add an option to copy config from one of models in checkpoint merger

import os

import sys

import traceback

import shutil

import numpy as np

from PIL import Image

    return '', geninfo, info

def run_modelmerger(primary_model_name, secondary_model_name, tertiary_model_name, interp_method, multiplier, save_as_half, custom_name, checkpoint_format):

def create_config(ckpt_result, config_source, a, b, c):

    def config(x):

        return sd_models.find_checkpoint_config(x) if x else None

    if config_source == 0:

        cfg = config(a) or config(b) or config(c)

    elif config_source == 1:

        cfg = config(b)

    elif config_source == 2:

        cfg = config(c)

    else:

        cfg = None

    if cfg is None:

        return

    filename, _ = os.path.splitext(ckpt_result)

    checkpoint_filename = filename + ".yaml"

    print("Copying config:")

    print("   from:", cfg)

    print("     to:", checkpoint_filename)

    shutil.copyfile(cfg, checkpoint_filename)

def run_modelmerger(primary_model_name, secondary_model_name, tertiary_model_name, interp_method, multiplier, save_as_half, custom_name, checkpoint_format, config_source):

    shared.state.begin()

    shared.state.job = 'model-merge'

    sd_models.list_models()

    create_config(output_modelname, config_source, primary_model_info, secondary_model_info, tertiary_model_info)

    print("Checkpoint saved.")

    shared.state.textinfo = "Checkpoint saved to " + output_modelname

    shared.state.end()

            with gr.Column(variant='panel'):

                gr.HTML(value="<p>A merger of the two checkpoints will be generated in your <b>checkpoint</b> directory.</p>")

                with gr.Row():

                with FormRow():

                    primary_model_name = gr.Dropdown(modules.sd_models.checkpoint_tiles(), elem_id="modelmerger_primary_model_name", label="Primary model (A)")

                    create_refresh_button(primary_model_name, modules.sd_models.list_models, lambda: {"choices": modules.sd_models.checkpoint_tiles()}, "refresh_checkpoint_A")

                interp_amount = gr.Slider(minimum=0.0, maximum=1.0, step=0.05, label='Multiplier (M) - set to 0 to get model A', value=0.3, elem_id="modelmerger_interp_amount")

                interp_method = gr.Radio(choices=["Weighted sum", "Add difference"], value="Weighted sum", label="Interpolation Method", elem_id="modelmerger_interp_method")

                with gr.Row():

                with FormRow():

                    checkpoint_format = gr.Radio(choices=["ckpt", "safetensors"], value="ckpt", label="Checkpoint format", elem_id="modelmerger_checkpoint_format")

                    save_as_half = gr.Checkbox(value=False, label="Save as float16", elem_id="modelmerger_save_as_half")

                modelmerger_merge = gr.Button(elem_id="modelmerger_merge", label="Merge", variant='primary')

                config_source = gr.Radio(choices=["A, B or C", "B", "C", "Don't"], value="A, B or C", label="Copy config from", type="index", elem_id="modelmerger_config_method")

                modelmerger_merge = gr.Button(elem_id="modelmerger_merge", value="Merge", variant='primary')

            with gr.Column(variant='panel'):

                submit_result = gr.Textbox(elem_id="modelmerger_result", show_label=False)

                save_as_half,

                custom_name,

                checkpoint_format,

                config_source,

            ],

            outputs=[

                submit_result,