4: Make visitor immutable friendly#253
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Cito merged 4 commits intographql-python:mainfrom Jan 8, 2026
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Introduce benchmarks using a large (~117KB) GraphQL query to measure parse and pickle serialization performance. These provide a baseline for comparing serialization approaches in subsequent commits. Baseline performance (measrued on a Macbook Pro M4 Max): - Parse: 81ms - Pickle encode: 24ms - Pickle decode: 42ms - Roundtrip: 71ms
Prepares AST for immutability by using tuples instead of lists for collection fields. This aligns with the JavaScript GraphQL library which uses readonly arrays, and enables future frozen datastructures.
Python 3.9 reaches end-of-life October 2025. Python 3.10 adoption is now mainstream - major frameworks (strawberry, Django 5.0, FastAPI) require it. This enables modern Python features: - Dataclasses with `kw_only` - Union types with `|` syntax (PEP 604) - isinstance() with union types directly - match statements for pattern matching
Modifies the AST visitor to use copy-on-write semantics when applying edits. Instead of mutating nodes in place, the visitor now creates new node instances with the edited values. This prepares for frozen AST nodes while maintaining backwards compatibility. The visitor accumulates edits and applies them by constructing new nodes, enabling the transition to immutable data structures.
Merging this PR will not alter performanceSummary
Performance Changes
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Cito
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Jan 8, 2026
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Modifies the AST visitor to use copy-on-write semantics when applying
edits. Instead of mutating nodes in place, the visitor now creates new
node instances with the edited values. This prepares for frozen AST
nodes while maintaining backwards compatibility.
The visitor accumulates edits and applies them by constructing new
nodes, enabling the transition to immutable data structures.