fix(schema-compiler): Yaml - crash on fully commented file (#6413)

Author: ovr

packages/cubejs-schema-compiler/src/compiler/YamlCompiler.ts

@@ -31,6 +31,10 @@ export class YamlCompiler {
     }
 
     const yamlObj = YAML.load(file.content);
+    if (!yamlObj) {
+      return;
+    }
+
     for (const key of Object.keys(yamlObj)) {
       if (key === 'cubes') {
         (yamlObj.cubes || []).forEach(({ name, ...cube }) => {

packages/cubejs-schema-compiler/test/unit/yaml-schema.test.ts

@@ -1,5 +1,4 @@
-import { prepareCompiler, prepareYamlCompiler } from './PrepareCompiler';
-import { createCubeSchema } from './utils';
+import { prepareYamlCompiler } from './PrepareCompiler';
 
 describe('Yaml Schema Testing', () => {
   it('members must be defined as arrays', async () => {
@@ -23,4 +22,20 @@ describe('Yaml Schema Testing', () => {
       expect(e.message).toContain('dimensions must be defined as array');
     }
   });
+
+  it('commented file crash', async () => {
+    const { compiler } = prepareYamlCompiler(
+      `
+      #cubes:
+      #- name: Products
+      #  sql: "select * from tbl"
+      #  dimensions:
+      #    name: Title
+      #    sql: name
+      #    type: string
+      `
+    );
+
+    await compiler.compile();
+  });
 });