Match CPython's "field 'X' is required for Y" error format when
required scalar AST fields receive None during ast_from_object
conversion. Previously these produced TypeError or a generic
"None disallowed in expression list" ValueError.
Fields covered (Alias.name, Arg.arg, Comprehension.target/iter,
Keyword.value, MatchCase.pattern, WithItem.context_expr,
YieldFrom.value): all now raise the CPython-compatible message
verbatim.
Add a get_node_field_required helper alongside the existing
get_node_field / get_node_field_opt and switch the eight call
sites that read these required scalar fields. The helper rejects
None with the proper ValueError before the value flows into the
type converter where Rust's strong typing would otherwise force a
generic catch-all error. Optional fields (read via
get_node_field_opt) and fields where None is valid (e.g.
Constant.value) are unaffected.
This complements the existing AST validator pass at
crates/vm/src/stdlib/_ast/validate.rs (hooked at _ast.rs:763):
the validator handles post-conversion semantic invariants
(ExprContext, empty body, cross-field rules) but cannot handle
required-scalar-field None because Rust's non-Option types reject
None at conversion time, before validation runs.
Verified byte-identical with CPython 3.14.4 for all seven probe
cases. test.test_ast.test_ast: 227 tests, expected failures
38 -> 36 (test_empty_yield_from and test_none_checks unmasked,
no regressions). test.test_compile: 0 regressions.
This directory contains all of the Python files that make up the standard
library for RustPython.
Most of these files are copied over from the CPython repository (the 3.7
branch), with slight modifications to allow them to work under RustPython. The
current goal is to complete the standard library with as few modifications as
possible. Current modifications are just temporary workarounds for bugs/missing
feature within the RustPython implementation.
The first big module we are targeting is unittest, so we can leverage the
CPython test suite.
Changjoon
aa04f8db24