fix: clarify pending admission failure outcome (#101)

src/fenris/collector.py

@@ -428,10 +428,15 @@ def _is_store_or_invariant_failure(exc: Exception) -> bool:
     ) or isinstance(exc, InvariantViolationError)
 
 
-def _pending_capacity_error(reason: str) -> RuntimeError:
+def _pending_capacity_error(
+    reason: str,
+    *,
+    acquisition_skipped: bool = False,
+) -> RuntimeError:
+    outcome = "; no new observation acquired" if acquisition_skipped else ""
     return RuntimeError(
         "pending publication capacity full "
-        f"({PENDING_PUBLICATION_LIMIT} observations); no new observation acquired; "
+        f"({PENDING_PUBLICATION_LIMIT} observations){outcome}; "
         f"{reason}"
     )
 
@@ -469,12 +474,16 @@ def _recover_pending_for_admission(conn: sqlite3.Connection) -> int:
             raise failure.cause
         if pending_count >= PENDING_PUBLICATION_LIMIT:
             raise _pending_capacity_error(
-                f"recovery failed: {failure.cause}"
+                f"recovery failed: {failure.cause}",
+                acquisition_skipped=True,
             ) from failure.cause
         return failure.published_count
 
     if _pending_count(conn) >= PENDING_PUBLICATION_LIMIT:
-        raise _pending_capacity_error("recovery left the queue full")
+        raise _pending_capacity_error(
+            "recovery left the queue full",
+            acquisition_skipped=True,
+        )
     return recovered