guard against empty cif files

CHANGELOG.md

@@ -8,6 +8,7 @@ Note that since we don't clearly distinguish between a public and private interf
 
 - Fix return type of `State.tryGetCellData`
 - Don't change camera.target unless flyMode or pointerLock are enabled
+- Handle empty CIF files
 
 ## [v3.42.0] - 2023-11-05
 

src/mol-plugin-state/transforms/data.ts

@@ -284,6 +284,7 @@ const ParseCif = PluginStateTransform.BuiltIn({
         return Task.create('Parse CIF', async ctx => {
             const parsed = await (typeof a.data === 'string' ? CIF.parse(a.data) : CIF.parseBinary(a.data)).runInContext(ctx);
             if (parsed.isError) throw new Error(parsed.message);
+            if (parsed.result.blocks.length === 0) return StateObject.Null;
             return new SO.Format.Cif(parsed.result);
         });
     }