liquid-java · rcosta358 · May 28, 2026 · May 28, 2026
diff --git a/client/src/lsp/client.ts b/client/src/lsp/client.ts
@@ -3,7 +3,7 @@ import { LanguageClient, LanguageClientOptions, ServerOptions } from 'vscode-lan
 import { connectToPort } from '../utils/utils';
 import { extension } from '../state';
 import { updateStatusBar } from '../services/status-bar';
-import { handleLJDiagnostics } from '../services/diagnostics';
+import { handleLJDiagnostics, handleLJFailure } from '../services/diagnostics';
 import { onActiveFileChange } from '../services/events';
 import type { LJDiagnostic } from "../types/diagnostics";
 import { LJContext } from '../types/context';
@@ -42,6 +42,10 @@ export async function runClient(context: vscode.ExtensionContext, port: number)
             handleLJDiagnostics(diagnostics);
         });
 
+        extension.client.onNotification("liquidjava/failure", () => {
+            handleLJFailure();
+        });
+
         extension.client.onNotification("liquidjava/context", (context: LJContext) => {
             handleContext(context);
         });

diff --git a/client/src/services/diagnostics.ts b/client/src/services/diagnostics.ts
@@ -1,7 +1,7 @@
 import * as vscode from "vscode";
-import { extension } from "../state";
+import { extension, ExtensionStatus } from "../state";
 import { LJDiagnostic } from "../types/diagnostics";
-import { StatusBarState, updateStatusBar } from "./status-bar";
+import { updateStatusBar } from "./status-bar";
 import { updateErrorAtCursor } from "./context";
 import { refreshCodeLenses } from "./codelens";
 
@@ -11,7 +11,7 @@ import { refreshCodeLenses } from "./codelens";
  */
 export function handleLJDiagnostics(diagnostics: LJDiagnostic[]) {
     const containsError = diagnostics.some(d => d.category === "error");
-    const statusBarState: StatusBarState = containsError ? "failed" : "passed";
+    const statusBarState: ExtensionStatus = containsError ? "failed" : "passed";
     updateStatusBar(statusBarState);
     extension.diagnostics = diagnostics;
     refreshCodeLenses();
@@ -21,6 +21,19 @@ export function handleLJDiagnostics(diagnostics: LJDiagnostic[]) {
         extension.webview?.sendMessage({ type: "context", context: extension.context, errorAtCursor: extension.errorAtCursor });
 }
 
+/**
+ * Handles LiquidJava verifier crashes received from the language server
+ */
+export function handleLJFailure() {
+    extension.diagnostics = [];
+    extension.errorAtCursor = undefined;
+    refreshCodeLenses();
+    extension.webview?.sendMessage({ type: "diagnostics", diagnostics: [] });
+    if (extension.context)
+        extension.webview?.sendMessage({ type: "context", context: extension.context, errorAtCursor: extension.errorAtCursor });
+    updateStatusBar("crashed");
+}
+
 /**
  * Triggers the LiquidJava verification manually
  */

diff --git a/client/src/services/status-bar.ts b/client/src/services/status-bar.ts
@@ -1,20 +1,20 @@
 import * as vscode from "vscode";
 import { ExtensionStatus, extension } from "../state";
 
-export type StatusBarState = ExtensionStatus;
-
- const icons = {
+const icons = {
     loading: "$(sync~spin)",
     stopped: "$(circle-slash)",
     passed: "$(check)",
     failed: "$(x)",
+    crashed: "$(x)",
 };
 
 const statusText = {
     loading: "Loading",
     stopped: "Stopped",
     passed: "Verification passed",
     failed: "Verification failed",
+    crashed: "Crashed",
 };
 
 /**
@@ -31,15 +31,15 @@ export function registerStatusBar(context: vscode.ExtensionContext) {
 
 /**
  * Updates the status bar with the current state
- * @param status The current status ("loading", "stopped", "passed", "failed")
+ * @param status The current status ("loading", "stopped", "passed", "failed", "crashed")
  * @param notifyWebview Whether the webview should reflect this status update.
  */
-export function updateStatusBar(status: StatusBarState, notifyWebview = status !== "loading") {
+export function updateStatusBar(status: ExtensionStatus, notifyWebview = status !== "loading") {
     if (notifyWebview) {
         extension.status = status;
         extension.webview?.sendMessage({ type: "status", status });
     }
-    const color = status === "stopped" ? "errorForeground" : "statusBar.foreground";
+    const color = status === "stopped" || status === "crashed" ? "errorForeground" : "statusBar.foreground";
     if (!extension.statusBar) return;
     extension.statusBar.color = new vscode.ThemeColor(color);
     extension.statusBar.text = icons[status] + " LiquidJava";

diff --git a/client/src/services/webview.ts b/client/src/services/webview.ts
@@ -25,11 +25,11 @@ export function registerWebview(context: vscode.ExtensionContext) {
     context.subscriptions.push(
         extension.webview.onDidReceiveMessage(message => {
             if (message.type === "ready") {
-                if (extension.status) extension.webview?.sendMessage({ type: "status", status: extension.status });
                 if (extension.file) extension.webview?.sendMessage({ type: "file", file: extension.file });
                 if (extension.diagnostics) extension.webview?.sendMessage({ type: "diagnostics", diagnostics: extension.diagnostics });
                 if (extension.context) extension.webview?.sendMessage({ type: "context", context: extension.context , errorAtCursor: extension.errorAtCursor });
                 if (extension.stateMachine) extension.webview?.sendMessage({ type: "fsm", sm: extension.stateMachine });
+                if (extension.status) extension.webview?.sendMessage({ type: "status", status: extension.status });
             }
         })
     );

diff --git a/client/src/state.ts b/client/src/state.ts
@@ -8,7 +8,7 @@ import type { LJDiagnostic, RefinementMismatchError } from "./types/diagnostics"
 import type { LJStateMachine } from "./types/fsm";
 import { LJContext, Range } from "./types/context";
 
-export type ExtensionStatus = "loading" | "stopped" | "passed" | "failed";
+export type ExtensionStatus = "loading" | "stopped" | "passed" | "failed" | "crashed";
 
 export class ExtensionState {
     // server/client state

diff --git a/client/src/webview/script.ts b/client/src/webview/script.ts
@@ -304,9 +304,9 @@ export function getScript(vscode: VSCodeApi, document: Document, window: Window)
      * Updates the webview content based on the current state
      */
     function updateView() {
-        if (status === 'stopped') {
+        if (status === 'stopped' || status === 'crashed') {
             currentDiagram = '';
-            root.innerHTML = renderStopped();
+            root.innerHTML = renderStopped(status);
             return;
         }
         if (status === 'loading') {

diff --git a/client/src/webview/styles.ts b/client/src/webview/styles.ts
@@ -437,6 +437,7 @@ export function getStyles(): string {
         }
         .stopped-view {
             display: flex;
+            position: relative;
             min-height: calc(100vh - 2rem);
             flex-direction: column;
             align-items: center;

diff --git a/client/src/webview/views/stopped.ts b/client/src/webview/views/stopped.ts
@@ -1,9 +1,23 @@
-export function renderStopped(): string {
+type StoppedViewStatus = "stopped" | "crashed";
+
+const stoppedViewContent: Record<StoppedViewStatus, { title: string; message: string }> = {
+    stopped: {
+        title: "LiquidJava Not Running",
+        message: /*html*/`To use LiquidJava, run <code>LiquidJava: Start</code> from the command palette.`,
+    },
+    crashed: {
+        title: "LiquidJava Crashed",
+        message: /*html*/`LiquidJava could not verify this project. <br /> Check for Java compilation errors.<br /><br />To inspect the problem, run <code>LiquidJava: Show Logs</code> from the command palette.`,
+    },
+};
+
+export function renderStopped(status: StoppedViewStatus): string {
+    const { title, message } = stoppedViewContent[status];
     return /*html*/`
         <div class="stopped-view">
             <div class="stopped-status-icon" aria-hidden="true">!</div>
-            <h2>LiquidJava Not Running</h2>
-            <p class="info">To use LiquidJava, run <code>LiquidJava: Start</code> from the command palette</p>
+            <h2>${title}</h2>
+            <p class="info">${message}</p>
         </div>
     `;
 }
diff --git a/server/src/main/java/LJDiagnosticsHandler.java b/server/src/main/java/LJDiagnosticsHandler.java
@@ -14,7 +14,6 @@
 import liquidjava.api.CommandLineLauncher;
 import liquidjava.diagnostics.Diagnostics;
 import liquidjava.diagnostics.LJDiagnostic;
-import liquidjava.diagnostics.errors.CustomError;
 import liquidjava.diagnostics.errors.LJError;
 import liquidjava.diagnostics.warnings.LJWarning;
 import spoon.reflect.cu.SourcePosition;
@@ -29,28 +28,23 @@ public class LJDiagnosticsHandler {
      * @param path the file path
      * @return LJDiagnostics
      */
-    public static LJDiagnostics getLJDiagnostics(String path) {
+    public static LJDiagnostics getLJDiagnostics(String path) throws Exception {
         List<LJError> errors = new ArrayList<>();
         List<LJWarning> warnings = new ArrayList<>();
-        try {
-            CommandLineLauncher.cmdArgs.lspMode = true;
-            CommandLineLauncher.launch(path);
-            Diagnostics diagnostics = Diagnostics.getInstance();
-            if (diagnostics.foundWarning()) {
-                warnings.addAll(diagnostics.getWarnings());
-            }
-            if (diagnostics.foundError()) {
-                System.out.println("Failed verification");
-                errors.addAll(diagnostics.getErrors());
-            } else {
-                System.out.println("Passed verification");
-            }
-            return new LJDiagnostics(errors, warnings);
-        } catch (Exception e) {
-            e.printStackTrace();
-            errors.add(new CustomError("LiquidJava verification failed, check for Java errors"));
-            return new LJDiagnostics(errors, warnings);
+
+        CommandLineLauncher.cmdArgs.lspMode = true;
+        CommandLineLauncher.launch(path);
+        Diagnostics diagnostics = Diagnostics.getInstance();
+        if (diagnostics.foundWarning()) {
+            warnings.addAll(diagnostics.getWarnings());
+        }
+        if (diagnostics.foundError()) {
+            System.out.println("Failed verification");
+            errors.addAll(diagnostics.getErrors());
+        } else {
+            System.out.println("Passed verification");
         }
+        return new LJDiagnostics(errors, warnings);
     }
 
     /**

diff --git a/server/src/main/java/LJDiagnosticsService.java b/server/src/main/java/LJDiagnosticsService.java
@@ -1,6 +1,8 @@
 import java.io.File;
 import java.net.URI;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
@@ -27,6 +29,7 @@ public class LJDiagnosticsService implements TextDocumentService, WorkspaceServi
 
     private LJLanguageClient client;
     private String workspaceRoot;
+    private final Set<String> publishedDiagnosticUris = new HashSet<>();
     private final ExecutorService diagnosticsExecutor = Executors.newSingleThreadExecutor(r -> {
         Thread thread = new Thread(r, "liquidjava-diagnostics");
         thread.setDaemon(true);
@@ -61,14 +64,26 @@ public void sendDiagnosticsNotification(List<LJDiagnostic> diagnostics) {
      */
     public void generateDiagnostics(String uri) {
         String path = PathUtils.extractBasePath(uri);
-        LJDiagnostics ljDiagnostics = LJDiagnosticsHandler.getLJDiagnostics(path);
-        List<PublishDiagnosticsParams> nativeDiagnostics = LJDiagnosticsHandler.getNativeDiagnostics(ljDiagnostics, uri);
-        nativeDiagnostics.forEach(params -> {
-            this.client.publishDiagnostics(params);
-        });
-        List<LJDiagnostic> diagnostics = Stream.concat(ljDiagnostics.errors().stream(), ljDiagnostics.warnings().stream()).collect(Collectors.toList());
-        sendDiagnosticsNotification(diagnostics);
-        this.client.sendContext(ContextHistoryConverter.convertToDTO(ContextHistory.getInstance()));
+        clearPublishedDiagnostics(uri);
+
+        try {
+            LJDiagnostics ljDiagnostics = LJDiagnosticsHandler.getLJDiagnostics(path);
+            List<PublishDiagnosticsParams> nativeDiagnostics = LJDiagnosticsHandler.getNativeDiagnostics(ljDiagnostics, uri);
+            nativeDiagnostics.forEach(params -> {
+                this.client.publishDiagnostics(params);
+                if (!params.getDiagnostics().isEmpty()) {
+                    publishedDiagnosticUris.add(params.getUri());
+                }
+            });
+            List<LJDiagnostic> diagnostics = Stream.concat(ljDiagnostics.errors().stream(), ljDiagnostics.warnings().stream()).collect(Collectors.toList());
+            sendDiagnosticsNotification(diagnostics);
+            this.client.sendContext(ContextHistoryConverter.convertToDTO(ContextHistory.getInstance()));
+        } catch (Exception e) {
+            System.err.println("LiquidJava verification crashed while checking: " + path);
+            e.printStackTrace(System.err);
+            clearPublishedDiagnostics(uri);
+            this.client.sendFailure();
+        }
     }
 
     /**
@@ -93,10 +108,18 @@ public void shutdown() {
      */
     public void clearDiagnostic(String uri) {
         this.client.publishDiagnostics(LJDiagnosticsHandler.getEmptyDiagnostics(uri));
+        publishedDiagnosticUris.remove(uri);
         // TODO: fix consistency between native and custom diagnostics
         // sendDiagnosticsNotification(List.of());
     }
 
+    private void clearPublishedDiagnostics(String uri) {
+        Set<String> urisToClear = new HashSet<>(publishedDiagnosticUris);
+        urisToClear.add(uri);
+        urisToClear.forEach(clearUri -> this.client.publishDiagnostics(LJDiagnosticsHandler.getEmptyDiagnostics(clearUri)));
+        publishedDiagnosticUris.clear();
+    }
+
     /**
      * Checks diagnostics when a document is opened
      * @param params

diff --git a/server/src/main/java/LJLanguageClient.java b/server/src/main/java/LJLanguageClient.java
@@ -18,6 +18,12 @@ public interface LJLanguageClient extends LanguageClient {
     @JsonNotification("liquidjava/diagnostics")
     void sendDiagnostics(List<Object> diagnostics);
 
+    /**
+     * Sends a verifier failure notification to the client
+     */
+    @JsonNotification("liquidjava/failure")
+    void sendFailure();
+
     /**
      * Sends the context history to the client
      * @param contextHistory the context history to send