Use --version --verbose to get rustc version out of clippy-driver

Fixes issue dtolnay#13

build/build.rs

@@ -8,11 +8,17 @@ use std::process::{self, Command};
 
 fn main() {
  let rustc = env::var_os("RUSTC").unwrap_or_else(|| OsString::from("rustc"));
- let output = match Command::new(&rustc).arg("--version").output() {
+ let output = match Command::new(&rustc)
+ .args(&["--version", "--verbose"])
+ .output()
+ {
  Ok(output) => output,
  Err(e) => {
  let rustc = rustc.to_string_lossy();
- eprintln!("Error: failed to run `{} --version`: {}", rustc, e);
+ eprintln!(
+ "Error: failed to run `{} --version --verbose`: {}",
+ rustc, e
+ );
  process::exit(1);
  }
  };

build/rustc.rs

@@ -26,8 +26,10 @@ pub struct Date {
 }
 
 pub fn parse(string: &str) -> Option<Version> {
- let last_line = string.lines().last().unwrap_or(&string);
- let mut words = last_line.trim().split(' ');
+ let rustc_line = string
+ .lines()
+ .find(|l| l.trim_start().starts_with("rustc "))?;
+ let mut words = rustc_line.trim().split(' ');
 
  if words.next()? != "rustc" {
  return None;

tests/test_parse.rs

@@ -79,6 +79,12 @@ fn test_parse() {
  ];
 
  for (string, expected) in cases {
- assert_eq!(parse(string).unwrap(), *expected);
+ assert_eq!(
+ parse(string).as_ref(),
+ Some(expected),
+ "string {} expected {:#?}",
+ string,
+ expected
+ );
  }
 }