Require -Zunstable-options to use @path

Author: jsgf

src/librustc_driver/args/mod.rs

@@ -4,10 +4,17 @@ use std::fmt;
 use std::fs;
 use std::io::{self, BufRead};
 use std::str;
+use std::sync::atomic::{AtomicBool, Ordering};
 
 #[cfg(test)]
 mod tests;
 
+static USED_ARGSFILE_FEATURE: AtomicBool = AtomicBool::new(false);
+
+pub fn used_unstable_argsfile() -> bool {
+    USED_ARGSFILE_FEATURE.load(Ordering::Relaxed)
+}
+
 struct FileArgs {
     path: String,
     input: Vec<u8>,
@@ -60,7 +67,10 @@ impl Iterator for ArgsIter {
                 Some(Ok(ref arg)) if arg.starts_with("@") => {
                     let path = &arg[1..];
                     let lines = match fs::read(path) {
-                        Ok(file) => FileArgs::new(path.to_string(), file).lines(),
+                        Ok(file) => {
+                            USED_ARGSFILE_FEATURE.store(true, Ordering::Relaxed);
+                            FileArgs::new(path.to_string(), file).lines()
+                        }
                         Err(err) => return Some(Err(Error::IOError(path.to_string(), err))),
                     };
                     self.file = Some(Box::new(lines));

src/librustc_driver/lib.rs

@@ -778,7 +778,7 @@ fn usage(verbose: bool, include_unstable_options: bool) {
     } else {
         "\n    --help -v           Print the full set of options rustc accepts"
     };
-    let at_path = if verbose {
+    let at_path = if verbose && nightly_options::is_nightly_build() {
         "    @path               Read newline separated options from `path`\n"
     } else {
         ""
@@ -1015,6 +1015,12 @@ pub fn handle_options(args: &[String]) -> Option<getopts::Matches> {
     //   (unstable option being used on stable)
     nightly_options::check_nightly_options(&matches, &config::rustc_optgroups());
 
+    // Late check to see if @file was used without unstable options enabled
+    if crate::args::used_unstable_argsfile() && !nightly_options::is_unstable_enabled(&matches) {
+        early_error(ErrorOutputType::default(),
+            "@path is unstable - use -Z unstable-options to enable its use");
+    }
+
     if matches.opt_present("h") || matches.opt_present("help") {
         // Only show unstable options in --help if we accept unstable options.
         usage(matches.opt_present("verbose"), nightly_options::is_unstable_enabled(&matches));