docs(mm): add reminder for self for field migrations

Author: psychedelicious

invokeai/app/services/shared/sqlite_migrator/migrations/migration_22.py

@@ -2,7 +2,7 @@
 import sqlite3
 from logging import Logger
 from pathlib import Path
-from typing import NamedTuple
+from typing import Any, NamedTuple
 
 from pydantic import ValidationError
 
@@ -29,8 +29,9 @@ def __call__(self, cursor: sqlite3.Cursor) -> None:
 
         for model_id, config_json in rows:
             try:
+                migrated_config_dict = self._migrate_config(config_json)
                 # Get the model config as a pydantic object
-                config = AnyModelConfigValidator.validate_json(config_json)
+                config = AnyModelConfigValidator.validate_python(migrated_config_dict)
             except ValidationError:
                 # This could happen if the config schema changed in a way that makes old configs invalid. Unlikely
                 # for users, more likely for devs testing out migration paths.
@@ -76,6 +77,26 @@ def __call__(self, cursor: sqlite3.Cursor) -> None:
 
         self._prune_empty_directories()
 
+    def _migrate_config(self, config_json: Any) -> str | None:
+        config_dict = json.loads(config_json)
+
+        # TODO: migrate fields, review changes to ensure we hit all cases for v6.7.0 to v6.8.0 upgrade.
+
+        # Prior to v6.8.0, we used an awkward combination of `config_path` and `variant` to distinguish between FLUX
+        # variants.
+        #
+        # `config_path` was set to one of:
+        #  - flux-dev
+        #  - flux-dev-fill
+        #  - flux-schnell
+        #
+        # `variant` was set to ModelVariantType.Inpaint for FLUX Fill models and ModelVariantType.Normal for all other FLUX
+        # models.
+        #
+        # We now use the `variant` field to directly represent the FLUX variant type, and `config_path` is no longer used.
+
+        return config_dict
+
     def _normalize_model_storage(self, key: str, path_value: str) -> NormalizeResult:
         models_dir = self._models_dir
         stored_path = Path(path_value)

invokeai/backend/model_manager/configs/main.py

@@ -264,18 +264,6 @@ class Main_Checkpoint_FLUX_Config(Checkpoint_Config_Base, Main_Config_Base, Conf
     base: Literal[BaseModelType.Flux] = Field(default=BaseModelType.Flux)
 
     variant: FluxVariantType = Field()
-    # Prior to v6.8.0, we used an awkward combination of `config_path` and `variant` to distinguish between FLUX
-    # variants.
-    #
-    # `config_path` was set to one of:
-    #  - flux-dev
-    #  - flux-dev-fill
-    #  - flux-schnell
-    #
-    # `variant` was set to ModelVariantType.Inpaint for FLUX Fill models and ModelVariantType.Normal for all other FLUX
-    # models.
-    #
-    # We now use the `variant` field to directly represent the FLUX variant type, and `config_path` is no longer used.
 
     @classmethod
     def from_model_on_disk(cls, mod: ModelOnDisk, override_fields: dict[str, Any]) -> Self: