fix(config): lower the priority of global configuration file (#51)

git-cliff-core/src/config.rs

@@ -1,5 +1,6 @@
 use crate::error::Result;
 use regex::Regex;
+use std::path::Path;
 
 /// Configuration values.
 #[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
@@ -83,10 +84,10 @@ pub struct LinkParser {
 
 impl Config {
 	/// Parses the config file and returns the values.
-	pub fn parse(file_name: String) -> Result<Config> {
+	pub fn parse(path: &Path) -> Result<Config> {
 		let mut config = config::Config::default();
 		config
-			.merge(config::File::with_name(&file_name))?
+			.merge(config::File::from(path))?
 			.merge(config::Environment::with_prefix("CLIFF").separator("_"))?;
 		Ok(config.try_into()?)
 	}
@@ -100,17 +101,14 @@ mod test {
 	use std::path::PathBuf;
 	#[test]
 	fn parse_config() -> Result<()> {
-		let file_name = PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+		let path = PathBuf::from(env!("CARGO_MANIFEST_DIR"))
 			.parent()
 			.unwrap()
 			.to_path_buf()
 			.join("config")
-			.join(crate::DEFAULT_CONFIG)
-			.to_str()
-			.unwrap()
-			.to_string();
+			.join(crate::DEFAULT_CONFIG);
 		env::set_var("CLIFF_CHANGELOG_FOOTER", "test");
-		let config = Config::parse(file_name)?;
+		let config = Config::parse(&path)?;
 		assert_eq!("test", config.changelog.footer.unwrap());
 		Ok(())
 	}

git-cliff/src/lib.rs

@@ -52,27 +52,23 @@ pub fn run(mut args: Opt) -> Result<()> {
 	}
 
 	// Parse the configuration file.
-	let mut path = match args.config.to_str() {
-		Some(v) => Ok(v.to_string()),
-		None => Err(Error::IoError(io::Error::new(
-			io::ErrorKind::Other,
-			"path contains invalid characters",
-		))),
-	}?;
-	if let Some(config_path) = dirs_next::config_dir()
-		.map(|dir| dir.join(env!("CARGO_PKG_NAME")).join(DEFAULT_CONFIG))
-		.and_then(|path| path.to_str().map(String::from))
-	{
-		if fs::metadata(&config_path).is_ok() {
+	let mut path = args.config.clone();
+	if !path.exists() {
+		if let Some(config_path) = dirs_next::config_dir()
+			.map(|dir| dir.join(env!("CARGO_PKG_NAME")).join(DEFAULT_CONFIG))
+		{
 			path = config_path;
 		}
 	}
 
 	// Load the default configuration if necessary.
-	let mut config = if fs::metadata(&path).is_ok() {
-		Config::parse(path)?
+	let mut config = if path.exists() {
+		Config::parse(&path)?
 	} else {
-		warn!("{:?} is not found, using the default configuration.", path);
+		warn!(
+			"{:?} is not found, using the default configuration.",
+			args.config
+		);
 		EmbeddedConfig::parse()?
 	};
 	if config.changelog.body.is_none() {