From a7e2bb86cbb168a8caa13a7d85278f57cffd6aaa Mon Sep 17 00:00:00 2001
From: Ethan P <eth-p+git@hidden.email>
Date: Wed, 8 May 2019 18:02:16 -0700
Subject: [PATCH] Add validation for --terminal-width option

---
 src/clap_app.rs | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/src/clap_app.rs b/src/clap_app.rs
index a3db2a13..e00d074d 100644
--- a/src/clap_app.rs
+++ b/src/clap_app.rs
@@ -331,6 +331,24 @@ pub fn build_app(interactive_output: bool) -> ClapApp<'static, 'static> {
                 .takes_value(true)
                 .value_name("width")
                 .hidden_short_help(true)
+                .validator(
+                    |t| {
+                        let sign = t.chars().next().unwrap();
+                        let num = if (sign == '+') || (sign == '-') {
+                            t.chars().skip(1).collect()
+                        } else {
+                            t
+                        };
+
+                        num.parse::<u32>()
+                            .map_err(|_e| "must be an offset or number")
+                            .and_then(|v| if v == 0 && sign != '+' && sign != '-' {
+                                Err("terminal width cannot be zero".into())
+                            } else {
+                                Ok(())
+                            })
+                            .map_err(|e| e.to_string())
+                    })
                 .help(
                     "Explicitly set the width of the terminal instead of determining it \
                      automatically. If prefixed with '+' or '-', the value will be treated \