread() # 1.40μs -> 1.12μs (25.0% faster) def test_get_gui_thread_with_win_has_gui_thread_property_raises_other_exception(): # Scenario: win.gui_thread is a property that raises a non-AttributeError handler = HardwareHandlerBase() class WinRaises: @property def gui_thread(self): raise RuntimeError("unexpected error") handler.win = WinRaises() # Should propagate the exception, as only AttributeError is caught with pytest.raises(RuntimeError): handler.get_gui_thread() # 1.41μs -> 1.40μs (1.15% faster) # Large scale test cases

To edit these changes git checkout codeflash/optimize-HardwareHandlerBase.get_gui_thread-mhh0slvr and push.