fix(config): remove last used model data if it is damaged (#2580)

lua/avante/config.lua

@@ -684,13 +684,15 @@ M._defaults = {
 ---@diagnostic disable-next-line: missing-fields
 M._options = {}
 
+local function get_config_dir_path() return Utils.join_paths(vim.fn.expand("~"), ".config", "avante.nvim") end
+local function get_config_file_path() return Utils.join_paths(get_config_dir_path(), "config.json") end
+
 --- Function to save the last used model
 ---@param model_name string
 function M.save_last_model(model_name, provider_name)
-  local config_dir = Utils.join_paths(vim.fn.expand("~"), ".config", "avante.nvim")
-  local storage_path = Utils.join_paths(config_dir, "config.json")
+  local config_dir = get_config_dir_path()
+  local storage_path = get_config_file_path()
 
-  -- 确保目录存在
   if not Utils.path_exists(config_dir) then vim.fn.mkdir(config_dir, "p") end
 
   local file = io.open(storage_path, "w")
@@ -700,29 +702,64 @@ function M.save_last_model(model_name, provider_name)
   end
 end
 
---- Function to load the last used model
----@return string|nil, string|nil
-function M.load_last_model()
-  local config_dir = Utils.join_paths(vim.fn.expand("~"), ".config", "avante.nvim")
-  local storage_path = Utils.join_paths(config_dir, "config.json")
+--- Retrieves names of the last used model and provider. May remove saved config if it is deemed invalid
+---@param known_providers table<string, AvanteSupportedProvider>
+---@return string|nil Model name
+---@return string|nil Provider name
+function M.get_last_used_model(known_providers)
+  local storage_path = get_config_file_path()
   local file = io.open(storage_path, "r")
   if file then
     local content = file:read("*a")
     file:close()
-    if content and content ~= "" then
-      local success, data = pcall(vim.json.decode, content)
-      if success and data and data.last_model and data.last_provider then
-        return data.last_model, data.last_provider
-      elseif success and data and data.last_model then
-        return data.last_model, nil
-      else
-        Utils.warn("Invalid or corrupt JSON in last model file: " .. storage_path, { title = "Avante" })
-      end
-    else
-      Utils.warn("Last model file is empty: " .. storage_path, { title = "Avante" })
+
+    if not content or content == "" then
+      Utils.warn("Last used model file is empty: " .. storage_path)
+      -- Remove to not have repeated warnings
+      os.remove(storage_path)
     end
+
+    local success, data = pcall(vim.json.decode, content)
+    if not success or not data or not data.last_model or data.last_model == "" or data.last_provider == "" then
+      Utils.warn("Invalid or corrupt JSON in last used model file: " .. storage_path)
+      -- Rename instead of deleting so user can examine contents
+      os.rename(storage_path, storage_path .. ".bad")
+      return
+    end
+
+    if data.last_provider and not known_providers[data.last_provider] then
+      Utils.warn(
+        "Provider " .. data.last_provider .. " is no longer a valid provider, falling back to default configuration"
+      )
+      os.remove(storage_path)
+      return
+    end
+
+    return data.last_model, data.last_provider
+  end
+end
+
+---Applies given model and provider to the config
+---@param config avante.Config
+---@param model_name string
+---@param provider_name? string
+local function apply_model_selection(config, model_name, provider_name)
+  local provider_list = config.providers or {}
+  local current_provider_name = config.provider
+
+  local target_provider_name = provider_name or current_provider_name
+  local target_provider = provider_list[target_provider_name]
+
+  if not target_provider then return end
+
+  local current_provider_data = provider_list[current_provider_name]
+  local current_model_name = current_provider_data and current_provider_data.model
+
+  if target_provider_name ~= current_provider_name or model_name ~= current_model_name then
+    config.provider = target_provider_name
+    target_provider.model = model_name
+    Utils.info(string.format("Using previously selected model: %s/%s", target_provider_name, model_name))
   end
-  return nil
 end
 
 ---@param opts table<string, any>|nil -- Optional table parameter for configuration settings
@@ -861,23 +898,8 @@ function M.setup(opts)
     }
   )
 
-  local last_model, last_provider = M.load_last_model()
-  if last_model then
-    local original_provider = merged.provider
-    local original_model = merged.providers
-      and merged.providers[original_provider]
-      and merged.providers[original_provider].model
-    if last_provider then merged.provider = last_provider end
-    if merged.providers and merged.provider and merged.providers[merged.provider] then
-      merged.providers[merged.provider].model = last_model
-      if last_model ~= original_model or last_provider ~= original_provider then
-        Utils.info(
-          "Using last model: " .. merged.provider .. "/" .. merged.providers[merged.provider].model,
-          { title = "Avante" }
-        )
-      end
-    end
-  end
+  local last_model, last_provider = M.get_last_used_model(merged.providers or {})
+  if last_model then apply_model_selection(merged, last_model, last_provider) end
 
   M._options = merged