Suppress unstable config options by default.

This commit suppresses the output of unstable config options by default.

Users can specify the `--unstable-features` option to show the config options
that are unstable.

Fixes #2611.

Author: Peter Huene

src/bin/main.rs

@@ -15,7 +15,7 @@ extern crate getopts;
 extern crate rustfmt_nightly as rustfmt;
 
 use std::fs::File;
-use std::io::{self, Read, Write};
+use std::io::{self, stdout, Read, Write};
 use std::path::{Path, PathBuf};
 use std::str::FromStr;
 use std::{env, error};
@@ -226,7 +226,7 @@ fn execute(opts: &Options) -> FmtResult<Summary> {
             Ok(Summary::default())
         }
         Operation::ConfigHelp => {
-            Config::print_docs();
+            Config::print_docs(&mut stdout(), matches.opt_present("unstable-features"));
             Ok(Summary::default())
         }
         Operation::ConfigOutputDefault { path } => {

src/config/config_type.rs

@@ -81,6 +81,7 @@ macro_rules! is_nightly_channel {
 macro_rules! create_config {
     ($($i:ident: $ty:ty, $def:expr, $stb:expr, $( $dstring:expr ),+ );+ $(;)*) => (
         use std::collections::HashSet;
+        use std::io::Write;
 
         #[derive(Clone)]
         pub struct Config {
@@ -359,33 +360,36 @@ macro_rules! create_config {
                 HIDE_OPTIONS.contains(&name)
             }
 
-            pub fn print_docs() {
+            pub fn print_docs(out: &mut Write, include_unstable: bool) {
                 use std::cmp;
                 let max = 0;
                 $( let max = cmp::max(max, stringify!($i).len()+1); )+
                 let mut space_str = String::with_capacity(max);
                 for _ in 0..max {
                     space_str.push(' ');
                 }
-                println!("Configuration Options:");
+                writeln!(out, "Configuration Options:").unwrap();
                 $(
-                    let name_raw = stringify!($i);
-
-                    if !Config::is_hidden_option(name_raw) {
-                        let mut name_out = String::with_capacity(max);
-                        for _ in name_raw.len()..max-1 {
-                            name_out.push(' ')
+                    if $stb || include_unstable {
+                        let name_raw = stringify!($i);
+
+                        if !Config::is_hidden_option(name_raw) {
+                            let mut name_out = String::with_capacity(max);
+                            for _ in name_raw.len()..max-1 {
+                                name_out.push(' ')
+                            }
+                            name_out.push_str(name_raw);
+                            name_out.push(' ');
+                            writeln!(out,
+                                    "{}{} Default: {:?}",
+                                    name_out,
+                                    <$ty>::doc_hint(),
+                                    $def).unwrap();
+                            $(
+                                writeln!(out, "{}{}", space_str, $dstring).unwrap();
+                            )+
+                            writeln!(out).unwrap();
                         }
-                        name_out.push_str(name_raw);
-                        name_out.push(' ');
-                        println!("{}{} Default: {:?}",
-                                name_out,
-                                <$ty>::doc_hint(),
-                                $def);
-                        $(
-                            println!("{}{}", space_str, $dstring);
-                        )+
-                        println!();
                     }
                 )+
             }

src/config/mod.rs

@@ -181,6 +181,7 @@ pub fn get_toml_path(dir: &Path) -> Result<Option<PathBuf>, Error> {
 #[cfg(test)]
 mod test {
     use super::Config;
+    use std::str;
 
     #[test]
     fn test_config_set() {
@@ -218,6 +219,27 @@ mod test {
         assert_eq!(config.was_set().verbose(), false);
     }
 
+    #[test]
+    fn test_print_docs_without_unstable() {
+        let mut output = Vec::new();
+        Config::print_docs(&mut output, false);
+
+        let s = str::from_utf8(&output).unwrap();
+
+        assert_eq!(s.contains("newline_style"), true);
+        assert_eq!(s.contains("use_small_heuristics"), false);
+    }
+
+    #[test]
+    fn test_print_docs_with_unstable() {
+        let mut output = Vec::new();
+        Config::print_docs(&mut output, true);
+
+        let s = str::from_utf8(&output).unwrap();
+        assert_eq!(s.contains("newline_style"), true);
+        assert_eq!(s.contains("use_small_heuristics"), true);
+    }
+
     // FIXME(#2183) these tests cannot be run in parallel because they use env vars
     // #[test]
     // fn test_as_not_nightly_channel() {