Fix config file lookup

Author: camsteffen

clippy_lints/src/lib.rs

@@ -405,7 +405,6 @@ pub fn register_pre_expansion_lints(store: &mut rustc_lint::LintStore) {
 
 #[doc(hidden)]
 pub fn read_conf(sess: &Session) -> Conf {
-    use std::path::Path;
     let file_name = match utils::conf::lookup_conf_file() {
         Ok(Some(path)) => path,
         Ok(None) => return Conf::default(),
@@ -416,16 +415,6 @@ pub fn read_conf(sess: &Session) -> Conf {
         },
     };
 
-    let file_name = if file_name.is_relative() {
-        sess.local_crate_source_file
-            .as_deref()
-            .and_then(Path::parent)
-            .unwrap_or_else(|| Path::new(""))
-            .join(file_name)
-    } else {
-        file_name
-    };
-
     let TryConf { conf, errors } = utils::conf::read(&file_name);
     // all conf errors are non-fatal, we just use the default conf in case of error
     for error in errors {

clippy_lints/src/utils/conf.rs

@@ -210,15 +210,13 @@ pub fn lookup_conf_file() -> io::Result<Option<PathBuf>> {
         .map_or_else(|| PathBuf::from("."), PathBuf::from);
     loop {
         for config_file_name in &CONFIG_FILE_NAMES {
-            let config_file = current.join(config_file_name);
-            match fs::metadata(&config_file) {
-                // Only return if it's a file to handle the unlikely situation of a directory named
-                // `clippy.toml`.
-                Ok(ref md) if !md.is_dir() => return Ok(Some(config_file)),
-                // Return the error if it's something other than `NotFound`; otherwise we didn't
-                // find the project file yet, and continue searching.
-                Err(e) if e.kind() != io::ErrorKind::NotFound => return Err(e),
-                _ => {},
+            if let Ok(config_file) = current.join(config_file_name).canonicalize() {
+                match fs::metadata(&config_file) {
+                    Err(e) if e.kind() == io::ErrorKind::NotFound => {},
+                    Err(e) => return Err(e),
+                    Ok(md) if md.is_dir() => {},
+                    Ok(_) => return Ok(Some(config_file)),
+                }
             }
         }