Python: CSV Sniffer Gets Untangled From Exponential Time
Serhiy Storchaka landed and backported fixes for two separate performance blowups in the CSV Sniffer, one exponential and one quadratic, spreading the corrected regular expressions across every supported branch from 3.10 through 3.15. A quieter but steady stream of platform and packaging fixes for Android, Windows, and site-packages rounded out the day.
Duration: PT2M30S
Episode overview
This episode is a short developer briefing from Python.
It explains recent repository work in plain language.
- Show: Python
- Published: 2026-08-03T13:06:54Z
- Audio duration: PT2M30S
Transcript excerpt
This excerpt keeps the crawler page concise. Listen to the episode or use the RSS feed for the full update.
Good day, and welcome to Python for August 3rd, 2026.
The clearest story in today's activity is a performance fire drill in the standard library's CSV module. Serhiy Storchaka identified that csv.Sniffer's pattern matching for doubled quotes could blow up to exponential time on adversarial input, and separately, that quoted-field detection was scaling quadratically. PR…
A second theme is small-but-real API and behavior corrections. BHUVANSH855's docstring fix for decimal.Context.copy, backported across 3.14 and 3.15, corrects documentation that claimed flags get cleared on copy when they don't — a subtle trap for anyone relying on the docs. Separately, PR 155104 addresses a sharper…
Platform and build work continued in parallel — the Android python3.pc linking fix (PR 144776) is now backported to 3.13, 3.14, and 3.15, and Windows Tcl/Tk was updated to 9.0.4. Outside the CSV work, keep an eye on PR 155089, which proposes adding a ternary operator and a dollar-sign None-declaration syntax to the…
That's the briefing for August 3rd. Build carefully, and watch those regular expressions.
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