fix: discover missed watch directories with snapshots

Author: aewing

packages/language-server/src/plugins/typescript/LSAndTSDocResolver.ts

@@ -46,6 +46,11 @@ interface LSAndTSDocResolverOptions {
     tsSystem?: ts.System;
     watchDirectory?: (patterns: RelativePattern[]) => void;
     nonRecursiveWatchPattern?: string;
+    /**
+     * Optional callback invoked when a new snapshot is created.
+     * Used by svelte-check to dynamically add parent directories to file watchers.
+     */
+    onSnapshotCreated?: (dirPath: string) => void;
 }
 
 export class LSAndTSDocResolver {
@@ -83,6 +88,20 @@ export class LSAndTSDocResolver {
 
         this.tsSystem = this.wrapWithPackageJsonMonitoring(this.options?.tsSystem ?? ts.sys);
         this.globalSnapshotsManager = new GlobalSnapshotsManager(this.tsSystem);
+        // Notify when new snapshots are created so external watchers (svelte-check)
+        // can add their parent directories dynamically.
+        if (this.options?.onSnapshotCreated) {
+            this.globalSnapshotsManager.onChange((fileName, newDocument) => {
+                if (newDocument) {
+                    try {
+                        const dir = dirname(fileName);
+                        this.options?.onSnapshotCreated?.(dir);
+                    } catch {
+                        // best-effort; ignore errors in callback
+                    }
+                }
+            });
+        }
         this.userPreferencesAccessor = { preferences: this.getTsUserPreferences() };
         const projectService = createProjectService(this.tsSystem, this.userPreferencesAccessor);
 

packages/language-server/src/svelte-check.ts

@@ -31,6 +31,11 @@ export interface SvelteCheckOptions {
     tsconfig?: string;
     onProjectReload?: () => void;
     watch?: boolean;
+    /**
+     * Optional callback invoked when a new snapshot is created.
+     * Used by svelte-check to dynamically add watch directories.
+     */
+    onSnapshotCreated?: (dirPath: string) => void;
 }
 
 /**
@@ -91,7 +96,8 @@ export class SvelteCheck {
                     tsconfigPath: options.tsconfig,
                     isSvelteCheck: true,
                     onProjectReloaded: options.onProjectReload,
-                    watch: options.watch
+                    watch: options.watch,
+                    onSnapshotCreated: options.onSnapshotCreated
                 }
             );
             this.pluginHost.register(

packages/svelte-check/src/index.ts

@@ -197,6 +197,16 @@ class DiagnosticsWatcher {
         this.updateWatchedDirectories();
     }
 
+    addWatchDirectory(dir: string) {
+        if (!dir || this.currentWatchedDirs.has(dir)) {
+            return;
+        }
+        this.watcher.add(dir);
+        this.currentWatchedDirs.add(dir);
+        // New files might now be visible; schedule a run
+        this.scheduleDiagnostics();
+    }
+
     private async updateWatchedDirectories() {
         const watchDirs = await this.svelteCheck.getWatchDirectories();
         const dirsToWatch = watchDirs || [{ path: this.workspaceUri.fsPath, recursive: true }];
@@ -303,11 +313,16 @@ parseOptions(async (opts) => {
         };
 
         if (opts.watch) {
+            // Wire callbacks that can reference the watcher instance created below
+            let watcher: DiagnosticsWatcher;
             svelteCheckOptions.onProjectReload = () => {
                 watcher.updateWatchers();
                 watcher.scheduleDiagnostics();
             };
-            const watcher = new DiagnosticsWatcher(
+            svelteCheckOptions.onSnapshotCreated = (dirPath: string) => {
+                watcher.addWatchDirectory(dirPath);
+            };
+            watcher = new DiagnosticsWatcher(
                 opts.workspaceUri,
                 new SvelteCheck(opts.workspaceUri.fsPath, svelteCheckOptions),
                 writer,