fix: keep empty {:catch} in {#await} blocks

.changeset/keep-empty-await-catch.md

@@ -0,0 +1,5 @@
+---
+'prettier-plugin-svelte': patch
+---
+
+fix: keep empty `{:catch}` in `{#await}` blocks (removing it turns a handled rejection into an unhandled one)

src/print/index.ts

@@ -529,10 +529,10 @@ export function print(path: AstPath, options: ParserOptions, print: PrintFn): Do
         case 'AwaitBlock': {
             const pending_children = node.pending?.nodes ?? [];
             const then_children = node.then?.nodes ?? [];
-            const catch_children = node.catch?.nodes ?? [];
             const hasPendingBlock = pending_children.some((n) => !isEmptyTextNode(n));
             const hasThenBlock = then_children.some((n) => !isEmptyTextNode(n));
-            const hasCatchBlock = catch_children.some((n) => !isEmptyTextNode(n));
+            // Keep an empty `{:catch}`: without one, Svelte rethrows the rejection
+            const hasCatchBlock = !!node.catch;
 
             let block = [];
 

test/printer/samples/await-block-empty-catch.html

@@ -0,0 +1,5 @@
+{#await thePromise then theValue}
+    <p>the value is {theValue}</p>
+{:catch}{/await}
+
+{#await thePromise catch}{/await}