Make sure non-existing icons do break the build

Summary:
Builds didn't fail when using non-existing icons, and the error message was not very clear

Also added verification that, before automatically adding an icon to the prefetcher, that icon does exists

Reviewed By: jknoxville

Differential Revision: D19264063

fbshipit-source-id: 4320d5b960e85e3f15bbca13d69f3063b983a511

scripts/build-release.js

@@ -132,11 +132,17 @@ function downloadIcons(buildFolder) {
   }, []);
 
   return Promise.all(
-    iconURLs.map(({name, size, density}) =>
-      fetch(getIconURL(name, size, density))
+    iconURLs.map(({name, size, density}) => {
+      const url = getIconURL(name, size, density);
+      return fetch(url)
         .then(res => {
           if (res.status !== 200) {
-            throw new Error(`Could not download the icon: ${name}`);
+            throw new Error(
+              // eslint-disable-next-line prettier/prettier
+              `Could not download the icon ${name} from ${url}: got status ${
+                res.status
+              }`,
+            );
           }
           return res;
         })
@@ -150,9 +156,8 @@ function downloadIcons(buildFolder) {
               res.body.on('error', reject);
               fileStream.on('finish', resolve);
             }),
-        )
-        .catch(console.error),
-    ),
+        );
+    }),
   );
 }
 

src/utils/icons.js

@@ -67,12 +67,31 @@ function buildIconURL(name, size, density) {
     if (!isProduction) {
       const existing = ICONS[name] || (ICONS[name] = []);
       if (!existing.includes(size)) {
+        // Check if that icon actually exists!
+        fetch(url)
+          .then(res => {
+            if (res.status === 200) {
+              // the icon exists
               existing.push(size);
               existing.sort();
-        fs.writeFileSync(iconsPath, JSON.stringify(ICONS, null, 2), 'utf8');
+              fs.writeFileSync(
+                iconsPath,
+                JSON.stringify(ICONS, null, 2),
+                'utf8',
+              );
               console.warn(
                 `Added uncached icon "${name}: [${size}]" to /static/icons.json. Restart Flipper to apply the change.`,
               );
+            } else {
+              throw new Error(
+                // eslint-disable-next-line prettier/prettier
+                `Trying to use icon '${name}' with size ${size} and density ${density}, however the icon doesn't seem to exists at ${url}: ${
+                  res.status
+                }`,
+              );
+            }
+          })
+          .catch(e => console.error(e));
       }
     } else {
       console.warn(

static/icons.json

@@ -15,7 +15,6 @@
     12
   ],
   "bell-null-outline": [
-    12,
     24
   ],
   "bell-null": [
@@ -73,7 +72,8 @@
     8
   ],
   "chevron-left": [
-    12
+    12,
+    16
   ],
   "chevron-right": [
     8,
@@ -205,7 +205,6 @@
     16
   ],
   "star-outline": [
-    12,
     16,
     24
   ],