Add checking if the build directory exists and move expression after docstring

tools/idf_py_actions/serial_ext.py

@@ -115,6 +115,7 @@ def action_extensions(base_actions, project_path):
         """
         Run esptool to flash the entire project, from an argfile generated by the build system
         """
+        ensure_build_directory(args, ctx.info_name)
         flasher_args_path = {
             # action -> name of flasher args file generated by build system
             "bootloader-flash": "flash_bootloader_args",
@@ -129,6 +130,7 @@ def action_extensions(base_actions, project_path):
         run_tool("esptool.py", esptool_args, args.build_dir)
 
     def erase_flash(action, ctx, args):
+        ensure_build_directory(args, ctx.info_name)
         esptool_args = _get_esptool_args(args)
         esptool_args += ["erase_flash"]
         run_tool("esptool.py", esptool_args, args.build_dir)