From ec2bbb8e833d71119f853f3e1d3b3f9eea798cf7 Mon Sep 17 00:00:00 2001
From: Jordan Santell <jsantell@users.noreply.github.com>
Date: Fri, 17 Feb 2017 12:04:45 -0800
Subject: [PATCH] Ensure minimum rustc version in a build script. r=nalexander
 (#326)

Printing out failure to meet rustc version helps users during
setup with a helpful message if using an older rustc.
Rust version checking from http://stackoverflow.com/a/36607492.
---
 Cargo.toml       |  4 ++++
 build/version.rs | 26 ++++++++++++++++++++++++++
 2 files changed, 30 insertions(+)
 create mode 100644 build/version.rs

diff --git a/Cargo.toml b/Cargo.toml
index 770b3c95..6cbe021a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,6 +8,10 @@ authors = [
 ]
 name = "mentat"
 version = "0.4.0"
+build = "build/version.rs"
+
+[build-dependencies]
+rustc_version = "0.1.7"
 
 [dependencies]
 clap = "2.19.3"
diff --git a/build/version.rs b/build/version.rs
new file mode 100644
index 00000000..54f8b2a4
--- /dev/null
+++ b/build/version.rs
@@ -0,0 +1,26 @@
+// Copyright 2016 Mozilla
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+// this file except in compliance with the License. You may obtain a copy of the
+// License at http://www.apache.org/licenses/LICENSE-2.0
+// Unless required by applicable law or agreed to in writing, software distributed
+// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+// CONDITIONS OF ANY KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations under the License.
+
+extern crate rustc_version;
+
+use std::io::{self, Write};
+use std::process::exit;
+use rustc_version::version_matches;
+
+/// MIN_VERSION should be changed when there's a new minimum version of rustc required
+/// to build the project.
+static MIN_VERSION: &'static str  = ">= 1.15.1";
+
+fn main() {
+    if !version_matches(MIN_VERSION) {
+        writeln!(&mut io::stderr(), "Mentat requires rustc {}", MIN_VERSION).unwrap();
+        exit(1);
+    }
+}