From 96bbd8a26e3d4af9b897f0b3773bff45ac50577a Mon Sep 17 00:00:00 2001
From: psychedelicious <4822129+psychedelicious@users.noreply.github.com>
Date: Thu, 25 Sep 2025 20:48:43 +1000
Subject: [PATCH] fix(mm): t2i base determination

---
 invokeai/backend/model_manager/config.py | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/invokeai/backend/model_manager/config.py b/invokeai/backend/model_manager/config.py
index 5fc22be845..7230c46c74 100644
--- a/invokeai/backend/model_manager/config.py
+++ b/invokeai/backend/model_manager/config.py
@@ -1225,9 +1225,8 @@ class CLIPVisionDiffusersConfig(DiffusersConfigBase, ModelConfigBase):
         return cls(**fields)
 
 
-T2IAdapterCheckpoint_SupportedBases: TypeAlias = Literal[
+T2IAdapterDiffusers_SupportedBases: TypeAlias = Literal[
     BaseModelType.StableDiffusion1,
-    BaseModelType.StableDiffusion2,
     BaseModelType.StableDiffusionXL,
 ]
 
@@ -1235,7 +1234,7 @@ T2IAdapterCheckpoint_SupportedBases: TypeAlias = Literal[
 class T2IAdapterConfig(DiffusersConfigBase, ControlAdapterConfigBase, ModelConfigBase):
     """Model config for T2I."""
 
-    base: T2IAdapterCheckpoint_SupportedBases = Field()
+    base: T2IAdapterDiffusers_SupportedBases = Field()
     type: Literal[ModelType.T2IAdapter] = Field(default=ModelType.T2IAdapter)
     format: Literal[ModelFormat.Diffusers] = Field(default=ModelFormat.Diffusers)
 
@@ -1248,6 +1247,7 @@ class T2IAdapterConfig(DiffusersConfigBase, ControlAdapterConfigBase, ModelConfi
         "T2IAdapter",
     }
 
+
     @classmethod
     def from_model_on_disk(cls, mod: ModelOnDisk, fields: dict[str, Any]) -> Self:
         _raise_if_not_dir(cls, mod)
@@ -1258,8 +1258,23 @@ class T2IAdapterConfig(DiffusersConfigBase, ControlAdapterConfigBase, ModelConfi
 
         _validate_class_names(cls, config_path, cls.VALID_CLASS_NAMES)
 
-        return cls(**fields)
+        base = fields.get("base") or cls._get_base_or_raise(mod)
 
+        return cls(**fields, base=base)
+
+    @classmethod
+    def _get_base_or_raise(cls, mod: ModelOnDisk) -> T2IAdapterDiffusers_SupportedBases:
+        config = _get_config_or_raise(cls, mod.path / "config.json")
+
+        adapter_type = config.get("adapter_type")
+
+        match adapter_type:
+            case "full_adapter_xl":
+                return BaseModelType.StableDiffusionXL
+            case "full_adapter" | "light_adapter":
+                return BaseModelType.StableDiffusion1
+            case _:
+                raise NotAMatch(cls, f"unrecognized adapter_type '{adapter_type}'")
 
 class SpandrelImageToImageConfig(ModelConfigBase):
     """Model config for Spandrel Image to Image models."""