Merge pull request #17022 from wordpress-mobile/issue/17020-fix-crash-on-null-designs-list

Fix crash in Site Creation flow caused by null designs list

Author: ovitrif

RELEASE-NOTES.txt

@@ -3,6 +3,7 @@
 20.6
 -----
 * [*] Login: Fix an issue preventing some users to log-in in with email addresses containing a single quote [https://github.com/wordpress-mobile/WordPress-Android/pull/15526]
+* [*] Fix a possible crash with themes preloading at the start of Site Creation [https://github.com/wordpress-mobile/WordPress-Android/pull/17022]
 
 20.5
 -----

WordPress/src/main/java/org/wordpress/android/ui/sitecreation/SiteCreationMainVM.kt

@@ -28,6 +28,8 @@ import org.wordpress.android.ui.sitecreation.misc.SiteCreationTracker
 import org.wordpress.android.ui.sitecreation.previews.SitePreviewViewModel.CreateSiteState
 import org.wordpress.android.ui.sitecreation.usecases.FetchHomePageLayoutsUseCase
 import org.wordpress.android.ui.utils.UiString.UiStringRes
+import org.wordpress.android.util.AppLog
+import org.wordpress.android.util.AppLog.T
 import org.wordpress.android.util.NetworkUtilsWrapper
 import org.wordpress.android.util.image.ImageManager
 import org.wordpress.android.util.wizard.WizardManager
@@ -124,6 +126,17 @@ class SiteCreationMainVM @Inject constructor(
             preloadingJob = viewModelScope.launch(Dispatchers.IO) {
                 if (networkUtils.isNetworkAvailable()) {
                     val response = fetchHomePageLayoutsUseCase.fetchStarterDesigns()
+
+                    // Else clause added to better understand the reason that causes this crash:
+                    // https://github.com/wordpress-mobile/WordPress-Android/issues/17020
+                    if (response.isError) {
+                        AppLog.e(T.THEMES, "Error preloading starter designs: ${response.error}")
+                        return@launch
+                    } else if (response.designs == null) {
+                        AppLog.e(T.THEMES, "Null starter designs response: $response")
+                        return@launch
+                    }
+
                     for (design in response.designs) {
                         imageManager.preload(context, MShot(design.previewMobile))
                     }