Panels dialog saves a ready I/O port draft on close and keeps an unfinished one; one qualified message-name rule on both sides

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WgBfkm4rCmtd1T4vHWjEPx

backend/fluksio/flow/messages.py

@@ -12,6 +12,7 @@ from __future__ import annotations
 
 import json
 import math
+import re
 from enum import Enum
 from typing import Any
 
@@ -320,6 +321,24 @@ class MessageSpec(BaseModel):
         return hash((self.name, self.port))
 
 
+#: A message named with its flow: the flow's own name, then the name inside it.
+#: The one rule for anywhere a name has to arrive qualified; the frontend holds
+#: a copy (``QUALIFIED_MESSAGE`` in ``deriveEdges.ts``).
+QUALIFIED_PATTERN = re.compile(r"[a-z][a-z0-9_]*(\.[A-Za-z0-9_]+)+")
+
+QUALIFIED_RULE = (
+    "Name the message as flow.name: a lowercase flow name, a dot, "
+    "then letters, digits and underscores"
+)
+
+
+def validate_qualified(value: str) -> str:
+    """A qualified message name, or a ``ValueError`` saying what one looks like."""
+    if not QUALIFIED_PATTERN.fullmatch(value):
+        raise ValueError(QUALIFIED_RULE)
+    return value
+
+
 def qualify(flow: str, name: str) -> str:
     """Resolve a message name against its flow namespace."""
     if not name:

backend/fluksio/flow/panels.py

@@ -21,6 +21,7 @@ from pydantic import BaseModel, Field, field_validator
 
 from fluksio.core.config import settings
 from fluksio.flow.dashboards import DashboardDef, DashboardNotFound, DashboardStore
+from fluksio.flow.messages import validate_qualified
 from fluksio.flow.schemas import _validate_name
 
 #: Free text the device interprets: ``gpio.4``, ``backlight``, ``mic``.
@@ -51,14 +52,7 @@ class PanelPort(BaseModel):
             raise ValueError("Use lowercase letters, digits, underscores and dots")
         return value
 
-    @field_validator("message")
-    @classmethod
-    def _check_message(cls, value: str) -> str:
-        flow, _, name = value.partition(".")
-        if not name:
-            raise ValueError("Name the message with its flow, as flow.name")
-        _validate_name(flow)
-        return value
+    _check_message = field_validator("message")(validate_qualified)
 
 
 class PanelDef(BaseModel):

backend/tests/flow/test_messages.py

@@ -2,7 +2,13 @@ import json
 
 import pytest
 
-from fluksio.flow.messages import DType, MessageSpec, flow_of, qualify
+from fluksio.flow.messages import (
+    DType,
+    MessageSpec,
+    flow_of,
+    qualify,
+    validate_qualified,
+)
 
 
 def test_port_defaults_to_last_name_segment():
@@ -201,3 +207,14 @@ def test_a_value_that_refers_to_itself_does_not_hang_the_check():
     loop: dict = {}
     loop["self"] = loop
     spec.check(loop)
+
+
+@pytest.mark.parametrize("name", ["home.doorbell", "house.kitchen.temperature"])
+def test_a_qualified_name_names_its_flow(name):
+    assert validate_qualified(name) == name
+
+
+@pytest.mark.parametrize("name", ["doorbell", "Home.x", "home.", "home.a-b", "home..x"])
+def test_anything_else_is_refused_with_the_rule(name):
+    with pytest.raises(ValueError, match="flow.name"):
+        validate_qualified(name)