[PATCH] contrib: pick: bugfix when trying to show a non-message

[David Bremner]

Mark Walters <markwalters1009 at gmail.com> writes:

> -  (concat "id:\"" (notmuch-pick-get-prop :id) "\""))
> +  (let ((id (notmuch-pick-get-prop :id)))
> +    (when id
> +      (concat "id:\"" id "\""))))

I don't know how other people feel, but I'd rather have an `if' in a
context where I care about the return value.