Turn Browser panics into errors

browser/browser_mapping.go

@@ -56,14 +56,14 @@ func mapBrowser(vu moduleVU) mapping { //nolint:funlen,cyclop
 			if err != nil {
 				return "", err
 			}
-			return b.UserAgent(), nil
+			return b.UserAgent() //nolint:wrapcheck
 		},
 		"version": func() (string, error) {
 			b, err := vu.browser()
 			if err != nil {
 				return "", err
 			}
-			return b.Version(), nil
+			return b.Version() //nolint:wrapcheck
 		},
 		"newPage": func(opts goja.Value) (mapping, error) {
 			b, err := vu.browser()

browser/mapping_test.go

@@ -255,8 +255,8 @@ type browserAPI interface {
 	NewContext(opts goja.Value) (*common.BrowserContext, error)
 	NewPage(opts goja.Value) (*common.Page, error)
 	On(string) (bool, error)
-	UserAgent() string
-	Version() string
+	UserAgent() (string, error)
+	Version() (string, error)
 }
 
 // browserContextAPI is the public interface of a CDP browser context.

common/browser.go

@@ -172,7 +172,7 @@ func (b *Browser) getPages() []*Page {
 	return pages
 }
 
-func (b *Browser) initEvents() error {
+func (b *Browser) initEvents() error { //nolint:cyclop
 	var cancelCtx context.Context
 	cancelCtx, b.evCancelFn = context.WithCancel(b.ctx)
 	chHandler := make(chan Event)
@@ -198,7 +198,9 @@ func (b *Browser) initEvents() error {
 			case event := <-chHandler:
 				if ev, ok := event.data.(*target.EventAttachedToTarget); ok {
 					b.logger.Debugf("Browser:initEvents:onAttachedToTarget", "sid:%v tid:%v", ev.SessionID, ev.TargetInfo.TargetID)
-					b.onAttachedToTarget(ev)
+					if err := b.onAttachedToTarget(ev); err != nil {
+						k6ext.Panic(b.ctx, "browser is attaching to target: %w", err)
+					}
 				} else if ev, ok := event.data.(*target.EventDetachedFromTarget); ok {
 					b.logger.Debugf("Browser:initEvents:onDetachedFromTarget", "sid:%v", ev.SessionID)
 					b.onDetachedFromTarget(ev)
@@ -247,7 +249,7 @@ func (b *Browser) connectionOnAttachedToTarget(eva *target.EventAttachedToTarget
 }
 
 // onAttachedToTarget is called when a new page is attached to the browser.
-func (b *Browser) onAttachedToTarget(ev *target.EventAttachedToTarget) {
+func (b *Browser) onAttachedToTarget(ev *target.EventAttachedToTarget) error {
 	b.logger.Debugf("Browser:onAttachedToTarget", "sid:%v tid:%v bctxid:%v",
 		ev.SessionID, ev.TargetInfo.TargetID, ev.TargetInfo.BrowserContextID)
 
@@ -257,14 +259,14 @@ func (b *Browser) onAttachedToTarget(ev *target.EventAttachedToTarget) {
 	)
 
 	if !b.isAttachedPageValid(ev, browserCtx) {
-		return // Ignore this page.
+		return nil // Ignore this page.
 	}
 	session := b.conn.getSession(ev.SessionID)
 	if session == nil {
 		b.logger.Debugf("Browser:onAttachedToTarget",
 			"session closed before attachToTarget is handled. sid:%v tid:%v",
 			ev.SessionID, targetPage.TargetID)
-		return // ignore
+		return nil // ignore
 	}
 
 	var (
@@ -281,17 +283,21 @@ func (b *Browser) onAttachedToTarget(ev *target.EventAttachedToTarget) {
 	}
 	p, err := NewPage(b.ctx, session, browserCtx, targetPage.TargetID, opener, isPage, b.logger)
 	if err != nil && b.isPageAttachmentErrorIgnorable(ev, session, err) {
-		return // Ignore this page.
+		return nil // Ignore this page.
 	}
 	if err != nil {
-		k6ext.Panic(b.ctx, "creating a new %s: %w", targetPage.Type, err)
+		return fmt.Errorf("creating a new %s: %w", targetPage.Type, err)
 	}
+
 	b.attachNewPage(p, ev) // Register the page as an active page.
+
 	// Emit the page event only for pages, not for background pages.
 	// Background pages are created by extensions.
 	if isPage {
 		browserCtx.emit(EventBrowserContextPage, p)
 	}
+
+	return nil
 }
 
 // attachNewPage registers the page as an active page and attaches the sessionID with the targetID.
@@ -622,27 +628,27 @@ func (b *Browser) On(event string) (bool, error) {
 }
 
 // UserAgent returns the controlled browser's user agent string.
-func (b *Browser) UserAgent() string {
+func (b *Browser) UserAgent() (string, error) {
 	action := cdpbrowser.GetVersion()
-	_, _, _, ua, _, err := action.Do(cdp.WithExecutor(b.ctx, b.conn))
+	_, _, _, ua, _, err := action.Do(cdp.WithExecutor(b.ctx, b.conn)) //nolint:dogsled
 	if err != nil {
-		k6ext.Panic(b.ctx, "getting browser user agent: %w", err)
+		return "", fmt.Errorf("getting browser user agent: %w", err)
 	}
-	return ua
+	return ua, nil
 }
 
 // Version returns the controlled browser's version.
-func (b *Browser) Version() string {
+func (b *Browser) Version() (string, error) {
 	action := cdpbrowser.GetVersion()
-	_, product, _, _, _, err := action.Do(cdp.WithExecutor(b.ctx, b.conn))
+	_, product, _, _, _, err := action.Do(cdp.WithExecutor(b.ctx, b.conn)) //nolint:dogsled
 	if err != nil {
-		k6ext.Panic(b.ctx, "getting browser version: %w", err)
+		return "", fmt.Errorf("getting browser version: %w", err)
 	}
 	i := strings.Index(product, "/")
 	if i == -1 {
-		return product
+		return product, nil
 	}
-	return product[i+1:]
+	return product[i+1:], nil
 }
 
 // WsURL returns the Websocket URL that the browser is listening on for CDP clients.

tests/browser_test.go

@@ -195,8 +195,10 @@ func TestBrowserVersion(t *testing.T) {
 	t.Parallel()
 
 	const re = `^\d+\.\d+\.\d+\.\d+$`
-	r, _ := regexp.Compile(re)
-	ver := newTestBrowser(t).Version()
+	r, err := regexp.Compile(re) //nolint:gocritic
+	require.NoError(t, err)
+	ver, err := newTestBrowser(t).Version()
+	require.NoError(t, err)
 	assert.Regexp(t, r, ver, "expected browser version to match regex %q, but found %q", re, ver)
 }
 
@@ -210,7 +212,8 @@ func TestBrowserUserAgent(t *testing.T) {
 
 	// testBrowserVersion() tests the version already
 	// just look for "Headless" in UserAgent
-	ua := b.UserAgent()
+	ua, err := b.UserAgent()
+	require.NoError(t, err)
 	if prefix := "Mozilla/5.0"; !strings.HasPrefix(ua, prefix) {
 		t.Errorf("UserAgent should start with %q, but got: %q", prefix, ua)
 	}