fix(disksage): accept readiness schema v4

backend/scripts/disksage_copy_readiness_handoff.py

@@ -355,7 +355,7 @@ def _decode_protocol(result: VerifierResult) -> dict[str, object]:
             and payload.get("ok") is True
             and payload.get("schema_kind") == "disksage.naruon.cloud-copy-readiness"
             and type(payload.get("schema_version")) is int
-            and payload.get("schema_version") == 3
+            and payload.get("schema_version") in (3, 4)
             and payload.get("provider") in PROVIDERS
             and payload.get("readiness_state") in READINESS_STATES
             and type(payload.get("candidate_count")) is int

backend/tests/test_disksage_copy_readiness_handoff.py

@@ -25,7 +25,7 @@ def _success_payload() -> dict[str, object]:
     return {
         "ok": True,
         "schema_kind": "disksage.naruon.cloud-copy-readiness",
-        "schema_version": 3,
+        "schema_version": 4,
         "provider": "icloud",
         "readiness_state": "blocked",
         "candidate_count": 19,
@@ -111,6 +111,19 @@ def test_main_delegates_to_absolute_verifier_without_shell_env_or_input_read(
     assert not (tmp_path / "must-not-exist").exists()
 
 
+@pytest.mark.parametrize("schema_version", [3, 4])
+def test_protocol_decoder_accepts_supported_schema_versions(schema_version):
+    """Accept the deployed v3 contract and the WAL-consistent v4 contract."""
+    payload = {**_success_payload(), "schema_version": schema_version}
+    result = handoff.VerifierResult(
+        0,
+        json.dumps(payload).encode("utf-8"),
+        b"",
+    )
+
+    assert handoff._decode_protocol(result) == payload
+
+
 @pytest.mark.parametrize("exit_code", [64, 65])
 def test_main_preserves_valid_disksage_failure_protocol(tmp_path, capsys, exit_code):
     payload = {
@@ -711,6 +724,7 @@ def wrapped_popen(*args, **kwargs):
     ("payload", "exit_code"),
     [
         ({**_success_payload(), "private_path": "/private/source"}, 0),
+        ({**_success_payload(), "schema_version": 5}, 0),
         ({"ok": False, "error_code": "invalid"}, 0),
         (_success_payload(), 65),
         ({"ok": False, "error_code": "invalid/path"}, 65),

docs/integrations/disksage-readiness-version-policy.md

@@ -0,0 +1,18 @@
+# DiskSage readiness schema compatibility
+
+Naruon delegates validation of DiskSage cloud-copy readiness artifacts to the digest-bound offline Rust verifier and then validates the verifier's bounded JSON response.
+
+## Supported versions
+
+Naruon accepts exactly these successful response versions:
+
+- **Schema 3** — the deployed readiness contract used before WAL-consistency evidence was added.
+- **Schema 4** — the WAL-consistent readiness contract.
+
+Supporting version 4 is an additive compatibility change. Version 3 remains valid so an independently deployed DiskSage installation does not fail merely because Naruon upgrades first. Versions outside this explicit set are rejected.
+
+## Invariants shared by both versions
+
+A successful response must retain the exact allowlisted fields, a recognized provider and readiness state, non-negative candidate counts and byte totals, a lowercase SHA-256 fingerprint, and false values for every local-path, raw-metadata, cloud-write, and source-eviction claim. Duplicate JSON member names, unexpected stderr, oversized output, invalid encodings, unknown fields, or unsupported exit codes fail closed.
+
+The compatibility policy changes only the accepted schema-version set. It does not authorize a cloud write, source eviction, network request, or access to local file paths.