fix: add dataclass-aware YAML field type validation at parse time#192
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YAML values with unquoted colons silently parse as dicts instead of strings, causing opaque TypeError from protobuf C code at push time. Uses dataclasses.fields() + typing.get_type_hints() to automatically validate str and list[str] fields in YamlResource.read_local_resource, with recursion into nested dataclass fields. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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A list[str] field receiving a dict (e.g., prompt_assertions parsed as a mapping) would iterate dict keys as strings, silently passing the check. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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- Check all scalar types (str, int, float, bool) not just str - Validate dict[K, V] keys and values when K/V are scalar types - Accept int where float is expected (YAML parses 500 as int) - Reject bool where int/float is expected (yes/no auto-cast) - Validate list[str] field is actually a list, not a dict - Remove verbose YAML hint from error messages Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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oeisenberg
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Jun 17, 2026
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Summary
Adds automatic type validation for YAML resource fields at parse time, catching the colon-space footgun where unquoted strings silently parse as dicts.
Motivation
YAML values with unquoted mid-sentence colons (e.g.,
the outcome: either a time slot or...) silently parse as dicts instead of strings. This causes opaqueTypeError: bad argument type for built-in operationfrom protobuf C code at push time — with no hint about which field or file caused it. A confirmed case inprompt_assertionsburned ~7 push attempts before the user found the cause.Supersedes #191 — moves the detection from
project.py's generic error handler down to the YAML resource layer with field-level precision.Changes
check_yaml_field_types()inresource.pyusingdataclasses.fields()+typing.get_type_hints()to introspect declared types and validatestr/list[str]fields aren't dictsTestCaseAssertion.promptsinsideTestCase)YamlResource.read_local_resource— all YAML resources get the check automaticallyFlowStepandPronunciationoverridingread_local_resourcemethodsTest strategy
poly <command>)Checklist
ruff check .andruff format --check .passpytestpassespolyCLI interface (or migration path documented)Screenshots / Logs
Example error output for the confirmed bug (test case with unquoted colon in prompt assertion):
🤖 Generated with Claude Code