fix: exit codes for indirect tasks

[pd93]

Fixes #1266

This bug is happening because when we run a command, we are always wrapping the interp.exitStatus error and returning a TaskRunError:

task/task.go

Lines 232 to 243 in 7e7a016

	if err := e.runCommand(ctx, t, call, i); err != nil {
	if err2 := e.statusOnError(t); err2 != nil {
	e.Logger.VerboseErrf(logger.Yellow, "task: error cleaning status on error: %v\n", err2)
	}
	if execext.IsExitError(err) && t.IgnoreError {
	e.Logger.VerboseErrf(logger.Yellow, "task: task error ignored: %v\n", err)
	continue
	}
	return &errors.TaskRunError{TaskName: t.Task, Err: err}
	}

This works fine at the top-level (for direct calls) because we can simply unwrap the error in Task's main function:

task/cmd/task/task.go

Lines 84 to 87 in 7e7a016

	if err, ok := err.(*errors.TaskRunError); ok && flags.exitCode {
	l.Errf(logger.Red, "%v\n", err)
	os.Exit(err.TaskExitCode())
	}

However, when we run a command indirectly via another task, we are wrapping the TaskRunError in another TaskRunError. This problem is recursive and means that we can't effectively unwrap the error to get the exit code out.

The solution to this is simply to check if the command is being called directly and if not, we return the interp.exitStatus directly instead of wrapping it up. This means that we only wrap once on the top-level error and unwrapping in the main function just works.

I've also updated the tests to cover this case.

[andreynering]

Thanks!