fix(snapshotter): support constructed CSSStyleSheet

Fixes #7085

src/server/snapshot/snapshotRenderer.ts

@@ -124,7 +124,7 @@ function snapshotNodes(snapshot: FrameSnapshot): NodeSnapshot[] {
 }
 
 function snapshotScript() {
-  function applyPlaywrightAttributes(shadowAttribute: string, scrollTopAttribute: string, scrollLeftAttribute: string) {
+  function applyPlaywrightAttributes(shadowAttribute: string, scrollTopAttribute: string, scrollLeftAttribute: string, styleSheetAttribute: string) {
     const scrollTops: Element[] = [];
     const scrollLefts: Element[] = [];
 
@@ -152,6 +152,17 @@ function snapshotScript() {
         template.remove();
         visit(shadowRoot);
       }
+
+      if ('adoptedStyleSheets' in (root as any)) {
+        const adoptedSheets: CSSStyleSheet[] = [...(root as any).adoptedStyleSheets];
+        for (const element of root.querySelectorAll(`template[${styleSheetAttribute}]`)) {
+          const template = element as HTMLTemplateElement;
+          const sheet = new CSSStyleSheet();
+          (sheet as any).replaceSync(template.getAttribute(styleSheetAttribute));
+          adoptedSheets.push(sheet);
+        }
+        (root as any).adoptedStyleSheets = adoptedSheets;
+    }
     };
     visit(document);
 
@@ -172,5 +183,6 @@ function snapshotScript() {
   const kShadowAttribute = '__playwright_shadow_root_';
   const kScrollTopAttribute = '__playwright_scroll_top_';
   const kScrollLeftAttribute = '__playwright_scroll_left_';
-  return `\n(${applyPlaywrightAttributes.toString()})('${kShadowAttribute}', '${kScrollTopAttribute}', '${kScrollLeftAttribute}')`;
+  const kStyleSheetAttribute = '__playwright_style_sheet_';
+  return `\n(${applyPlaywrightAttributes.toString()})('${kShadowAttribute}', '${kScrollTopAttribute}', '${kScrollLeftAttribute}', '${kStyleSheetAttribute}')`;
 }

src/server/snapshot/snapshotterInjected.ts

@@ -39,6 +39,7 @@ export function frameSnapshotStreamer(snapshotStreamer: string) {
   const kShadowAttribute = '__playwright_shadow_root_';
   const kScrollTopAttribute = '__playwright_scroll_top_';
   const kScrollLeftAttribute = '__playwright_scroll_left_';
+  const kStyleSheetAttribute = '__playwright_style_sheet_';
 
   // Symbols for our own info on Nodes/StyleSheets.
   const kSnapshotFrameId = Symbol('__playwright_snapshot_frameid_');
@@ -296,6 +297,15 @@ export function frameSnapshotStreamer(snapshotStreamer: string) {
           }
         };
 
+        const visitChildStyleSheet = (child: CSSStyleSheet) => {
+          const snapshot = visitStyleSheet(child);
+          if (snapshot) {
+            result.push(snapshot.n);
+            expectValue(child);
+            equals = equals && snapshot.equals;
+          }
+        };
+
         if (nodeType === Node.DOCUMENT_FRAGMENT_NODE)
           attrs[kShadowAttribute] = 'open';
 
@@ -345,6 +355,15 @@ export function frameSnapshotStreamer(snapshotStreamer: string) {
           }
           for (let child = node.firstChild; child; child = child.nextSibling)
             visitChild(child);
+          let documentOrShadowRoot = null;
+          if (node.ownerDocument!.documentElement === node)
+            documentOrShadowRoot = node.ownerDocument;
+          else if (node.nodeType === Node.DOCUMENT_FRAGMENT_NODE)
+            documentOrShadowRoot = node;
+          if (documentOrShadowRoot) {
+            for (const sheet of (documentOrShadowRoot as any).adoptedStyleSheets || [])
+              visitChildStyleSheet(sheet);
+          }
         }
 
         // Process iframe src attribute before bailing out since it depends on a symbol, not the DOM.
@@ -397,6 +416,21 @@ export function frameSnapshotStreamer(snapshotStreamer: string) {
         return checkAndReturn(result);
       };
 
+      const visitStyleSheet = (sheet: CSSStyleSheet) => {
+        const data = ensureCachedData(sheet);
+        const oldCSSText = data.cssText;
+        const cssText = this._updateStyleElementStyleSheetTextIfNeeded(sheet) || '';
+        if (cssText === oldCSSText)
+          return { equals: true, n: [[ snapshotNumber - data.ref![0], data.ref![1] ]] };
+        data.ref = [snapshotNumber, nodeCounter++];
+        return {
+          equals: false,
+          n: ['template', {
+            [kStyleSheetAttribute]: cssText,
+          }]
+        };
+      };
+
       let html: NodeSnapshot;
       if (document.documentElement) {
         const { n } = visitNode(document.documentElement)!;

tests/snapshotter.spec.ts

@@ -75,6 +75,14 @@ it.describe('snapshots', () => {
     expect(distillSnapshot(snapshot2)).toBe('<style>button { color: blue; }</style><BUTTON>Hello</BUTTON>');
   });
 
+  it('should have a custom doctype', async ({page, server, toImpl, snapshotter}) => {
+    await page.goto(server.EMPTY_PAGE);
+    await page.setContent('<!DOCTYPE foo><body>hi</body>');
+
+    const snapshot = await snapshotter.captureSnapshot(toImpl(page), 'snapshot');
+    expect(distillSnapshot(snapshot)).toBe('<!DOCTYPE foo>hi');
+  });
+
   it('should respect subresource CSSOM change', async ({ page, server, toImpl, snapshotter }) => {
     await page.goto(server.EMPTY_PAGE);
     await page.route('**/style.css', route => {
@@ -166,6 +174,49 @@ it.describe('snapshots', () => {
       expect(distillSnapshot(snapshot)).toBe('<BUTTON data="two">Hello</BUTTON>');
     }
   });
+
+  it('should contain adopted style sheets', async ({ page, toImpl, contextFactory, snapshotPort, snapshotter, browserName }) => {
+    it.skip(browserName !== 'chromium', 'Constructed stylesheets are only in Chromium.');
+    await page.setContent('<button>Hello</button>');
+    await page.evaluate(() => {
+      const sheet = new CSSStyleSheet();
+      sheet.addRule('button', 'color: red');
+      (document as any).adoptedStyleSheets = [sheet];
+
+      const div = document.createElement('div');
+      const root = div.attachShadow({
+        mode: 'open'
+      });
+      root.append('foo');
+      const sheet2 = new CSSStyleSheet();
+      sheet2.addRule(':host', 'color: blue');
+      (root as any).adoptedStyleSheets = [sheet2];
+      document.body.appendChild(div);
+    });
+    const snapshot1 = await snapshotter.captureSnapshot(toImpl(page), 'snapshot1');
+
+    const previewContext = await contextFactory();
+    const previewPage = await previewContext.newPage();
+    previewPage.on('console', console.log);
+    await previewPage.goto(`http://localhost:${snapshotPort}/snapshot/`);
+    await previewPage.evaluate(snapshotId => {
+      (window as any).showSnapshot(snapshotId);
+    }, `${snapshot1.snapshot().pageId}?name=snapshot1`);
+    // wait for the render frame to load
+    while (previewPage.frames().length < 2)
+      await new Promise(f => previewPage.once('frameattached', f));
+    // wait for it to render
+    await previewPage.frames()[1].waitForSelector('button');
+    const buttonColor = await previewPage.frames()[1].$eval('button', button => {
+      return window.getComputedStyle(button).color;
+    });
+    expect(buttonColor).toBe('rgb(255, 0, 0)');
+    const divColor = await previewPage.frames()[1].$eval('div', div => {
+      return window.getComputedStyle(div).color;
+    });
+    expect(divColor).toBe('rgb(0, 0, 255)');
+    await previewContext.close();
+  });
 });
 
 function distillSnapshot(snapshot) {