fix formatting bugs in both textual_inversion and merge front ends

- Issue is that if insufficient diffusers models are defined in
  models.yaml the frontend would ungraciously crash.

- Now it emits appropriate error messages telling user what the problem
  is.

ldm/invoke/merge_diffusers.py

@@ -15,20 +15,18 @@ from pathlib import Path
 from typing import List, Union
 
 import npyscreen
-from diffusers import DiffusionPipeline, logging as dlogging
+from diffusers import DiffusionPipeline
+from diffusers import logging as dlogging
+from npyscreen import widget
 from omegaconf import OmegaConf
 
-from ldm.invoke.globals import (
+from ldm.invoke.globals import (Globals, global_cache_dir, global_config_file,
-    Globals,
+                                global_models_dir, global_set_root)
-    global_cache_dir,
-    global_config_file,
-    global_models_dir,
-    global_set_root,
-)
 from ldm.invoke.model_manager import ModelManager
 
 DEST_MERGED_MODEL_DIR = "merged_models"
 
+
 def merge_diffusion_models(
     model_ids_or_paths: List[Union[str, Path]],
     alpha: float = 0.5,
@@ -48,7 +46,7 @@ def merge_diffusion_models(
          cache_dir, resume_download, force_download, proxies, local_files_only, use_auth_token, revision, torch_dtype, device_map
     """
     with warnings.catch_warnings():
-        warnings.simplefilter('ignore')
+        warnings.simplefilter("ignore")
         verbosity = dlogging.get_verbosity()
         dlogging.set_verbosity_error()
 
@@ -188,7 +186,6 @@ class FloatTitleSlider(npyscreen.TitleText):
 
 
 class mergeModelsForm(npyscreen.FormMultiPageAction):
-
     interpolations = ["weighted_sum", "sigmoid", "inv_sigmoid", "add_difference"]
 
     def __init__(self, parentApp, name):
@@ -214,20 +211,20 @@ class mergeModelsForm(npyscreen.FormMultiPageAction):
 
         self.add_widget_intelligent(
             npyscreen.FixedText,
-            color='CONTROL',
+            color="CONTROL",
             value=f"Select two models to merge and optionally a third.",
             editable=False,
         )
         self.add_widget_intelligent(
             npyscreen.FixedText,
-            color='CONTROL',
+            color="CONTROL",
             value=f"Use up and down arrows to move, <space> to select an item, <tab> and <shift-tab> to move from one field to the next.",
             editable=False,
         )
         self.add_widget_intelligent(
             npyscreen.FixedText,
-            value='MODEL 1',
+            value="MODEL 1",
-            color='GOOD',
+            color="GOOD",
             editable=False,
             rely=4 if horizontal_layout else None,
         )
@@ -242,15 +239,15 @@ class mergeModelsForm(npyscreen.FormMultiPageAction):
         )
         self.add_widget_intelligent(
             npyscreen.FixedText,
-            value='MODEL 2',
+            value="MODEL 2",
-            color='GOOD',
+            color="GOOD",
             editable=False,
             relx=max_width + 3 if horizontal_layout else None,
             rely=4 if horizontal_layout else None,
         )
         self.model2 = self.add_widget_intelligent(
             npyscreen.SelectOne,
-            name='(2)',
+            name="(2)",
             values=self.model_names,
             value=1,
             max_height=len(self.model_names),
@@ -261,17 +258,17 @@ class mergeModelsForm(npyscreen.FormMultiPageAction):
         )
         self.add_widget_intelligent(
             npyscreen.FixedText,
-            value='MODEL 3',
+            value="MODEL 3",
-            color='GOOD',
+            color="GOOD",
             editable=False,
             relx=max_width * 2 + 3 if horizontal_layout else None,
             rely=4 if horizontal_layout else None,
         )
         models_plus_none = self.model_names.copy()
-        models_plus_none.insert(0,'None')
+        models_plus_none.insert(0, "None")
         self.model3 = self.add_widget_intelligent(
             npyscreen.SelectOne,
-            name='(3)',
+            name="(3)",
             values=models_plus_none,
             value=0,
             max_height=len(self.model_names) + 1,
@@ -285,14 +282,14 @@ class mergeModelsForm(npyscreen.FormMultiPageAction):
         self.merged_model_name = self.add_widget_intelligent(
             npyscreen.TitleText,
             name="Name for merged model:",
-            labelColor='CONTROL',
+            labelColor="CONTROL",
             value="",
             scroll_exit=True,
         )
         self.force = self.add_widget_intelligent(
             npyscreen.Checkbox,
             name="Force merge of incompatible models",
-            labelColor='CONTROL',
+            labelColor="CONTROL",
             value=False,
             scroll_exit=True,
         )
@@ -301,7 +298,7 @@ class mergeModelsForm(npyscreen.FormMultiPageAction):
             name="Merge Method:",
             values=self.interpolations,
             value=0,
-            labelColor='CONTROL',
+            labelColor="CONTROL",
             max_height=len(self.interpolations) + 1,
             scroll_exit=True,
         )
@@ -312,7 +309,7 @@ class mergeModelsForm(npyscreen.FormMultiPageAction):
             step=0.05,
             lowest=0,
             value=0.5,
-            labelColor='CONTROL',
+            labelColor="CONTROL",
             scroll_exit=True,
         )
         self.model1.editing = True
@@ -322,12 +319,12 @@ class mergeModelsForm(npyscreen.FormMultiPageAction):
         selected_model1 = self.model1.value[0]
         selected_model2 = self.model2.value[0]
         selected_model3 = self.model3.value[0]
-        merged_model_name = f'{models[selected_model1]}+{models[selected_model2]}'
+        merged_model_name = f"{models[selected_model1]}+{models[selected_model2]}"
         self.merged_model_name.value = merged_model_name
 
         if selected_model3 > 0:
-            self.merge_method.values=['add_difference'],
+            self.merge_method.values = (["add_difference"],)
-            self.merged_model_name.value += f'+{models[selected_model3]}'
+            self.merged_model_name.value += f"+{models[selected_model3]}"
         else:
             self.merge_method.values = self.interpolations
         self.merge_method.value = 0
@@ -337,7 +334,7 @@ class mergeModelsForm(npyscreen.FormMultiPageAction):
             self.parentApp.setNextForm(None)
             self.editing = False
             self.parentApp.merge_arguments = self.marshall_arguments()
-            npyscreen.notify('Starting the merge...')
+            npyscreen.notify("Starting the merge...")
         else:
             self.editing = True
 
@@ -374,15 +371,19 @@ class mergeModelsForm(npyscreen.FormMultiPageAction):
     def validate_field_values(self) -> bool:
         bad_fields = []
         model_names = self.model_names
-        selected_models = set((model_names[self.model1.value[0]],model_names[self.model2.value[0]]))
+        selected_models = set(
+            (model_names[self.model1.value[0]], model_names[self.model2.value[0]])
+        )
         if self.model3.value[0] > 0:
             selected_models.add(model_names[self.model3.value[0] - 1])
         if len(selected_models) < 2:
-            bad_fields.append(f'Please select two or three DIFFERENT models to compare. You selected {selected_models}')
+            bad_fields.append(
+                f"Please select two or three DIFFERENT models to compare. You selected {selected_models}"
+            )
         if len(bad_fields) > 0:
-            message = 'The following problems were detected and must be corrected:'
+            message = "The following problems were detected and must be corrected:"
             for problem in bad_fields:
-                message += f'\n* {problem}'
+                message += f"\n* {problem}"
             npyscreen.notify_confirm(message)
             return False
         else:
@@ -410,6 +411,7 @@ class Mergeapp(npyscreen.NPSAppManaged):
         npyscreen.setTheme(npyscreen.Themes.ElegantTheme)
         self.main = self.addForm("MAIN", mergeModelsForm, name="Merge Models Settings")
 
+
 def run_gui(args: Namespace):
     mergeapp = Mergeapp()
     mergeapp.run()
@@ -450,5 +452,27 @@ def main():
     ] = cache_dir  # because not clear the merge pipeline is honoring cache_dir
     args.cache_dir = cache_dir
 
+    try:
+        if args.front_end:
+            run_gui(args)
+        else:
+            run_cli(args)
+        print(f">> Conversion successful. New model is named {args.merged_model_name}")
+    except widget.NotEnoughSpaceForWidget as e:
+        if str(e).startswith("Height of 1 allocated"):
+            print(
+                "** You need to have at least two diffusers models defined in models.yaml in order to merge"
+            )
+        else:
+            print(f"** A layout error has occurred: {str(e)}")
+        sys.exit(-1)
+    except Exception as e:
+        print(">> An error occurred:")
+        traceback.print_exc()
+        sys.exit(-1)
+    except KeyboardInterrupt:
+        sys.exit(-1)
+
+
 if __name__ == "__main__":
     main()

ldm/invoke/training/textual_inversion.py

@@ -17,6 +17,7 @@ from pathlib import Path
 from typing import List, Tuple
 
 import npyscreen
+from npyscreen import widget
 from omegaconf import OmegaConf
 
 from ldm.invoke.globals import Globals, global_set_root
@@ -438,11 +439,20 @@ def main():
             do_front_end(args)
         else:
             do_textual_inversion_training(**vars(args))
+    except widget.NotEnoughSpaceForWidget as e:
+        if str(e).startswith("Height of 1 allocated"):
+            print(
+                "** You need to have at least one diffusers models defined in models.yaml in order to train"
+            )
+        else:
+            print(f"** A layout error has occurred: {str(e)}")
+        sys.exit(-1)
     except AssertionError as e:
         print(str(e))
         sys.exit(-1)
     except KeyboardInterrupt:
         pass
 
+
 if __name__ == "__main__":
     main()