bugfix: fixed subgraph not being preserved after navigation

e2e/subgraph-preservation.spec.ts

@@ -0,0 +1,142 @@
+import { test, expect, type Page } from '@playwright/test';
+
+async function waitForGraph(page: Page) {
+  await page.waitForSelector('svg g.node', { timeout: 15000 });
+}
+
+function nodeByLabel(page: Page, label: string) {
+  return page.locator('g.node').filter({ hasText: label });
+}
+
+async function openSubgraph(page: Page, nodeLabel: string) {
+  await nodeByLabel(page, nodeLabel).click({ button: 'right' });
+  await expect(page.locator('.ant-dropdown:visible')).toBeVisible({ timeout: 3000 });
+  await page.waitForTimeout(300);
+  await page.locator('.ant-dropdown-menu-item').filter({ hasText: 'Subgraph' }).click();
+  await waitForGraph(page);
+}
+
+const breadcrumbLinks = (page: Page) => page.locator('.ant-breadcrumb-link');
+
+test.describe('Subgraph preservation during breadcrumb navigation', () => {
+  test.beforeEach(async ({ page }) => {
+    await page.goto('/');
+    await waitForGraph(page);
+  });
+
+  test('nodes added to a subgraph are preserved after navigating to root and back', async ({ page }) => {
+    // Enter Start's subgraph and add a node
+    await openSubgraph(page, 'Start');
+    await nodeByLabel(page, 'End').click();
+    await expect(page.locator('g.node')).toHaveCount(3, { timeout: 5000 });
+
+    // Go back to main
+    await breadcrumbLinks(page).first().click();
+    await expect(breadcrumbLinks(page)).toHaveCount(1, { timeout: 3000 });
+    await waitForGraph(page);
+
+    // Re-enter the same subgraph
+    await openSubgraph(page, 'Start');
+
+    // The extra node should still be there
+    await expect(page.locator('g.node')).toHaveCount(3, { timeout: 5000 });
+  });
+
+  test('main graph is preserved when navigating into a subgraph and back', async ({ page }) => {
+    // Add a node to the main graph
+    await nodeByLabel(page, 'Start').click();
+    await expect(page.locator('g.node')).toHaveCount(3, { timeout: 5000 });
+
+    // Navigate into End's subgraph
+    await openSubgraph(page, 'End');
+
+    // Go back to main
+    await breadcrumbLinks(page).first().click();
+    await expect(breadcrumbLinks(page)).toHaveCount(1, { timeout: 3000 });
+    await waitForGraph(page);
+
+    // Main graph should still have 3 nodes
+    await expect(page.locator('g.node')).toHaveCount(3, { timeout: 5000 });
+    await expect(nodeByLabel(page, 'Start')).toBeVisible();
+    await expect(nodeByLabel(page, 'End')).toBeVisible();
+  });
+
+  test('two sibling subgraphs preserve their states independently', async ({ page }) => {
+    // Enter Start's subgraph and add 1 extra node (3 total)
+    await openSubgraph(page, 'Start');
+    await nodeByLabel(page, 'End').click();
+    await expect(page.locator('g.node')).toHaveCount(3, { timeout: 5000 });
+
+    // Back to main
+    await breadcrumbLinks(page).first().click();
+    await expect(breadcrumbLinks(page)).toHaveCount(1, { timeout: 3000 });
+    await waitForGraph(page);
+
+    // Enter End's subgraph and add 2 extra nodes (4 total)
+    await openSubgraph(page, 'End');
+    await nodeByLabel(page, 'End').click();
+    await expect(page.locator('g.node')).toHaveCount(3, { timeout: 5000 });
+    await nodeByLabel(page, 'End').click();
+    await expect(page.locator('g.node')).toHaveCount(4, { timeout: 5000 });
+
+    // Back to main
+    await breadcrumbLinks(page).first().click();
+    await expect(breadcrumbLinks(page)).toHaveCount(1, { timeout: 3000 });
+    await waitForGraph(page);
+
+    // Re-enter Start's subgraph — should still have 3 nodes
+    await openSubgraph(page, 'Start');
+    await expect(page.locator('g.node')).toHaveCount(3, { timeout: 5000 });
+
+    // Back to main
+    await breadcrumbLinks(page).first().click();
+    await waitForGraph(page);
+
+    // Re-enter End's subgraph — should still have 4 nodes
+    await openSubgraph(page, 'End');
+    await expect(page.locator('g.node')).toHaveCount(4, { timeout: 5000 });
+  });
+
+  test('intermediate level subgraph is preserved when navigating back from deeper nesting', async ({ page }) => {
+    // Enter Start's subgraph (level 1) and add a node
+    await openSubgraph(page, 'Start');
+    await nodeByLabel(page, 'End').click();
+    await expect(page.locator('g.node')).toHaveCount(3, { timeout: 5000 });
+
+    // Go one level deeper (level 2)
+    await openSubgraph(page, 'Start');
+    await expect(breadcrumbLinks(page)).toHaveCount(3, { timeout: 3000 });
+
+    // Navigate all the way back to root
+    await breadcrumbLinks(page).first().click();
+    await expect(breadcrumbLinks(page)).toHaveCount(1, { timeout: 3000 });
+    await waitForGraph(page);
+
+    // Re-enter Start's subgraph (level 1) — the 3-node state must be intact
+    await openSubgraph(page, 'Start');
+    await expect(page.locator('g.node')).toHaveCount(3, { timeout: 5000 });
+  });
+
+  test('edges added inside a subgraph are preserved after navigating away and back', async ({ page }) => {
+    // Enter Start's subgraph, create a node by clicking End, then link them
+    await openSubgraph(page, 'Start');
+    const edgeCountBefore = await page.locator('g.edge').count();
+
+    // Ctrl+click Start to select it as a parent for linking
+    await page.keyboard.down('Control');
+    await nodeByLabel(page, 'Start').click();
+    await page.keyboard.up('Control');
+    // Click End without Ctrl to link selected Start → End
+    await nodeByLabel(page, 'End').click();
+    await expect(page.locator('g.edge')).toHaveCount(edgeCountBefore + 1, { timeout: 5000 });
+
+    // Navigate back to main
+    await breadcrumbLinks(page).first().click();
+    await expect(breadcrumbLinks(page)).toHaveCount(1, { timeout: 3000 });
+    await waitForGraph(page);
+
+    // Re-enter the subgraph — extra edge must still be there
+    await openSubgraph(page, 'Start');
+    await expect(page.locator('g.edge')).toHaveCount(edgeCountBefore + 1, { timeout: 5000 });
+  });
+});

src/components/Graph.tsx

@@ -68,8 +68,11 @@ export default function Graph({ setGraphPath }: { setGraphPath: React.Dispatch<R
   const [contextMenuOpened, openContextMenu] = useState(false);
   const [renameModalOpened, openRenameModal] = useState(false);
   const [graphId, selectGraphId] = useState('main');
+  const graphIdRef = useRef(graphId);
   const [graphsPath, setGraphsPath] = useState([createPathSegment('main', 'Main')])
   const [nodeContext, openNodeContext] = useState<null | NodeContext>(null);  
+  graphIdRef.current = graphId;
+
   const graphContextValue = {
     graphId: graphId,
     selectGraphId: selectGraphId,
@@ -92,6 +95,15 @@ export default function Graph({ setGraphPath }: { setGraphPath: React.Dispatch<R
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [graph]);
 
+  // Persist graph edits to the store so they survive breadcrumb navigation.
+  // We intentionally read graphId via ref (not as a dep) so this effect only
+  // fires on graph content changes, never on navigation (graphId changes).
+  useEffect(() => {
+    const state = useGraphsStore.getState() as { graphsById: Map<string, GraphModel> };
+    state.graphsById.set(graphIdRef.current, graph);
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [graph]);
+
   useEffect(() => {
     if (nodeContext) {
       openContextMenu(true);