What was the problem/requirement? (What/Why)

Conformance fixtures 2.15--list-bool-param-{interpolation,runtime} (added by OpenJobDescription/openjd-specifications#158) pass on openjd-rs but fail on the Python CLI with List contains incompatible types: bool, string.

Template Schemas §2.15 states each LIST[BOOL] item accepts the same values as scalar BOOL: bool literals, int/float 0/1, and the case-insensitive strings true/yes/on/1 and false/no/off/0. The Python model validated those spellings at decode time but stored the list verbatim, so a heterogeneous list reached the expression engine un-normalized. Homogeneous non-bool spellings (e.g. ["yes","off"], [1,0]) were worse: silently accepted as the wrong list type (ListString/ListInt), failing only when a boolean operator touched an element.

What was the solution? (How)

Coerce each LIST[BOOL] item to a canonical bool at the job-creation boundary (_create_job.py only; template models are not mutated):

YAML template
   |  decode (pydantic validates spellings, stores them verbatim; unchanged)
   v
Template object    default = ["yes", 0, True]    <- keeps the author's spellings (pinned by test)
   |
   |  create_job()  * conversion happens at this gate
   v
Job object         value = [True, False, True]   <- every reader sees canonical bools
   |
   v
Expression engine / sessions / cli               <- untouched, fixed for free

• template defaults: _collect_defaults_2023_09
• submitted values: _coerce_expr_param_value, both native lists and JSON strings (the shared LIST JSON parse is unchanged for other list types)
• gated exactly on LIST_BOOL; invalid items keep Parameter <name>: context

The coercion reuses _coerce_bool_value, the same function the scalar BOOL type and the decode-time item validation use, so the accepted value set cannot drift between the scalar and list types.

Why convert at job creation, not at template decode (where openjd-rs converts): the difference is where the conversion can live. In Rust it lives in the type system: BoolValue deserializes "yes" straight into a bool, so an un-normalized value is unrepresentable. In pydantic it would live in validators, and validators can be bypassed: environment-template merges go through model_copy, which skips them, so decode-time normalization leaks that path and the job-creation coercion is needed anyway. One site instead of two. It also keeps decoded templates round-tripping the author's spellings, a long-released behavior. Both implementations converge where conformance observes them: the created Job's values.

LIST[FLOAT] integer items are intentionally not normalized: §2.14 enumerates no alternate spellings, no fixture pins it, and the expression engine promotes int to float. Noting it here rather than changing it silently.

What was the impact?

Created-Job LIST[BOOL] values are now canonical booleans. A previously-working homogeneous ["yes","no"] now stores and interpolates as true/false, matching openjd-rs. Audited openjd-sessions, openjd-cli, and downstream consumers: none read the raw spellings.

Template objects are unchanged: a decoded template's default keeps the author's original spellings.

Testing

• 31 new unit tests: mixed/homogeneous/mixed-case spellings, native and JSON submitted values, adversarial items via both the JSON and native-list paths ([[true]], [null], [2], [2.0], non-list JSON), empty list, environment-template merged defaults, Parameter <name>: context on per-item failures (JSON-level errors stay verbatim like other list types), template-object non-mutation and dump round-trip, default=None guard, and non-BOOL list guards (LIST[INT] JSON parsing, LIST[STRING]/LIST[PATH]/LIST[LIST[INT]] passthrough). Full suite: 5648 passed; ruff/black/mypy clean.
• Conformance A/B (run_openjd_cli_tests.py, full 2023-09 suite, released 0.11.6 vs this change): 1172 passed / 2 failed → 1174 passed / 0 failed. The only delta is the two 2.15 list-bool fixtures flipping to pass:

240,241c240,241
<   ✗ 2.15--list-bool-param-interpolation
<   ✗ 2.15--list-bool-param-runtime
---
>   ✓ 2.15--list-bool-param-interpolation
>   ✓ 2.15--list-bool-param-runtime

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