Handle the error if the icon is not loadable (#6344). (#6944)

flow-server/src/main/java/com/vaadin/flow/server/PwaRegistry.java

@@ -32,11 +32,13 @@
 import java.util.List;
 import java.util.stream.Collectors;
 
+import com.vaadin.flow.server.frontend.FrontendUtils;
 import com.vaadin.flow.server.startup.ApplicationRouteRegistry;
 
 import elemental.json.Json;
 import elemental.json.JsonArray;
 import elemental.json.JsonObject;
+import org.slf4j.LoggerFactory;
 
 /**
  * Registry for PWA data.
@@ -90,11 +92,15 @@ private PwaRegistry(PWA pwa, ServletContext servletContext)
             // fall back to local image if unavailable
             BufferedImage baseImage = getBaseImage(logo);
 
-            // Pick top-left pixel as fill color if needed for image resizing
-            int bgColor = baseImage.getRGB(0, 0);
+            if (baseImage == null) {
+                LoggerFactory.getLogger(PwaRegistry.class).error("Image is not found or can't be loaded: " + logo);
+            } else {
+                // Pick top-left pixel as fill color if needed for image resizing
+                int bgColor = baseImage.getRGB(0, 0);
 
-            // initialize icons
-            icons = initializeIcons(baseImage, bgColor);
+                // initialize icons
+                icons = initializeIcons(baseImage, bgColor);
+            }
 
             // Load offline page as string, from servlet context if
             // available, fall back to default page

flow-tests/test-misc/src/main/java/com/vaadin/flow/misc/ui/MiscelaneousView.java

@@ -20,6 +20,7 @@
 import com.vaadin.flow.component.html.Div;
 import com.vaadin.flow.misc.ui.MiscelaneousView.MyTheme;
 import com.vaadin.flow.router.Route;
+import com.vaadin.flow.server.PWA;
 import com.vaadin.flow.theme.AbstractTheme;
 import com.vaadin.flow.theme.Theme;
 
@@ -31,8 +32,11 @@
 
 //`src/` in component above should be replaced by `theme/my-theme`
 @Theme(MyTheme.class)
+@PWA(name = "Project Base for Vaadin", shortName = "Project Base")
 public class MiscelaneousView extends Div {
-
+
+    public static final String TEST_VIEW_ID = "MiscellaneousView";
+
     public static class MyTheme implements AbstractTheme {
         @Override
         public String getBaseUrl() {
@@ -46,5 +50,6 @@ public String getThemeUrl() {
     }
 
     public MiscelaneousView() {
+        setId(TEST_VIEW_ID);
     }
 }

flow-tests/test-misc/src/test/java/com/vaadin/flow/misc/ui/MiscelaneousIT.java

@@ -46,4 +46,19 @@ public void should_loadThemedComponent_fromLocal() {
         WebElement body = findElement(By.tagName("body"));
         Assert.assertEquals("2px", body.getCssValue("padding"));
     }
+
+    /**
+     * Checks that a missing or incorrect icon is handled properly with an
+     * error log and does not halt the whole application startup.
+     */
+    @Test
+    public void handlesIncorrectIconProperly() {
+        open();
+
+        checkLogsForErrors();
+
+        Assert.assertTrue(
+                "Missing/invalid icons at startup should be handled with error log.",
+                isElementPresent(By.id(MiscelaneousView.TEST_VIEW_ID)));
+    }
 }