move ICON_MAX_LENGTH to esphome/core/config.py alongside other max length constants

esphome/config_validation.py

@@ -398,13 +398,10 @@ def string_strict(value):
     )
 
 
-# Max icon string length (63 chars + null = 64-byte PROGMEM buffer)
-# Keep in sync with MAX_ICON_LENGTH in esphome/core/entity_base.h
-ICON_MAX_LENGTH = 63
-
-
 def icon(value):
     """Validate that a given config value is a valid icon."""
+    from esphome.core.config import ICON_MAX_LENGTH
+
     value = string_strict(value)
     if not value:
         return value

esphome/core/config.py

@@ -188,6 +188,10 @@ else:
 # Keep in sync with ESPHOME_FRIENDLY_NAME_MAX_LEN in esphome/core/entity_base.h
 FRIENDLY_NAME_MAX_LEN = 120
 
+# Max icon string length (63 chars + null = 64-byte PROGMEM buffer)
+# Keep in sync with MAX_ICON_LENGTH in esphome/core/entity_base.h
+ICON_MAX_LENGTH = 63
+
 AREA_SCHEMA = cv.Schema(
     {
         cv.GenerateID(CONF_ID): cv.declare_id(Area),

esphome/core/entity_helpers.py

@@ -17,6 +17,7 @@ from esphome.const import (
     CONF_UNIT_OF_MEASUREMENT,
 )
 from esphome.core import CORE, ID, CoroPriority, coroutine_with_priority
+from esphome.core.config import ICON_MAX_LENGTH
 from esphome.cpp_generator import MockObj, RawStatement, add, get_variable
 import esphome.final_validate as fv
 from esphome.helpers import cpp_string_escape, fnv1_hash_object_id, sanitize, snake_case
@@ -190,9 +191,9 @@ def register_unit_of_measurement(value: str) -> int:
 
 def register_icon(value: str) -> int:
     """Register an icon string and return its 1-based index."""
-    if value and len(value) > cv.ICON_MAX_LENGTH:
+    if value and len(value) > ICON_MAX_LENGTH:
         raise ValueError(
-            f"Icon string too long ({len(value)} chars, max {cv.ICON_MAX_LENGTH}): '{value}'"
+            f"Icon string too long ({len(value)} chars, max {ICON_MAX_LENGTH}): '{value}'"
         )
     return _register_string(value, _get_pool().icons, _MAX_ICONS, "icon")