if kitchen cannot read recipe engine result file (e.g. it does not exist), it crashes with an error message saying it cannot do that

(env omitted)
----------------------------------- RESULTS ------------------------------------
kitchen_error: <
  text: "could not read recipe result file at \"e:\\\\b\\\\swarm_slave\\\\w\\\\ir\\\\tmp\\\\recipe-result.json\": open e:\\b\\swarm_slave\\w\\ir\\tmp\\recipe-result.json: The system cannot find the file specified."
  call_stack: "original error: open e:\\b\\swarm_slave\\w\\ir\\tmp\\recipe-result.json: The system cannot find the file specified."
  call_stack: ""
  call_stack: "goroutine 1:"
  call_stack: "#0 kitchen/cook.go:360 - main.(*cookRun).ensureAndRunRecipe()"
  call_stack: "  reason: \"could not read recipe result file at \\\"e:\\\\\\\\b\\\\\\\\swarm_slave\\\\\\\\w\\\\\\\\ir\\\\\\\\tmp\\\\\\\\recipe-result.json\\\"\""
  call_stack: "  \"path\" = \"e:\\\\b\\\\swarm_slave\\\\w\\\\ir\\\\tmp\\\\recipe-result.json\""
  call_stack: ""
  call_stack: "#1 kitchen/cook.go:619 - main.(*cookRun).run()"
  call_stack: "#2 kitchen/cook.go:519 - main.(*cookRun).Run()"
  call_stack: "#3 github.com/maruel/subcommands/subcommands.go:360 - subcommands.Run()"
  call_stack: "#4 kitchen/kitchen.go:52 - main.main()"
  call_stack: "#5 runtime/proc.go:185 - runtime.main()"
  call_stack: "#6 runtime/asm_amd64.s:2197 - runtime.goexit()"
>
recipe_exit_code: <
  value: 1
>
annotations: <
  command: <
    command_line: "python"
    command_line: "kitchen-checkout\\recipes\\recipes.py"
    command_line: "--operational-args-path"
    command_line: "e:\\b\\swarm_slave\\w\\ir\\tmp\\rr\\op_args.json"
    command_line: "run"
    command_line: "--properties-file"
    command_line: "e:\\b\\swarm_slave\\w\\ir\\tmp\\rr\\properties.json"
    command_line: "--workdir"
    command_line: "e:\\b\\swarm_slave\\w\\ir\\kitchen-workdir"
    command_line: "--output-result-json"
    command_line: "e:\\b\\swarm_slave\\w\\ir\\tmp\\recipe-result.json"
    command_line: "infra_continuous_luci"
    cwd: "e:\\b\\swarm_slave\\w\\ir"
  >
  status: SUCCESS
  stderr_stream: <
    name: "stderr"
  >
  started: <
    seconds: 1494525160
    nanos: 46038500
  >
>
annotation_url: "logdog://luci-logdog-dev.appspot.com/infra/buildbucket/cr-buildbucket-dev.appspot.com/8979870614528752144/+/annotations"
--------------------------------------------------------------------------------


for someone unfamiliar with kitchen, this is hard to debug. The error is hidden in the recipe engine stderr:

$ logdog cat 'logdog://luci-logdog-dev.appspot.com/infra/buildbucket/cr-buildbucket-dev.appspot.com/8979870614528752144/+/stderr'
Traceback (most recent call last):
  File "e:\b\swarm_slave\w\ir\kitchen-checkout\recipes\.recipe_deps\recipe_engine\recipes.py", line 147, in <module>
    ret = main()
  File "e:\b\swarm_slave\w\ir\kitchen-checkout\recipes\.recipe_deps\recipe_engine\recipes.py", line 133, in main
    context, args.package, overrides=args.project_override)
  File "e:\b\swarm_slave\w\ir\kitchen-checkout\recipes\.recipe_deps\recipe_engine\recipe_engine\package.py", line 443, in create
    context, RootRepoSpec(package_file))
  File "e:\b\swarm_slave\w\ir\kitchen-checkout\recipes\.recipe_deps\recipe_engine\recipe_engine\package.py", line 469, in _create_package
    deps[dep] = self._create_package(context, dep_repo)
  File "e:\b\swarm_slave\w\ir\kitchen-checkout\recipes\.recipe_deps\recipe_engine\recipe_engine\package.py", line 449, in _create_package
    context, repo_spec.spec_pb())
  File "e:\b\swarm_slave\w\ir\kitchen-checkout\recipes\.recipe_deps\recipe_engine\recipe_engine\package.py", line 182, in spec_pb
    return self.current().spec
  File "e:\b\swarm_slave\w\ir\kitchen-checkout\recipes\.recipe_deps\recipe_engine\recipe_engine\package.py", line 201, in current
    return self.backend.commit_metadata(self.revision)
  File "e:\b\swarm_slave\w\ir\kitchen-checkout\recipes\.recipe_deps\recipe_engine\recipe_engine\fetch.py", line 109, in commit_metadata
    cache[revision] = self._commit_metadata_impl(revision)
  File "e:\b\swarm_slave\w\ir\kitchen-checkout\recipes\.recipe_deps\recipe_engine\recipe_engine\fetch.py", line 369, in _commit_metadata_impl
    'diff-tree', '-r', '--no-commit-id', '--name-only', '%s^!' % revision)
  File "e:\b\swarm_slave\w\ir\kitchen-checkout\recipes\.recipe_deps\recipe_engine\recipe_engine\fetch.py", line 245, in _git
    raise GitError('Git "%s" failed: %s' % (subcommand, e.message,))
GitError: Git "diff-tree" failed:
Uncaught exception (GitError): Git "diff-tree" failed:

------------


We can solve problem by retaining recipe engine's stdio in kitchen, or making recipe engine always dump a result file, even on internal errors. In this case, the failure should specify "Uncaught exception (GitError): Git "diff-tree" failed:" or something like that