reduce "python_3000_invalid_escape_sequence" execution time by ~60% #1293
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Closed
abebus
changed the title
abebus
changed the title
asottile
force-pushed
the
speedups/python_3000_invalid_escape_sequence
branch
from
a315899 to
f9301e4
Compare
Zaczero
reviewed
Aug 5, 2025
Comment on lines
-1664
to
+1669
| if token_type in {tokenize.STRING, FSTRING_START, TSTRING_START}: | ||
| if ( | ||
| token_type == tokenize.STRING or | ||
| token_type == FSTRING_START or | ||
| token_type == TSTRING_START | ||
| ): |
There was a problem hiding this comment.
I am watching your stream VOD and I simply wanted to let you know that the reason the previous solution was very slow is that Python LOAD_CONST optimization applies only to trivial Python objects (with guaranteed no side effects). tokenize.STRING may have side effects, which prevents this optimization and makes Python construct the set each time you access it in a conditional. My typical workaround for such performance-oriented cases, without polluting the global scope with lots of sets/dicts, is to simply put them in kwargs of the function that run just once. See this bytecode: https://godbolt.org/z/qoPdYvha3
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Benchmarks