fix: open redirect_to URL in browser to prevent infinite deep link loop (#22648) (#22665)

* fix: open redirect_to URL in browser to prevent infinite deep link loop

When a tracking URL's redirect_to target can't be handled in-app, open
the extracted redirect_to URL in the browser instead of the original
tracking URL. This prevents an infinite loop caused by the app's intent
filter re-intercepting its own public-api.wordpress.com/bar/ URLs.

* fix: fire server tracking pixel when redirect_to opens in browser

When a tracking URL's redirect_to target can't be handled in-app, the
app now opens the redirect destination in the browser (loop fix) but
the server never sees the original tracking URL. Fire the pixel
explicitly in this path so email link taps are still recorded.

The no-redirect fallback still opens /bar/ in the browser, which
handles tracking implicitly via the browser's HTTP request.

Co-authored-by: David Calhoun <github@davidcalhoun.me>

Author: crazytonyli

WordPress/src/main/java/org/wordpress/android/ui/deeplinks/DeepLinkingIntentReceiverViewModel.kt

@@ -131,12 +131,28 @@ class DeepLinkingIntentReceiverViewModel
 
     private fun buildNavigateAction(uri: UriWrapper, rootUri: UriWrapper = uri): NavigateAction? {
         return when {
-            deepLinkUriUtils.isTrackingUrl(uri) -> getRedirectUriAndBuildNavigateAction(uri, rootUri)
-                ?.also {
-                    // The new URL was build so we need to hit the original `mbar` tracking URL
+            deepLinkUriUtils.isTrackingUrl(uri) -> {
+                val redirectUri = deepLinkUriUtils.getRedirectUri(uri)
+                val navigateAction = redirectUri?.let { buildNavigateAction(it, rootUri) }
+                if (navigateAction != null) {
+                    // Handled in-app — fire the tracking pixel since the
+                    // server won't see the request otherwise.
                     serverTrackingHandler.request(uri)
+                    navigateAction
+                } else if (redirectUri != null) {
+                    // Can't handle in-app. Open the redirect destination
+                    // (not the tracking URL) to avoid an infinite loop with
+                    // the app's intent filter. Fire the tracking pixel
+                    // explicitly since the browser won't hit the tracking URL.
+                    serverTrackingHandler.request(uri)
+                    OpenInBrowser(redirectUri)
+                } else {
+                    // No redirect_to param — open the /bar/ tracking URL in
+                    // the browser. The browser request itself will handle
+                    // server-side tracking, so no explicit pixel needed.
+                    OpenInBrowser(rootUri.copy(REGULAR_TRACKING_PATH))
                 }
-                ?: OpenInBrowser(rootUri.copy(REGULAR_TRACKING_PATH))
+            }
             deepLinkUriUtils.isWpLoginUrl(uri) -> getRedirectUriAndBuildNavigateAction(uri, rootUri)
             else -> deepLinkHandlers.buildNavigateAction(uri)
         }

WordPress/src/test/java/org/wordpress/android/ui/deeplinks/DeepLinkingIntentReceiverViewModelTest.kt

@@ -137,26 +137,37 @@ class DeepLinkingIntentReceiverViewModelTest : BaseUnitTest() {
         val startUrl = mock<UriWrapper>()
         val wpLoginUri = initWpLoginUri(startUrl)
         val uri = initTrackingUri(wpLoginUri)
-        val barUri = buildUri("public-api.wordpress.com")
 
         whenever(deepLinkHandlers.buildNavigateAction(startUrl)).thenReturn(null)
-        whenever(uri.copy("bar")).thenReturn(barUri)
 
         viewModel.start(null, uri, DEFAULT, null)
 
-        assertUriHandled(OpenInBrowser(barUri))
+        assertUriHandled(OpenInBrowser(wpLoginUri))
+        verify(serverTrackingHandler).request(uri)
+    }
+
+    @Test
+    fun `tracking URL with unhandled direct redirect opens redirect URL in browser`() {
+        val redirectUri = buildUri("wordpress.com")
+        val uri = initTrackingUri(redirectUri)
+
+        whenever(deepLinkHandlers.buildNavigateAction(redirectUri)).thenReturn(null)
+
+        viewModel.start(null, uri, DEFAULT, null)
+
+        assertUriHandled(OpenInBrowser(redirectUri))
+        verify(serverTrackingHandler).request(uri)
     }
 
     @Test
     fun `wp-login mbar URL redirects user to browser with missing second redirect`() {
         val wpLoginUri = initWpLoginUri()
         val uri = initTrackingUri(wpLoginUri)
-        val barUri = buildUri("public-api.wordpress.com")
-        whenever(uri.copy("bar")).thenReturn(barUri)
 
         viewModel.start(null, uri, DEFAULT, null)
 
-        assertUriHandled(OpenInBrowser(barUri))
+        assertUriHandled(OpenInBrowser(wpLoginUri))
+        verify(serverTrackingHandler).request(uri)
     }
 
     @Test