Don’t make conf errors fatal errors

src/lib.rs

@@ -111,24 +111,30 @@ mod reexport {
 #[plugin_registrar]
 #[cfg_attr(rustfmt, rustfmt_skip)]
 pub fn plugin_registrar(reg: &mut Registry) {
-    let conferr = match utils::conf::conf_file(reg.args()) {
-        Ok(Some(file_name)) => {
-            utils::conf::read_conf(&file_name, true)
-        }
-        Ok(None) => {
-            utils::conf::read_conf("Clippy.toml", false)
-        }
-        Err((err, span)) => {
-            reg.sess.struct_span_err(span, err).emit();
-            return;
-        }
+    let conf = match utils::conf::conf_file(reg.args()) {
+        Ok(file_name) => {
+            // if the user specified a file, it must exist, otherwise default to `Clippy.toml` but
+            // do not require the file to exist
+            let (ref file_name, must_exist) = if let Some(ref file_name) = file_name {
+                (&**file_name, true)
+            } else {
+                ("Clippy.toml", false)
             };
 
-    let conf = match conferr {
-        Ok(conf) => conf,
-        Err(err) => {
-            reg.sess.struct_err(&format!("error reading Clippy's configuration file: {}", err)).emit();
-            return;
+            let (conf, errors) = utils::conf::read_conf(&file_name, must_exist);
+
+            // all conf errors are non-fatal, we just use the default conf in case of error
+            for error in errors {
+                reg.sess.struct_err(&format!("error reading Clippy's configuration file: {}", error)).emit();
+            }
+
+            conf
+        }
+        Err((err, span)) => {
+            reg.sess.struct_span_err(span, err)
+                    .span_note(span, "Clippy will use defaulf configuration")
+                    .emit();
+            utils::conf::Conf::default()
         }
     };
 

src/utils/conf.rs

@@ -157,20 +157,28 @@ define_Conf! {
 
 /// Read the `toml` configuration file. The function will ignore “File not found” errors iif
 /// `!must_exist`, in which case, it will return the default configuration.
-pub fn read_conf(path: &str, must_exist: bool) -> Result<Conf, ConfError> {
+/// In case of error, the function tries to continue as much as possible.
+pub fn read_conf(path: &str, must_exist: bool) -> (Conf, Vec<ConfError>) {
     let mut conf = Conf::default();
+    let mut errors = Vec::new();
 
     let file = match fs::File::open(path) {
         Ok(mut file) => {
             let mut buf = String::new();
-            try!(file.read_to_string(&mut buf));
+
+            if let Err(err) = file.read_to_string(&mut buf) {
+                errors.push(err.into());
+                return (conf, errors);
+            }
+
             buf
         }
         Err(ref err) if !must_exist && err.kind() == io::ErrorKind::NotFound => {
-            return Ok(conf);
+            return (conf, errors);
         }
         Err(err) => {
-            return Err(err.into());
+            errors.push(err.into());
+            return (conf, errors);
         }
     };
 
@@ -178,12 +186,15 @@ pub fn read_conf(path: &str, must_exist: bool) -> Result<Conf, ConfError> {
     let toml = if let Some(toml) = parser.parse() {
         toml
     } else {
-        return Err(ConfError::TomlError(parser.errors));
+        errors.push(ConfError::TomlError(parser.errors));
+        return (conf, errors);
     };
 
     for (key, value) in toml {
-        try!(conf.set(key, value));
+        if let Err(err) = conf.set(key, value) {
+            errors.push(err);
+        }
     }
 
-    Ok(conf)
+    (conf, errors)
 }