feat: scoped host merge for non-admin config saves

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NfPpSpccTWBfZg1FTveyaU

tests/test_config_access.py

@@ -56,3 +56,137 @@ TCS = {
 def test_user_threshold_configs_global_plus_own():
     assert set(ca.user_threshold_configs(TCS, "alice")) == {"default", "alice_tc"}
     assert set(ca.user_threshold_configs(TCS, "bob")) == {"default"}
+
+
+# ---------------------------------------------------------------------------
+# merge_hosts_scoped
+# ---------------------------------------------------------------------------
+
+MERGE_HOSTS = {
+    "mine": {"owner": "alice", "watch": True, "notification_channels": ["global_ch"]},
+    "managed": {"owner": "bob", "managers": ["alice"], "watch": True,
+                "notification_channels": ["bob_ch"]},
+    "foreign": {"owner": "bob", "watch": False},
+}
+MERGE_CHANNELS = {
+    "global_ch": {"type": "pushover"},
+    "alice_ch": {"type": "email", "owner": "alice"},
+    "bob_ch": {"type": "signal", "owner": "bob"},
+}
+MERGE_TCS = {"alice_tc": {"owner": "alice"}, "bob_tc": {"owner": "bob"}}
+
+
+def _merge_hosts(payload, existing=None):
+    return ca.merge_hosts_scoped(
+        existing if existing is not None else dict(MERGE_HOSTS),
+        payload, "alice", MERGE_CHANNELS, MERGE_TCS,
+    )
+
+
+def _full_payload(**overrides):
+    """Payload covering alice's full visible subset, with per-host overrides."""
+    p = {
+        "mine": {"owner": "alice", "watch": True, "notification_channels": ["global_ch"]},
+        "managed": {"watch": True, "notification_channels": ["bob_ch"]},
+    }
+    p.update(overrides)
+    return p
+
+
+def test_merge_hosts_preserves_foreign_hosts():
+    result = _merge_hosts(_full_payload())
+    assert result["foreign"] == {"owner": "bob", "watch": False}
+
+
+def test_merge_hosts_manager_edits_settings():
+    result = _merge_hosts(_full_payload(managed={"watch": False, "dyndns": True,
+                                                 "notification_channels": ["bob_ch"]}))
+    assert result["managed"]["watch"] is False
+    assert result["managed"]["dyndns"] is True
+    # access fields carried over untouched
+    assert result["managed"]["owner"] == "bob"
+    assert result["managed"]["managers"] == ["alice"]
+
+
+def test_merge_hosts_manager_cannot_change_owner():
+    with pytest.raises(ca.ScopedMergeError, match="managed"):
+        _merge_hosts(_full_payload(managed={"watch": True, "owner": "alice"}))
+
+
+def test_merge_hosts_manager_cannot_change_managers():
+    with pytest.raises(ca.ScopedMergeError, match="managers"):
+        _merge_hosts(_full_payload(managed={"watch": True, "managers": ["alice", "carol"]}))
+
+
+def test_merge_hosts_manager_same_access_values_ok():
+    # Submitting unchanged access fields is not a violation.
+    result = _merge_hosts(_full_payload(managed={"watch": True, "owner": "bob",
+                                                 "managers": ["alice"],
+                                                 "notification_channels": ["bob_ch"]}))
+    assert result["managed"]["owner"] == "bob"
+
+
+def test_merge_hosts_manager_cannot_delete():
+    payload = {"mine": {"owner": "alice", "watch": True}}  # 'managed' missing
+    with pytest.raises(ca.ScopedMergeError, match="managed"):
+        _merge_hosts(payload)
+
+
+def test_merge_hosts_owner_can_delete():
+    payload = _full_payload()
+    del payload["mine"]
+    result = _merge_hosts(payload)
+    assert "mine" not in result
+    assert "managed" in result and "foreign" in result
+
+
+def test_merge_hosts_owner_can_transfer_ownership():
+    result = _merge_hosts(_full_payload(mine={"owner": "bob", "watch": True}))
+    assert result["mine"]["owner"] == "bob"
+
+
+def test_merge_hosts_new_host_owner_forced():
+    result = _merge_hosts(_full_payload(newhost={"watch": True, "owner": "bob"}))
+    assert result["newhost"]["owner"] == "alice"
+
+
+def test_merge_hosts_cannot_touch_foreign_host():
+    with pytest.raises(ca.ScopedMergeError, match="foreign"):
+        _merge_hosts(_full_payload(foreign={"watch": True}))
+
+
+def test_merge_hosts_cannot_add_foreign_private_channel():
+    with pytest.raises(ca.ScopedMergeError, match="bob_ch"):
+        _merge_hosts(_full_payload(mine={"owner": "alice", "watch": True,
+                                         "notification_channels": ["bob_ch"]}))
+
+
+def test_merge_hosts_keeps_preexisting_foreign_assignment():
+    # 'managed' already has bob_ch; keeping it is fine.
+    result = _merge_hosts(_full_payload())
+    assert result["managed"]["notification_channels"] == ["bob_ch"]
+
+
+def test_merge_hosts_can_add_global_and_own_channel():
+    result = _merge_hosts(_full_payload(mine={"owner": "alice", "watch": True,
+                                              "notification_channels": ["global_ch", "alice_ch"]}))
+    assert result["mine"]["notification_channels"] == ["global_ch", "alice_ch"]
+
+
+def test_merge_hosts_threshold_assignment_validated():
+    with pytest.raises(ca.ScopedMergeError, match="bob_tc"):
+        _merge_hosts(_full_payload(mine={"owner": "alice", "watch": True,
+                                         "threshold_config": ["bob_tc"]}))
+    result = _merge_hosts(_full_payload(mine={"owner": "alice", "watch": True,
+                                              "threshold_config": ["default", "alice_tc"]}))
+    assert result["mine"]["threshold_config"] == ["default", "alice_tc"]
+
+
+def test_merge_hosts_rejects_unknown_fields():
+    with pytest.raises(ca.ScopedMergeError, match="sneaky"):
+        _merge_hosts(_full_payload(mine={"owner": "alice", "watch": True, "sneaky": 1}))
+
+
+def test_merge_hosts_owner_clearing_list_removes_key():
+    result = _merge_hosts(_full_payload(mine={"owner": "alice", "watch": True}))
+    assert "notification_channels" not in result["mine"]