Rebuild a theme graph that failed to build

.changeset/graph-rebuild-after-error.md

@@ -0,0 +1,5 @@
+---
+'@shopify/theme-language-server-common': patch
+---
+
+Rebuild a theme graph that failed to build when a file changes. Before, the failed graph stayed until the language server restarted.

packages/theme-language-server-common/src/server/ThemeGraphManager.spec.ts

@@ -0,0 +1,45 @@
+import { AbstractFileSystem, path } from '@shopify/theme-check-common';
+import { MockFileSystem } from '@shopify/theme-check-common/src/test';
+import { describe, expect, it, vi } from 'vitest';
+import { DocumentManager } from '../documents';
+import { mockConnection } from '../test/MockConnection';
+import { ThemeGraphManager } from './ThemeGraphManager';
+
+describe('Module: ThemeGraphManager', () => {
+  it('rebuilds a graph that failed to build when a file changes', async () => {
+    const rootUri = path.normalize('file:/');
+    const mockFs = new MockFileSystem(
+      {
+        'assets/theme.js': '',
+        'sections/main.liquid': "{% render 'card' %}",
+        'snippets/card.liquid': '',
+      },
+      rootUri,
+    );
+    let broken = true;
+    const fs: AbstractFileSystem = {
+      stat: (uri) => mockFs.stat(uri),
+      readFile: (uri) => mockFs.readFile(uri),
+      readDirectory: (uri) =>
+        broken ? Promise.reject(new Error('EIO')) : mockFs.readDirectory(uri),
+    };
+    const connection = mockConnection(rootUri);
+    const manager = new ThemeGraphManager(
+      connection,
+      new DocumentManager(fs),
+      fs,
+      async () => rootUri,
+    );
+    const card = path.join(rootUri, 'snippets', 'card.liquid');
+
+    await expect(manager.getReferences(card)).rejects.toThrow('EIO');
+
+    broken = false;
+    vi.useFakeTimers();
+    manager.change(card);
+    await vi.runAllTimersAsync();
+    vi.useRealTimers();
+
+    expect(await manager.getReferences(card)).toHaveLength(1);
+  });
+});

packages/theme-language-server-common/src/server/ThemeGraphManager.ts

@@ -208,8 +208,10 @@ export class ThemeGraphManager {
     const rootUri = await this.findThemeRootURI(anyUri);
     if (!rootUri) return;
 
-    const graph = await this.graphs.get(rootUri);
+    const graph = this.graphs.get(rootUri);
     if (!graph) return;
+    // Let a build in progress finish first. A graph that failed to build is rebuilt too.
+    await graph.catch(() => {});
 
     this.graphs.delete(rootUri);
     await this.getThemeGraphForURI(rootUri);