flake8-isort
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flake8-isort 100 times slower than isort
I'd like to use flake8-isort in my project, but I can't because it is extremely slow. Here is a script to reproduce the issue.
import os
import shutil
from pathlib import Path
from time import time
def prepare_files():
shutil.rmtree("files", ignore_errors=True)
Path("files").mkdir(exist_ok=True)
content = "\n".join(10000 * ["def a(): pass"])
for i in range(100):
Path(f"files/file{i:03d}.py").write_text(content)
def execute(cmd):
start = time()
os.system(cmd)
duration = time() - start
return duration
if __name__ == "__main__":
prepare_files()
isort_duration = execute("isort --check-only files")
print(f"isort: {isort_duration:.3f} sec")
flake8_duration = execute("flake8 --select I001,I002,I003,I004,I005 files")
print(f"flake8: {flake8_duration:.3f} sec")
print(f"ratio: {flake8_duration / isort_duration:.1f}")
I see following numbers on my machine (the same is on github actions).
isort: 2.511 sec
flake8: 394.109 sec
ratio: 157.0
Is it possible to do something with it?
Versions:
Python: 3.9.7
flake8: 3.9.2
flake8-isort: 4.0.0
isort: 5.9.3
interesting... did you run a profiler on it to check why it is so slow? 🤔 I'm really curious on what's the slow path here...
Nope
I profiled this briefly using the first 10 files from the attached test program:
> python -m cProfile -o flake8.prof -m flake8 -- --select I001,I002,I003,I004,I005 files/file00*.py
And the following profile output would seem to indicate that isort itself, and flake8-isort are still very fast. But flake8 is still parsing every file to run all the normal flake8 checks.
The time spent under flake8_isort, run
is 0.787s
40 0.003 0.000 0.787 0.020 ve/lib/python3.8/site-packages/flake8_isort.py:190(run)
And the time spent under isort.api, sort_stream
is 0.617s
10 0.000 0.000 0.617 0.062 ve/lib/python3.8/site-packages/isort/api.py:137(sort_stream)
But a full 61s is under flake8/checker.py run_checks
10 0.000 0.000 61.339 6.134 ve/lib/python3.8/site-packages/flake8/checker.py:593(run_checks)
And that time seems to break down mostly into, process_tokens
10 1.327 0.133 40.254 4.025 ve/lib/python3.8/site-packages/flake8/checker.py:565(process_tokens)
and run_ast_checks
.
10 0.045 0.004 21.085 2.108 ve/lib/python3.8/site-packages/flake8/checker.py:487(run_ast_checks)
More profile output:
>>> p = pstats.Stats("flake8.prof").sort_stats('cumtime').print_stats('pyflakes|flake8|isort', 0.1)
Mon Feb 28 10:18:57 2022 flake8.prof
105113153 function calls (103508954 primitive calls) in 64.613 seconds
Ordered by: cumulative time
List reduced from 1941 to 616 due to restriction <'pyflakes|flake8|isort'>
List reduced from 616 to 62 due to restriction <0.1>
ncalls tottime percall cumtime percall filename:lineno(function)
1 0.000 0.000 65.145 65.145 ve/lib/python3.8/site-packages/flake8/__main__.py:1(<module>)
1 0.000 0.000 65.118 65.118 ve/lib/python3.8/site-packages/flake8/main/cli.py:9(main)
1 0.000 0.000 65.115 65.115 ve/lib/python3.8/site-packages/flake8/main/application.py:367(run)
1 0.000 0.000 65.115 65.115 ve/lib/python3.8/site-packages/flake8/main/application.py:362(_run)
1 0.000 0.000 61.470 61.470 ve/lib/python3.8/site-packages/flake8/main/application.py:256(run_checks)
1 0.000 0.000 61.339 61.339 ve/lib/python3.8/site-packages/flake8/checker.py:297(run)
1 0.000 0.000 61.339 61.339 ve/lib/python3.8/site-packages/flake8/checker.py:292(run_serial)
10 0.000 0.000 61.339 6.134 ve/lib/python3.8/site-packages/flake8/checker.py:593(run_checks)
10 1.327 0.133 40.254 4.025 ve/lib/python3.8/site-packages/flake8/checker.py:565(process_tokens)
100000 0.149 0.000 27.190 0.000 ve/lib/python3.8/site-packages/flake8/checker.py:609(handle_newline)
100000 4.355 0.000 27.018 0.000 ve/lib/python3.8/site-packages/flake8/checker.py:508(run_logical_checks)
3600050 4.193 0.000 24.336 0.000 ve/lib/python3.8/site-packages/flake8/checker.py:403(run_check)
10 0.045 0.004 21.085 2.108 ve/lib/python3.8/site-packages/flake8/checker.py:487(run_ast_checks)
10 0.000 0.000 10.181 1.018 ve/lib/python3.8/site-packages/flake8/plugins/pyflakes.py:70(__init__)
10 0.035 0.003 10.180 1.018 ve/lib/python3.8/site-packages/pyflakes/checker.py:896(__init__)
200010/100010 0.280 0.000 7.546 0.000 ve/lib/python3.8/site-packages/pyflakes/checker.py:1368(handleChildren)
3600050 2.951 0.000 7.276 0.000 ve/lib/python3.8/site-packages/flake8/processor.py:242(keyword_arguments_for)
400000/300000 0.605 0.000 6.390 0.000 ve/lib/python3.8/site-packages/pyflakes/checker.py:1402(handleNode)
700010 0.538 0.000 4.777 0.000 ve/lib/python3.8/site-packages/flake8/processor.py:267(generate_tokens)
100000 0.198 0.000 4.415 0.000 ve/lib/python3.8/site-packages/pyflakes/checker.py:2103(FUNCTIONDEF)
700000 0.585 0.000 4.187 0.000 ve/lib/python3.8/site-packages/flake8/checker.py:622(check_physical_eol)
1 0.000 0.000 3.476 3.476 ve/lib/python3.8/site-packages/flake8/main/application.py:353(report)
1 0.000 0.000 3.476 3.476 ve/lib/python3.8/site-packages/flake8/main/application.py:301(report_errors)
1 0.001 0.001 3.476 3.476 ve/lib/python3.8/site-packages/flake8/checker.py:233(report)
12 0.130 0.011 3.387 0.282 ve/lib/python3.8/site-packages/flake8/checker.py:151(_handle_results)
20 0.093 0.005 3.262 0.163 ve/lib/python3.8/site-packages/pyflakes/checker.py:948(runDeferred)
200032 0.131 0.000 3.258 0.000 ve/lib/python3.8/site-packages/flake8/style_guide.py:397(handle_error)
20 0.092 0.005 3.245 0.162 ve/lib/python3.8/site-packages/flake8/processor.py:125(file_tokens)
200032 0.543 0.000 3.127 0.000 ve/lib/python3.8/site-packages/flake8/style_guide.py:530(handle_error)
100000 0.166 0.000 3.064 0.000 ve/lib/python3.8/site-packages/pyflakes/checker.py:2169(runFunction)
100000 0.487 0.000 2.898 0.000 ve/lib/python3.8/site-packages/flake8/checker.py:534(run_physical_checks)
700000 1.392 0.000 2.608 0.000 ve/lib/python3.8/site-packages/flake8/processor.py:417(log_token)
100000 0.427 0.000 2.530 0.000 ve/lib/python3.8/site-packages/pyflakes/checker.py:2117(LAMBDA)
100000 1.210 0.000 1.941 0.000 ve/lib/python3.8/site-packages/pyflakes/checker.py:784(in_annotation_func)
10 0.000 0.000 1.910 0.191 ve/lib/python3.8/site-packages/flake8/processor.py:221(build_ast)
10 0.000 0.000 1.847 0.185 ve/lib/python3.8/site-packages/flake8_plugin_utils/plugin.py:68(run)
10 0.099 0.010 1.769 0.177 ve/lib/python3.8/site-packages/pyflakes/checker.py:829(_collect_type_comments)
101570 0.600 0.000 1.650 0.000 ve/lib/python3.8/site-packages/pyflakes/checker.py:1119(addBinding)
100000 0.075 0.000 1.542 0.000 ve/lib/python3.8/site-packages/pyflakes/checker.py:818(_typeable)
200032 0.187 0.000 1.484 0.000 ve/lib/python3.8/site-packages/flake8/formatting/base.py:85(handle)
200032 0.296 0.000 1.443 0.000 ve/lib/python3.8/site-packages/flake8/checker.py:382(report)
100000 0.163 0.000 1.174 0.000 ve/lib/python3.8/site-packages/flake8/processor.py:225(build_logical_line)
200030 0.542 0.000 1.007 0.000 ve/lib/python3.8/site-packages/flake8/processor.py:280(noqa_line_for)
500010 0.616 0.000 0.999 0.000 ve/lib/python3.8/site-packages/pyflakes/checker.py:259(iter_child_nodes)
100000 0.753 0.000 0.952 0.000 ve/lib/python3.8/site-packages/flake8/processor.py:186(build_logical_line_tokens)
200032 0.082 0.000 0.928 0.000 ve/lib/python3.8/site-packages/flake8/formatting/base.py:189(write)
200032 0.205 0.000 0.846 0.000 ve/lib/python3.8/site-packages/flake8/formatting/base.py:182(_write)
40 0.003 0.000 0.787 0.020 ve/lib/python3.8/site-packages/flake8_isort.py:190(run)
3600000 0.758 0.000 0.779 0.000 ve/lib/python3.8/site-packages/flake8/processor.py:166(update_checker_state_for)
300000 0.269 0.000 0.670 0.000 ve/lib/python3.8/site-packages/pyflakes/checker.py:961(futuresAllowed)
100000 0.050 0.000 0.640 0.000 ve/lib/python3.8/site-packages/pyflakes/checker.py:2197(ARGUMENTS)
10 0.000 0.000 0.617 0.062 ve/lib/python3.8/site-packages/isort/api.py:137(sort_stream)
10 0.359 0.036 0.614 0.061 ve/lib/python3.8/site-packages/isort/core.py:29(process)
700000 0.452 0.000 0.556 0.000 ve/lib/python3.8/site-packages/flake8/processor.py:393(is_eol_token)
200032 0.201 0.000 0.514 0.000 ve/lib/python3.8/site-packages/flake8/statistics.py:30(record)
200010 0.443 0.000 0.467 0.000 ve/lib/python3.8/site-packages/pyflakes/checker.py:1347(_handle_type_comments)
200032 0.329 0.000 0.329 0.000 ve/lib/python3.8/site-packages/flake8/formatting/default.py:30(format)
99990 0.075 0.000 0.329 0.000 ve/lib/python3.8/site-packages/pyflakes/checker.py:1108(differentForks)
200032 0.148 0.000 0.276 0.000 ve/lib/python3.8/site-packages/flake8/style_guide.py:72(is_inline_ignored)
100000 0.104 0.000 0.270 0.000 ve/lib/python3.8/site-packages/pyflakes/checker.py:1494(handleAnnotation)
99990 0.097 0.000 0.263 0.000 ve/lib/python3.8/site-packages/pyflakes/checker.py:1058(report)
@dreid So IOW, it sounds like flake8
isn't smart enough to realize that no checks are enabled that would actually require it (or pyflakes) parsing the file...
Meanwhile, if you want something fast, you can use ruff
😄