feat(cli): add --print-default-config and -c/--config with presets and tilde expansion

src/app.rs

@@ -17,10 +17,11 @@ impl App {
     pub fn new(
         repo_path: PathBuf,
         debug: bool,
+        config_override: Option<String>,
         filter_path: Option<PathBuf>,
         start_in_commits: bool,
     ) -> Result<Self> {
-        let config = AppConfig::load(debug)?;
+        let config = AppConfig::load(debug, config_override)?;
 
         // Validate git repo
         if !GitCommands::is_valid_repo(&repo_path) {

src/config/mod.rs

@@ -46,12 +46,12 @@ impl Default for AppConfig {
 }
 
 impl AppConfig {
-    pub fn load(debug: bool) -> Result<Self> {
+    pub fn load(debug: bool, config_override: Option<String>) -> Result<Self> {
         let home_dir = dirs::home_dir().unwrap_or_else(|| PathBuf::from("."));
         let candidates = config_dir_candidates();
-        let config_dir = candidates
+        let mut config_dir = candidates
             .iter()
-            .find(|dir| dir.join("config.yml").exists())
+            .find(|dir| dir.join("config.yml").exists() || dir.join("config.yaml").exists())
             .cloned()
             .unwrap_or_else(|| candidates[0].clone());
 
@@ -71,7 +71,19 @@ impl AppConfig {
             let _ = std::fs::copy(&legacy_state_path, &state_path);
         }
 
-        let user_config = UserConfig::load(&config_dir)?;
+        let user_config = UserConfig::load(&config_dir, config_override.as_ref())?;
+        if let Some(ref over) = config_override {
+            let over_path = user_config::expand_tilde(over);
+            if let Some(parent) = over_path.parent() {
+                if over_path.is_absolute()
+                    || over.ends_with(".yml")
+                    || over.ends_with(".yaml")
+                    || over_path.exists()
+                {
+                    config_dir = parent.to_path_buf();
+                }
+            }
+        }
         let app_state = AppState::load(&state_path)?;
 
         Ok(Self {

src/config/user_config.rs

@@ -52,9 +52,58 @@ impl Default for RefresherConfig {
     }
 }
 
+pub(crate) fn expand_tilde(path_str: &str) -> std::path::PathBuf {
+    if let Some(stripped) = path_str.strip_prefix("~/") {
+        if let Some(home) = dirs::home_dir() {
+            return home.join(stripped);
+        }
+    } else if path_str == "~" {
+        if let Some(home) = dirs::home_dir() {
+            return home;
+        }
+    }
+    std::path::PathBuf::from(path_str)
+}
+
 impl UserConfig {
-    pub fn load(config_dir: &Path) -> Result<Self> {
-        let config_path = config_dir.join("config.yml");
+    pub fn load(config_dir: &Path, config_override: Option<&String>) -> Result<Self> {
+        let mut config_path = if config_dir.join("config.yml").exists() {
+            config_dir.join("config.yml")
+        } else if config_dir.join("config.yaml").exists() {
+            config_dir.join("config.yaml")
+        } else {
+            config_dir.join("config.yml")
+        };
+
+        if let Some(over) = config_override {
+            let expanded_path = expand_tilde(over);
+            if expanded_path.is_absolute()
+                || over.ends_with(".yml")
+                || over.ends_with(".yaml")
+                || expanded_path.exists()
+            {
+                config_path = expanded_path;
+            } else {
+                let preset_yaml = config_dir.join("presets").join(format!("{}.yaml", over));
+                let preset_yml = config_dir.join("presets").join(format!("{}.yml", over));
+                if preset_yaml.exists() {
+                    config_path = preset_yaml;
+                } else if preset_yml.exists() {
+                    config_path = preset_yml;
+                } else {
+                    anyhow::bail!(
+                        "Config file or preset not found: '{}' (checked relative, absolute, and presets in {})",
+                        over,
+                        config_dir.display()
+                    );
+                }
+            }
+
+            if !config_path.exists() {
+                anyhow::bail!("Config file not found at: {}", config_path.display());
+            }
+        }
+
         if config_path.exists() {
             let contents = std::fs::read_to_string(&config_path)?;
             let config: UserConfig = serde_yaml::from_str(&contents)?;
@@ -629,3 +678,26 @@ pub struct CustomCommandPrompt {
     pub command: Option<String>,
     pub filter: Option<String>,
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_expand_tilde() {
+        let expanded = expand_tilde("~/test/path");
+        if let Some(home) = dirs::home_dir() {
+            assert_eq!(expanded, home.join("test/path"));
+        }
+    }
+
+    #[test]
+    fn test_load_nonexistent_override_fails() {
+        let temp_dir = std::env::temp_dir();
+        let result = UserConfig::load(
+            &temp_dir,
+            Some(&"/path/that/does/not/exist/definitely/config.yml".to_string()),
+        );
+        assert!(result.is_err());
+    }
+}

src/main.rs

@@ -39,6 +39,14 @@ struct Cli {
     #[arg(short = 'f', long = "filter", value_name = "PATH")]
     filter_path: Option<PathBuf>,
 
+    /// Print the default configuration YAML to stdout and exit
+    #[arg(long)]
+    print_default_config: bool,
+
+    /// Configuration file or preset name to use (e.g. 'popup' or ~/.config/lazygitrs/config.yml)
+    #[arg(short = 'c', long = "config")]
+    config: Option<String>,
+
     /// Launch directly in the commits panel
     #[arg(long)]
     commits: bool,
@@ -106,6 +114,13 @@ fn main() {
         return;
     }
 
+    if cli.print_default_config {
+        let config = config::user_config::UserConfig::default();
+        let yaml = serde_yaml::to_string(&config).unwrap();
+        println!("{}", yaml);
+        std::process::exit(0);
+    }
+
     // Set up logging if debug mode
     if cli.debug {
         tracing_subscriber::fmt()
@@ -119,7 +134,13 @@ fn main() {
         .or(cli.work_tree)
         .unwrap_or_else(|| std::env::current_dir().unwrap_or_else(|_| PathBuf::from(".")));
 
-    match app::App::new(repo_path, cli.debug, cli.filter_path, cli.commits) {
+    match app::App::new(
+        repo_path,
+        cli.debug,
+        cli.config,
+        cli.filter_path,
+        cli.commits,
+    ) {
         Ok(app) => {
             if let Err(e) = app.run() {
                 eprintln!("Error: {:#}", e);
@@ -145,4 +166,22 @@ mod tests {
         let cli_default = Cli::parse_from(["lazygitrs"]);
         assert!(!cli_default.commits);
     }
+
+    #[test]
+    fn test_cli_config_flag() {
+        let cli = Cli::parse_from(["lazygitrs", "-c", "my-config.yml"]);
+        assert_eq!(cli.config.as_deref(), Some("my-config.yml"));
+
+        let cli_long = Cli::parse_from(["lazygitrs", "--config", "popup"]);
+        assert_eq!(cli_long.config.as_deref(), Some("popup"));
+
+        let cli_default = Cli::parse_from(["lazygitrs"]);
+        assert_eq!(cli_default.config, None);
+    }
+
+    #[test]
+    fn test_cli_print_default_config_flag() {
+        let cli = Cli::parse_from(["lazygitrs", "--print-default-config"]);
+        assert!(cli.print_default_config);
+    }
 }