fix(config): search for config file recursively on --config-path

src/config/mod.rs

@@ -354,50 +354,7 @@ impl Config {
         style_edition: Option<StyleEdition>,
         version: Option<Version>,
     ) -> Result<(Config, Option<PathBuf>), Error> {
-        /// Try to find a project file in the given directory and its parents.
-        /// Returns the path of the nearest project file if one exists,
-        /// or `None` if no project file was found.
-        fn resolve_project_file(dir: &Path) -> Result<Option<PathBuf>, Error> {
-            let mut current = if dir.is_relative() {
-                env::current_dir()?.join(dir)
-            } else {
-                dir.to_path_buf()
-            };
-
-            current = fs::canonicalize(current)?;
-
-            loop {
-                match get_toml_path(&current) {
-                    Ok(Some(path)) => return Ok(Some(path)),
-                    Err(e) => return Err(e),
-                    _ => (),
-                }
-
-                // If the current directory has no parent, we're done searching.
-                if !current.pop() {
-                    break;
-                }
-            }
-
-            // If nothing was found, check in the home directory.
-            if let Some(home_dir) = dirs::home_dir() {
-                if let Some(path) = get_toml_path(&home_dir)? {
-                    return Ok(Some(path));
-                }
-            }
-
-            // If none was found there either, check in the user's configuration directory.
-            if let Some(mut config_dir) = dirs::config_dir() {
-                config_dir.push("rustfmt");
-                if let Some(path) = get_toml_path(&config_dir)? {
-                    return Ok(Some(path));
-                }
-            }
-
-            Ok(None)
-        }
-
-        match resolve_project_file(dir)? {
+        match resolve_project_file(dir).or_else(|_| config_from_user_dirs())? {
             None => Ok((
                 Config::default_for_possible_style_edition(style_edition, edition, version),
                 None,
@@ -455,6 +412,53 @@ impl Config {
     }
 }
 
+/// Looks for a configuration file in the given directory and its parents.
+///
+/// Returns the path of the configuration file nearest to that directory if one exists, or `None` if
+/// none was found.
+fn resolve_project_file(dir: &Path) -> Result<Option<PathBuf>, Error> {
+    let mut current = if dir.is_relative() {
+        env::current_dir()?.join(dir)
+    } else {
+        dir.to_path_buf()
+    };
+
+    current = fs::canonicalize(current)?;
+
+    loop {
+        match get_toml_path(&current) {
+            Ok(Some(path)) => return Ok(Some(path)),
+            Err(e) => return Err(e),
+            _ => (),
+        }
+
+        // If the current directory has no parent, we're done searching.
+        if !current.pop() {
+            break Ok(None);
+        }
+    }
+}
+
+/// Looks for a configuration file in the user's home directory and configuration directory.
+///
+/// Returns the path of the first configuration file found in that order, or `None` if none was
+/// found.
+fn config_from_user_dirs() -> Result<Option<PathBuf>, Error> {
+    for dir in [
+        dirs::home_dir(),
+        dirs::config_dir().map(|d| d.join("rustfmt")),
+    ]
+    .iter()
+    .flatten()
+    {
+        if let Some(path) = get_toml_path(&dir)? {
+            return Ok(Some(path));
+        }
+    }
+
+    Ok(None)
+}
+
 /// Loads a config by checking the client-supplied options and if appropriate, the
 /// file system (including searching the file system for overrides).
 pub fn load_config<O: CliOptions>(
@@ -534,14 +538,7 @@ fn config_path(options: &dyn CliOptions) -> Result<Option<PathBuf>, Error> {
     // If a config file cannot be found from the given path, return error.
     match options.config_path() {
         Some(path) if !path.exists() => config_path_not_found(path.to_str().unwrap()),
-        Some(path) if path.is_dir() => {
-            let config_file_path = get_toml_path(path)?;
-            if config_file_path.is_some() {
-                Ok(config_file_path)
-            } else {
-                config_path_not_found(path.to_str().unwrap())
-            }
-        }
+        Some(path) if path.is_dir() => resolve_project_file(path),
         Some(path) => Ok(Some(
             // Canonicalize only after checking above that the `path.exists()`.
             path.canonicalize()?,

tests/config/issue_4660/Cargo.toml

@@ -0,0 +1,2 @@
+[workspace]
+members = ["inner_lib"]

tests/config/issue_4660/inner_bin/.rustfmt.unstable.toml

@@ -0,0 +1 @@
+disable_all_formatting = true

tests/config/issue_4660/inner_bin/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "inner_bin"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

tests/config/issue_4660/inner_bin/src/main.rs

@@ -0,0 +1 @@
+fn main(){println!("Hello, world!")}

tests/config/issue_4660/inner_lib/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "inner_lib"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

tests/config/issue_4660/inner_lib/rustfmt.toml

@@ -0,0 +1 @@
+disable_all_formatting = true

tests/config/issue_4660/inner_lib/src/lib.rs

@@ -0,0 +1 @@
+pub fn add(left:u64,right:u64)->u64{left+right}

tests/rustfmt/main.rs

@@ -345,6 +345,37 @@ fn rustfmt_error_improvement_regarding_invalid_toml() {
     assert!(stderr.contains(&expected_error_message));
 }
 
+#[test]
+fn config_path_walks_parent_directories_with_dir_name() {
+    let src_dir = "tests/config/issue_4660/inner_lib/src";
+    let src_file = src_dir.to_owned() + "/lib.rs";
+    let args = ["--config-path", src_dir, "--check", &src_file];
+    let (stdout, stderr) = rustfmt(&args);
+
+    assert_eq!(stderr, "");
+    // Due to `disable_all_formatting = true` in `tests/config/issue_4660/inner_lib/rustfmt.toml`,
+    // the source file should not be modified.
+    assert_eq!(stdout, "");
+}
+
+#[test]
+fn config_path_does_not_walk_parent_directories_with_toml_name() {
+    let src_dir = "tests/config/issue_4660/inner_bin/src";
+    let toml_file = src_dir.to_owned() + "/.rustfmt.unstable.toml";
+    let src_file = src_dir.to_owned() + "/main.rs";
+    let args = ["--config-path", &toml_file, "--check", &src_file];
+    let (stdout, stderr) = rustfmt(&args);
+
+    assert_eq!(
+        stderr,
+        format!(
+            "Error: unable to find a config file for the given path: `{}`\n",
+            Path::new(&toml_file).display(),
+        )
+    );
+    assert_eq!(stdout, "");
+}
+
 #[test]
 fn rustfmt_allow_not_a_dir_errors() {
     // See also https://github.com/rust-lang/rustfmt/pull/6624