fix(storage): an absent source tier refuses nothing

polylogue/storage/raw_retention.py

@@ -1306,6 +1306,11 @@ def raw_frontier_blocked_source_paths(
 ) -> RawFrontierBlockedPaths:
     """Attribute the frontier proof's refusals to exact source paths."""
 
+    if not (archive_root / "source.db").is_file():
+        # No source tier means nothing has been acquired yet, so there is
+        # nothing to select and nothing to refuse. An unreadable tier still
+        # refuses below: absence and damage are different states.
+        return RawFrontierBlockedPaths(frozenset(), None)
     projection = raw_frontier_integrity_projection(
         archive_root,
         raw_materialization_readiness,

tests/unit/maintenance/test_archive_verification.py

@@ -1419,12 +1419,20 @@ def test_blob_refs_liveness_passes_on_coherent_archive(tmp_path: Path) -> None:
 
 
 def test_blob_reference_closure_rejects_acquired_attachment_without_ref(tmp_path: Path) -> None:
+    """An acquired attachment whose refs vanished is archive debt.
+
+    ``ref_count`` is the discriminator: a non-zero count with no surviving
+    ``attachment_refs`` row means the sweep lost edges it once had, while a
+    zero count is an attachment that never had one.
+
+    Anti-vacuity: seeding ``ref_count`` 0 instead describes the explained
+    shape and the check stays clean."""
     _seed_coherent_archive(tmp_path)
     conn = _connect(tmp_path / "index.db")
     try:
         conn.execute(
             "INSERT INTO attachments (attachment_id, byte_count, blob_hash, acquisition_status, ref_count) "
-            "VALUES ('orphan-acquired', 1, ?, 'acquired', 0)",
+            "VALUES ('orphan-acquired', 1, ?, 'acquired', 1)",
             (b"a" * 32,),
         )
         conn.commit()

tests/unit/storage/test_raw_retention.py

@@ -2577,6 +2577,23 @@ def test_deferred_cursor_never_blocks_source_selection(tmp_path: Path) -> None:
     assert raw_frontier_source_selection_block_reason(tmp_path) is None
 
 
+def test_absent_source_tier_refuses_nothing(tmp_path: Path) -> None:
+    """An archive root with no source tier has nothing to select or refuse.
+
+    Anti-vacuity: dropping the absence branch makes the projection report
+    the tier unavailable under both the broken-head and cursor checks, and
+    those reasons surface as an unattributed refusal that blocks the whole
+    materialization pass on a freshly created archive.
+    """
+    archive_root = tmp_path / "archive"
+    archive_root.mkdir()
+
+    blocked = raw_retention_mod.raw_frontier_blocked_source_paths(archive_root, {})
+
+    assert blocked.unattributed_reason is None
+    assert blocked.source_paths == frozenset()
+
+
 def test_blocked_source_paths_refuse_violations_and_admit_authority_gaps(tmp_path: Path) -> None:
     """A violation names the path it refuses; a gap names a path only processing can resolve.