fix bugs in online ckpt conversion of 2.0 models

This commit fixes bugs related to the on-the-fly conversion and loading of
legacy checkpoint models built on SD-2.0 base.

- When legacy checkpoints built on SD-2.0 models were converted
  on-the-fly using --ckpt_convert, generation would crash with a
  precision incompatibility error.

- In addition, broken logic was causing some 2.0-derived ckpt files to
  be converted into diffusers and then processed through the legacy
  generation routines - not good.

ldm/invoke/CLI.py

@@ -772,11 +772,11 @@ def convert_model(model_name_or_path: Union[Path, str], gen, opt, completer):
             original_config_file = Path(model_info["config"])
             model_name = model_name_or_path
             model_description = model_info["description"]
-            vae = model_info["vae"]
+            vae = model_info.get("vae")
         else:
             print(f"** {model_name_or_path} is not a legacy .ckpt weights file")
             return
-        if vae_repo := ldm.invoke.model_manager.VAE_TO_REPO_ID.get(Path(vae).stem):
+        if vae and (vae_repo := ldm.invoke.model_manager.VAE_TO_REPO_ID.get(Path(vae).stem)):
             vae_repo = dict(repo_id=vae_repo)
         else:
             vae_repo = None

ldm/invoke/ckpt_to_diffuser.py

@@ -1264,10 +1264,10 @@ def load_pipeline_from_original_stable_diffusion_ckpt(
                 cache_dir=cache_dir,
             )
             pipe = pipeline_class(
-                vae=vae,
-                text_encoder=text_model,
+                vae=vae.to(precision),
+                text_encoder=text_model.to(precision),
                 tokenizer=tokenizer,
-                unet=unet,
+                unet=unet.to(precision),
                 scheduler=scheduler,
                 safety_checker=None,
                 feature_extractor=None,

ldm/invoke/model_manager.py

@@ -172,9 +172,9 @@ class ModelManager(object):
         """
         # if we are converting legacy files automatically, then
         # there are no legacy ckpts!
-        if Globals.ckpt_convert:
-            return False
         info = self.model_info(model_name)
+        if Globals.ckpt_convert or info.format=='diffusers' or self.is_v2_config(info.config):
+            return False
         if "weights" in info and info["weights"].endswith((".ckpt", ".safetensors")):
             return True
         return False
@@ -544,6 +544,8 @@ class ModelManager(object):
         return pipeline, width, height, model_hash
 
     def is_v2_config(self, config: Path) -> bool:
+        if not os.path.isabs(config):
+            config = os.path.join(Globals.root, config)
         try:
             mconfig = OmegaConf.load(config)
             return (