enhance support for model switching and editing

- Error checks for invalid model
- Add !del_model command to invoke.py
- Add del_model() method to model_cache
- Autocompleter kept in sync with model addition/subtraction.

scripts/invoke.py

@@ -381,6 +381,15 @@ def do_command(command:str, gen, opt:Args, completer) -> tuple:
         completer.add_history(command)
         operation = None
 
+    elif command.startswith('!del'):
+        path = shlex.split(command)
+        if len(path) < 2:
+            print('** please provide the name of a model')
+        else:
+            del_config(path[1], gen, opt, completer)
+        completer.add_history(command)
+        operation = None
+
     elif command.startswith('!fetch'):
         file_path = command.replace('!fetch ','',1)
         retrieve_dream_command(opt,file_path,completer)
@@ -446,10 +455,23 @@ def add_weights_to_config(model_path:str, gen, opt, completer):
                 done = True
             except:
                 print('** Please enter a valid integer between 64 and 2048')
-
     if write_config_file(opt.conf, gen, model_name, new_config):
-        gen.set_model(model_name)
+        completer.add_model(model_name)
 
+def del_config(model_name:str, gen, opt, completer):
+    current_model = gen.model_name
+    if model_name == current_model:
+        print("** Can't delete active model. !switch to another model first. **")
+        return
+    yaml_str = gen.model_cache.del_model(model_name)
+    
+    tmpfile = os.path.join(os.path.dirname(opt.conf),'new_config.tmp')
+    with open(tmpfile, 'w') as outfile:
+        outfile.write(yaml_str)
+    os.rename(tmpfile,opt.conf)
+    print(f'** {model_name} deleted')
+    completer.del_model(model_name)
+    
 def edit_config(model_name:str, gen, opt, completer):
     config = gen.model_cache.config
     
@@ -467,11 +489,11 @@ def edit_config(model_name:str, gen, opt, completer):
         new_value = input(f'{field}: ')
         new_config[field] = int(new_value) if field in ('width','height') else new_value
     completer.complete_extensions(None)
-
-    if write_config_file(opt.conf, gen, model_name, new_config, clobber=True):
-        gen.set_model(model_name)
+    write_config_file(opt.conf, gen, model_name, new_config, clobber=True)
     
 def write_config_file(conf_path, gen, model_name, new_config, clobber=False):
+    current_model = gen.model_name
+    
     op = 'modify' if clobber else 'import'
     print('\n>> New configuration:')
     print(yaml.dump({model_name:new_config}))
@@ -479,15 +501,24 @@ def write_config_file(conf_path, gen, model_name, new_config, clobber=False):
         return False
 
     try:
+        print('>> Verifying that new model loads...')
         yaml_str = gen.model_cache.add_model(model_name, new_config, clobber)
+        assert gen.set_model(model_name) is not None, 'model failed to load'
     except AssertionError as e:
-        print(f'** configuration failed: {str(e)}')
+        print(f'** aborting **')
+        gen.model_cache.del_model(model_name)
         return False
     
     tmpfile = os.path.join(os.path.dirname(conf_path),'new_config.tmp')
     with open(tmpfile, 'w') as outfile:
         outfile.write(yaml_str)
     os.rename(tmpfile,conf_path)
+
+    do_switch = input(f'Keep model loaded? [y]')
+    if len(do_switch)==0 or do_switch[0] in ('y','Y'):
+        pass
+    else:
+        gen.set_model(current_model)
     return True
 
 def do_postprocess (gen, opt, callback):