fix: handle list[dict] variable values in BuildVariable hash

[gaetan-h]

Summary

cdf modules list (and any command that calls compare_modules()) crashes with:

TypeError: unhashable type: 'dict'
  File "_module_resources.py", line 163, in compare_modules
    if set(current_module_variables) != set(cached_module.build_variables):

when a config variable has a list-of-dicts value — for example:

variables:
  modules:
    site_readiness:
      - site_name_lower: clov
        site_name_upper: CLOV
        site_prefix: CLV
      - site_name_lower: egina
        site_name_upper: EGINA
        site_prefix: EGI

Root Cause

BuildVariable is a frozen dataclass, so Python auto-generates __hash__ from all fields including value. Both load_raw() and load() converted list values with tuple(value), but if the list contains dicts, those dicts end up inside the tuple and are still unhashable — causing set() to fail.

Fix

Extract a _to_hashable() helper that recursively converts lists and dicts to nested tuples of sorted key-value pairs:

def _to_hashable(v: Any) -> Any:
    if isinstance(v, list):
        return tuple(_to_hashable(i) for i in v)
    if isinstance(v, dict):
        return tuple(sorted((k, _to_hashable(val)) for k, val in v.items()))
    return v

Applied in both:

• load_raw() — live variables parsed from config.*.yaml
• BuildVariable.load() — variables read back from build_info.*.yaml cache

Tests

Two new test cases in test_build_variables.py:

• test_load_raw_list_of_dicts_is_hashable — verifies load_raw() with a list[dict] variable produces a hashable BuildVariable
• test_load_from_cache_list_of_dicts_is_hashable — verifies BuildVariable.load() (cache read path) does the same

All 10 existing + new tests pass.

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