fix: CoPilot review round-3 pass on PR #45

- harness/prompt_management.py: fix misleading comment on
  FixtureExpectedRaises.carries (secondary_backend_call_count is
  a sibling field on FixtureExpectedPerCall, not inside carries).
- manager.py: replace 'assert causes' with an explicit
  'if not causes: raise RuntimeError(...)' guard so the
  invariant holds under 'python -O' (asserts stripped) and
  surfaces as a clear RuntimeError rather than an opaque
  IndexError if a future change ever silently swallows an
  exception in the fallback loop.
- test_prompts.py: rewrite the active-prompt-in-nested-async-function
  test to spawn via asyncio.create_task so it actually exercises
  context-copy across the task boundary, matching the function
  name's implied claim. The previous form's await ran in the same
  context where ContextVar propagation is trivially expected.

Author: chris-colinsky

src/openarmature/prompts/manager.py

@@ -81,7 +81,19 @@ async def fetch(self, name: str, label: str = "production") -> Prompt:
                     label,
                 )
                 continue
-        assert causes
+        if not causes:
+            # Unreachable under current control flow: the constructor
+            # guarantees ``len(self._backends) >= 1`` and the only
+            # fall-through path from the for-loop appends to
+            # ``causes``. Explicit guard rather than ``assert`` so
+            # the invariant holds under ``python -O`` (asserts get
+            # stripped) — a future change that silently swallowed an
+            # exception in the loop would surface here as a clear
+            # RuntimeError instead of an opaque IndexError on the
+            # next line.
+            raise RuntimeError(
+                "PromptManager.fetch internal invariant violated: no backends consulted but loop exhausted"
+            )
         raise PromptStoreUnavailable(
             f"all prompt backends unavailable for ({name!r}, {label!r})",
             name=name,

tests/conformance/harness/prompt_management.py

@@ -72,10 +72,12 @@ class BackendTarget(_StrictModel):
 
 class FixtureExpectedRaises(_PermissiveModel):
     category: str
-    # Optional extra carries — fixture 005 uses ``description_mentions``,
-    # ``name``, ``version``, ``label``. fixture 008 uses
-    # ``secondary_backend_call_count``. Permissive on this shape so
-    # fixtures evolve.
+    # Optional extra carries. Fixture 005 surfaces
+    # ``description_mentions`` / ``name`` / ``version`` / ``label``
+    # here. Permissive on this shape so fixtures evolve;
+    # per-backend call-count assertions live on the parent
+    # ``FixtureExpectedPerCall`` (see ``secondary_backend_call_count``
+    # and ``backend_call_counts`` below), not in ``carries``.
     carries: dict[str, Any] | None = None
 
 

tests/unit/test_prompts.py

@@ -354,7 +354,8 @@ async def _read_in_task() -> PromptResult | None:
         return current_prompt_result()
 
     with with_active_prompt(pr):
-        result = await _read_in_task()
+        task = asyncio.create_task(_read_in_task())
+        result = await task
     assert result is pr