Improve error message for dependency without rescript.json

CHANGELOG.md

@@ -31,6 +31,8 @@
 
 #### :nail_care: Polish
 
+- Improve error message for dependency without `rescript.json`. https://github.com/rescript-lang/rescript/issues/8265
+
 #### :house: Internal
 
 - Reanalyze server: redesign incremental fixpoint with delete-then-rederive strategy and predecessor tracking, improving speed on deletions. https://github.com/rescript-lang/rescript/pull/8276

rewatch/src/build/packages.rs

@@ -352,7 +352,7 @@ fn read_dependencies(
 
                         let parent_path_str = project_context.get_root_path().to_string_lossy();
                         log::error!(
-                            "We could not build package tree reading dependency '{package_name}', at path '{parent_path_str}'. Error: {error}",
+                            "Could not build package tree reading dependency '{package_name}' at path '{parent_path_str}'. Error: {error}",
                         );
 
                         std::process::exit(2)
@@ -363,7 +363,7 @@ fn read_dependencies(
                             Err(error) => {
                                 let parent_path_str = project_context.get_root_path().to_string_lossy();
                                 log::error!(
-                                    "We could not build package tree  '{package_name}', at path '{parent_path_str}'. Error: {error}",
+                                    "Could not build package tree for '{package_name}' at path '{parent_path_str}'. Error: {error}",
                                 );
                                 std::process::exit(2)
                             }

rewatch/src/config.rs

@@ -450,7 +450,8 @@ fn namespace_from_package_name(package_name: &str) -> String {
 impl Config {
     /// Try to convert a config from a certain path to a config struct
     pub fn new(path: &Path) -> Result<Self> {
-        let read = fs::read_to_string(path)?;
+        let read =
+            fs::read_to_string(path).map_err(|e| anyhow!("Could not read '{}': {}", path.display(), e))?;
         let mut config = Config::new_from_json_string(&read)?;
         config.set_path(path.to_path_buf())?;
         Ok(config)
@@ -1490,4 +1491,14 @@ pub mod tests {
         let args = config.get_warning_args(false, Some("+3+8+11".to_string()));
         assert_eq!(args, Vec::<String>::new());
     }
+
+    #[test]
+    fn test_new_missing_rescript_json() {
+        let path = PathBuf::from("/nonexistent/path/rescript.json");
+        let error = Config::new(&path).unwrap_err().to_string();
+        assert!(
+            error.contains(path.to_string_lossy().as_ref()),
+            "Error should include the missing config path, got: {error}"
+        );
+    }
 }