Python Bytes #459 Inverted dependency trees
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Nov 24, 2025 Discover the new frozendict built-in type introduced in PEP 814, enhancing Python's immutability. Dive into the transition from Material for MkDocs to the Rust-based Zensical project. Learn how Tack visualizes internal code dependencies and generates architecture graphs. Exciting speedups are on the way for Python 3.15 and 3.16, with enhancements like 30% faster decompression. Plus, find out how to use pip tools to analyze inverted dependency trees and enjoy some witty banter about cloud outages!
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Builtin Immutable Mapping
- frozendict adds a builtin immutable mapping type to Python to prevent unintended modifications and improve safety.
- Michael Kennedy highlights frozen types help express intent and enable safer concurrent reads without locks.
Prefer Immutable Data For Thread Safety
- Use immutable data like frozendict when multiple threads only need read access to avoid locking overhead.
- Michael Kennedy advises preferring frozen types to achieve thread-safe reads and deterministic behavior.
Existing Frozen Types Matter
- Python already has many immutable types like tuple, frozenset, and frozen dataclasses that inform design and safety choices.
- Michael Kennedy notes frozen dict fills a gap and may encourage more immutable patterns in future Python versions.
