Capture and log unknown fields from config file

CHANGELOG.md

@@ -16,6 +16,7 @@
 - Fixed issue where statements under top-level in-eachs were not correctly tracked.
 - Moved storage of reference->symbol mapping to on-demand timing, should significantly speed
   up device analysises
+- Unknown fields in the lint configuration file are now detected and reported as errors, helping users identify and correct typos or unsupported configuration options.
 - CLI tool DFA now uses default one-indexed line count for reporting warnings on analyzed files.
   `--zero-indexed` flag can be set to `true` when executing DFA for using zero-indexed counting if required.
 

src/actions/mod.rs

@@ -342,17 +342,14 @@ impl <O: Output> InitActionContext<O> {
         pid: u32,
         _client_supports_cmd_run: bool,
     ) -> InitActionContext<O> {
-        let lint_config = Arc::new(Mutex::new(
-            config.lock().unwrap().lint_cfg_path.clone()
-                .and_then(maybe_parse_lint_cfg)
-                .unwrap_or_default()));
+
         InitActionContext {
             vfs,
             analysis,
             analysis_queue: Arc::new(AnalysisQueue::init()),
             current_notifier: Arc::default(),
             config,
-            lint_config,
+            lint_config: Arc::new(Mutex::new(LintCfg::default())),
             jobs: Arc::default(),
             direct_opens: Arc::default(),
             quiescent: Arc::new(AtomicBool::new(false)),
@@ -388,7 +385,8 @@ impl <O: Output> InitActionContext<O> {
     fn init(&mut self,
             _init_options: InitializationOptions,
             out: O) {
-        self.update_compilation_info(&out)
+        self.update_compilation_info(&out);
+        self.update_linter_config(&out);
     }
 
     pub fn update_workspaces(&self,
@@ -401,13 +399,17 @@ impl <O: Output> InitActionContext<O> {
         }
     }
 
-    fn update_linter_config(&self, _out: &O) {
+    fn update_linter_config(&self, out: &O) {
         trace!("Updating linter config");
         if let Ok(config) = self.config.lock() {
-            *self.lint_config.lock().unwrap() =
-                config.lint_cfg_path.clone()
-                .and_then(maybe_parse_lint_cfg)
-                .unwrap_or_default();
+            if let Some(ref lint_path) = config.lint_cfg_path {
+                if let Some(cfg) = maybe_parse_lint_cfg(lint_path.clone(), out) {
+                    *self.lint_config.lock().unwrap() = cfg;
+                }
+            } else {
+                // If no lint config path is set, use default
+                *self.lint_config.lock().unwrap() = LintCfg::default();
+            }
         }
     }
 

src/actions/notifications.rs

@@ -249,6 +249,7 @@ impl BlockingNotificationAction for DidChangeWatchedFiles {
         if let Some(file_watch) = FileWatch::new(ctx) {
             if params.changes.iter().any(|c| file_watch.is_relevant(c)) {
                 ctx.update_compilation_info(&out);
+                ctx.update_linter_config(&out);
             }
         }
         Ok(())

src/lint/mod.rs

@@ -22,19 +22,27 @@ use crate::lint::rules::indentation::{MAX_LENGTH_DEFAULT,
                                       INDENTATION_LEVEL_DEFAULT,
                                       setup_indentation_size
                                     };
+use crate::server::{maybe_notify_unknown_lint_fields, Output};                                    
 
-pub fn parse_lint_cfg(path: PathBuf) -> Result<LintCfg, String> {
+pub fn parse_lint_cfg(path: PathBuf) -> Result<(LintCfg, Vec<String>), String> {
     debug!("Reading Lint configuration from {:?}", path);
-    let file_content = fs::read_to_string(path).map_err(
-        |e|e.to_string())?;
+    let file_content = fs::read_to_string(path).map_err(|e| e.to_string())?;
     trace!("Content is {:?}", file_content);
-    serde_json::from_str(&file_content)
-        .map_err(|e|e.to_string())
+
+    let val: serde_json::Value = serde_json::from_str(&file_content)
+        .map_err(|e| e.to_string())?;
+
+    let mut unknowns = Vec::new();
+    let cfg = LintCfg::try_deserialize(&val, &mut unknowns)?;
+
+    Ok((cfg, unknowns))
 }
 
-pub fn maybe_parse_lint_cfg(path: PathBuf) -> Option<LintCfg> {
+pub fn maybe_parse_lint_cfg<O: Output>(path: PathBuf, out: &O) -> Option<LintCfg> {
     match parse_lint_cfg(path) {
-        Ok(mut cfg) => {
+        Ok((mut cfg, unknowns)) => {
+            // Send visible warning to client
+            maybe_notify_unknown_lint_fields(out, &unknowns);
             setup_indentation_size(&mut cfg);
             Some(cfg)
         },
@@ -45,9 +53,10 @@ pub fn maybe_parse_lint_cfg(path: PathBuf) -> Option<LintCfg> {
     }
 }
 
+
+
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
 #[serde(default)]
-#[serde(deny_unknown_fields)]
 pub struct LintCfg {
     #[serde(default)]
     pub sp_brace: Option<SpBraceOptions>,
@@ -81,6 +90,21 @@ pub struct LintCfg {
     pub annotate_lints: bool,
 }
 
+impl LintCfg {
+    pub fn try_deserialize(
+        val: &serde_json::Value,
+        unknowns: &mut Vec<String>,
+    ) -> Result<LintCfg, String> {
+        // Use serde_ignored to automatically track unknown fields
+        match serde_ignored::deserialize(val, |json_field| {
+            unknowns.push(json_field.to_string());
+        }) {
+            Ok(cfg) => Ok(cfg),
+            Err(e) => Err(e.to_string()),
+        }
+    }
+}
+
 fn get_true() -> bool {
     true
 }
@@ -421,8 +445,47 @@ pub mod tests {
         let example_path = format!("{}{}",
                                    env!("CARGO_MANIFEST_DIR"),
                                    EXAMPLE_CFG);
-        let example_cfg = parse_lint_cfg(example_path.into()).unwrap();
+        let (example_cfg, unknowns) = parse_lint_cfg(example_path.into()).unwrap();
         assert_eq!(example_cfg, LintCfg::default());
+        // Assert that there are no unknown fields in the example config:
+        assert!(unknowns.is_empty(), "Example config should not have unknown fields: {:?}", unknowns);
+    }
+
+    #[test]
+    fn test_unknown_fields_detection() {
+        use crate::lint::LintCfg;
+
+        // JSON with unknown fields
+        let json_with_unknowns = r#"{
+            "sp_brace": {},
+            "unknown_field_1": true,
+            "indent_size": {"indentation_spaces": 4},
+            "another_unknown": "value"
+        }"#;
+
+        let val: serde_json::Value = serde_json::from_str(json_with_unknowns).unwrap();
+        let mut unknowns = Vec::new();
+        let result = LintCfg::try_deserialize(&val, &mut unknowns);
+
+        assert!(result.is_ok());
+        let cfg = result.unwrap();
+
+        // Assert that unknown fields were detected
+        assert_eq!(unknowns.len(), 2);
+        assert!(unknowns.contains(&"unknown_field_1".to_string()));
+        assert!(unknowns.contains(&"another_unknown".to_string()));
+
+        // Assert the final LintCfg matches expected json (the known fields)
+        let expected_json = r#"{
+            "sp_brace": {},
+            "indent_size": {"indentation_spaces": 4}
+        }"#;
+        let expected_val: serde_json::Value = serde_json::from_str(expected_json).unwrap();
+        let mut expected_unknowns = Vec::new();
+        let expected_cfg = LintCfg::try_deserialize(&expected_val, &mut expected_unknowns).unwrap();
+
+        assert_eq!(cfg, expected_cfg);
+        assert!(expected_unknowns.is_empty()); // No unknown fields in the expected config
     }
 
     #[test]

src/server/mod.rs

@@ -164,6 +164,22 @@ pub(crate) fn maybe_notify_deprecated_configs<O: Output>(out: &O, keys: &[String
     }
 }
 
+pub(crate) fn maybe_notify_unknown_lint_fields<O: Output>(out: &O, unknowns: &[String]) {
+    if !unknowns.is_empty() {
+        let fields_list = unknowns.join(", ");
+        let message = format!(
+            "Unknown lint configuration field{}: {}. These will be ignored.",
+            if unknowns.len() > 1 { "s" } else { "" },
+            fields_list
+        );
+
+        out.notify(Notification::<ShowMessage>::new(ShowMessageParams {
+            typ: MessageType::ERROR,
+            message,
+        }));
+    }
+}
+
 pub(crate) fn maybe_notify_duplicated_configs<O: Output>(
     out: &O,
     dups: &std::collections::HashMap<String, Vec<String>>,