feat(cli): add --config option

Author: JamieMason

src/cli.rs

@@ -37,6 +37,8 @@ pub enum UpdateTarget {
 pub struct Cli {
   /// Whether to check formatting instead of fixing it
   pub check: bool,
+  /// Path to a specific config file to use
+  pub config_path: Option<String>,
   /// The path to the root of the project
   pub cwd: PathBuf,
   /// Whether to disable ANSI color codes in terminal output
@@ -81,6 +83,7 @@ impl Cli {
     fn from_arg_matches(subcommand: Subcommand, matches: &ArgMatches) -> Cli {
       Cli {
         check: (matches!(&subcommand, Subcommand::Format | Subcommand::Update)) && matches.get_flag("check"),
+        config_path: matches.get_one::<String>("config").cloned(),
         cwd: env::current_dir().unwrap(),
         dependencies: get_patterns(matches, "dependencies"),
         dependency_types: get_patterns(matches, "dependency-types"),
@@ -144,6 +147,7 @@ fn create() -> Command {
       Command::new("lint")
         .about("Lint all versions and ranges and exit with 0 or 1 based on whether all files match your Syncpack configuration file")
         .after_long_help(additional_help())
+        .arg(config_option("lint"))
         .arg(dependencies_option("lint"))
         .arg(dependency_types_option("lint"))
         .arg(log_levels_option("lint"))
@@ -157,6 +161,7 @@ fn create() -> Command {
       Command::new("fix")
         .about("Ensure that multiple packages requiring the same dependency use the same version")
         .after_long_help(additional_help())
+        .arg(config_option("fix"))
         .arg(dependencies_option("fix"))
         .arg(dependency_types_option("fix"))
         .arg(dry_run_option("fix"))
@@ -177,6 +182,7 @@ fn create() -> Command {
             .long_help(cformat!(r#"Lint formatting instead of fixing it"#))
             .action(clap::ArgAction::SetTrue),
         )
+        .arg(config_option("format"))
         .arg(dry_run_option("format"))
         .arg(log_levels_option("format"))
         .arg(no_ansi_option("format"))
@@ -192,6 +198,7 @@ fn create() -> Command {
             .long_help(cformat!(r#"Check versions are up to date instead of updating them"#))
             .action(clap::ArgAction::SetTrue),
         )
+        .arg(config_option("update"))
         .arg(dependencies_option("update"))
         .arg(dependency_types_option("update"))
         .arg(dry_run_option("update"))
@@ -205,6 +212,7 @@ fn create() -> Command {
       Command::new("list")
         .about("Query and inspect all dependencies in your project, both valid and invalid")
         .after_long_help(additional_help())
+        .arg(config_option("list"))
         .arg(dependencies_option("list"))
         .arg(dependency_types_option("list"))
         .arg(log_levels_option("list"))
@@ -218,6 +226,7 @@ fn create() -> Command {
       Command::new("json")
         .about("Output all dependencies as flattened JSON objects")
         .after_long_help(additional_help())
+        .arg(config_option("json"))
         .arg(dependencies_option("json"))
         .arg(dependency_types_option("json"))
         .arg(log_levels_option("json"))
@@ -228,6 +237,12 @@ fn create() -> Command {
     )
 }
 
+fn config_option(_command: &str) -> Arg {
+  Arg::new("config").long("config").value_name("PATH").long_help(cformat!(
+    r#"Path to a specific config file to use. When set, config file discovery is skipped."#
+  ))
+}
+
 fn dependencies_option(command: &str) -> Arg {
   let short_help = "Only include dependencies whose name matches this glob pattern";
   Arg::new("dependencies")

src/rcfile/discovery.rs

@@ -2,18 +2,23 @@ use {
   crate::{
     cli::Cli,
     rcfile::{
-      javascript::try_from_js_candidates, json::try_from_json_candidates, package_json::try_from_package_json_config_property,
-      yaml::try_from_yaml_candidates, Rcfile,
+      error::RcfileError,
+      javascript::{from_javascript_path, try_from_js_candidates},
+      json::{from_json_path, try_from_json_candidates},
+      package_json::try_from_package_json_config_property,
+      yaml::{from_yaml_path, try_from_yaml_candidates},
+      Rcfile,
     },
   },
   log::{debug, error},
-  std::{process::exit, time::Instant},
+  std::{path::PathBuf, process::exit, time::Instant},
 };
 
 impl Rcfile {
   pub fn from_disk(cli: &Cli) -> Rcfile {
     let start = Instant::now();
-    let rcfile = try_from_json_candidates(cli)
+    let rcfile = Self::try_from_cli_option(cli)
+      .or_else(|| try_from_json_candidates(cli))
       .or_else(|| try_from_yaml_candidates(cli))
       .or_else(|| try_from_package_json_config_property(cli))
       .or_else(|| try_from_js_candidates(cli))
@@ -31,4 +36,32 @@ impl Rcfile {
     debug!("Config discovery completed in {:?}", start.elapsed());
     rcfile
   }
+
+  fn try_from_cli_option(cli: &Cli) -> Option<Result<Rcfile, RcfileError>> {
+    cli.config_path.as_ref().map(|path| {
+      let config_path = PathBuf::from(path);
+      let absolute_path = if config_path.is_absolute() {
+        config_path
+      } else {
+        cli.cwd.join(config_path)
+      };
+
+      debug!("Using config file from CLI option: {absolute_path:?}");
+
+      if !absolute_path.exists() {
+        return Err(RcfileError::FileReadFailed(std::io::Error::new(
+          std::io::ErrorKind::NotFound,
+          format!("Config file not found: {}", absolute_path.display()),
+        )));
+      }
+
+      let extension = absolute_path.extension().and_then(|ext| ext.to_str());
+      match extension {
+        Some("json") => from_json_path(&absolute_path),
+        Some("yaml") | Some("yml") => from_yaml_path(&absolute_path),
+        Some("js") | Some("cjs") | Some("mjs") | Some("ts") | Some("cts") | Some("mts") => from_javascript_path(&absolute_path),
+        _ => from_json_path(&absolute_path),
+      }
+    })
+  }
 }

src/test/mock.rs

@@ -17,6 +17,7 @@ use {
 pub fn cli() -> Cli {
   Cli {
     check: true,
+    config_path: None,
     cwd: env::current_dir().unwrap(),
     dependencies: vec![],
     dependency_types: vec![],