fix: gemini ReAct (#2132)

lua/avante/providers/gemini.lua

@@ -123,6 +123,12 @@ function M:parse_messages(opts)
             end
           end
           if tool_use then
+            table.insert(contents, {
+              role = "model",
+              parts = {
+                { text = Utils.tool_use_to_xml(tool_use.content[1]) },
+              },
+            })
             role = "user"
             table.insert(parts, {
               text = "["
@@ -187,9 +193,11 @@ function M.prepare_request_body(provider_instance, prompt_opts, provider_conf, r
   request_body.temperature = nil
   request_body.max_tokens = nil
 
+  local use_ReAct_prompt = provider_conf.use_ReAct_prompt == true
+
   local disable_tools = provider_conf.disable_tools or false
 
-  if not disable_tools and prompt_opts.tools then
+  if not use_ReAct_prompt and not disable_tools and prompt_opts.tools then
     local function_declarations = {}
     for _, tool in ipairs(prompt_opts.tools) do
       table.insert(function_declarations, provider_instance:transform_to_function_declaration(tool))
@@ -229,7 +237,7 @@ function M:parse_response(ctx, data_stream, _, opts)
   if json.candidates and #json.candidates > 0 then
     local candidate = json.candidates[1]
     ---@type AvanteLLMToolUse[]
-    local tool_use_list = {}
+    ctx.tool_use_list = ctx.tool_use_list or {}
 
     -- Check if candidate.content and candidate.content.parts exist before iterating
     if candidate.content and candidate.content.parts then
@@ -245,7 +253,7 @@ function M:parse_response(ctx, data_stream, _, opts)
             name = part.functionCall.name,
             input_json = vim.json.encode(part.functionCall.args),
           }
-          table.insert(tool_use_list, tool_use)
+          table.insert(ctx.tool_use_list, tool_use)
           OpenAI:add_tool_use_message(tool_use, "generated", opts)
         end
       end
@@ -262,7 +270,7 @@ function M:parse_response(ctx, data_stream, _, opts)
         -- The tool_use list is added to the table in llm.lua
         opts.on_stop(vim.tbl_deep_extend("force", { reason = "tool_use" }, stop_details))
       elseif reason_str == "STOP" then
-        if #tool_use_list > 0 then
+        if ctx.tool_use_list and #ctx.tool_use_list > 0 then
           -- Natural stop, but tools were found in this final chunk.
           opts.on_stop(vim.tbl_deep_extend("force", { reason = "tool_use" }, stop_details))
         else