🐞 fix: Update config file handling

src/config/config.ts

@@ -111,12 +111,21 @@ function camelize(value: unknown): unknown {
   return value;
 }
 
+function objectFromNull(value: unknown): unknown {
+  return value === null ? {} : value;
+}
+
 export function expandHome(path: string): string {
   return path.startsWith('~/') ? resolve(homedir(), path.slice(2)) : path;
 }
 
 export function loadConfigFromString(source: string): AppConfig {
-  const parsed = camelize(YAML.parse(source) ?? {});
+  const parsed = camelize(YAML.parse(source) ?? {}) as Record<string, any>;
+  parsed.newsletters = objectFromNull(parsed.newsletters);
+  parsed.categories = objectFromNull(parsed.categories) as Record<string, any>;
+  if (parsed.categories && typeof parsed.categories === 'object') {
+    parsed.categories.llm = objectFromNull(parsed.categories.llm);
+  }
   return configSchema.parse(parsed);
 }
 

tests/config.test.ts

@@ -19,6 +19,28 @@ output:
     expect(config.enrichment.concurrency).toBe(3);
   });
 
+  it('treats comment-only YAML maps as empty objects', () => {
+    const config = loadConfigFromString(`
+gmail:
+  folder: Newsletters
+output:
+  name: Newsletter Link Catalog
+  excel:
+    enabled: true
+    path: ./output/catalog.xlsx
+newsletters:
+  # sender@example.com:
+categories:
+  custom:
+    - Rust
+  llm:
+    # provider: anthropic
+`);
+
+    expect(config.newsletters).toEqual({});
+    expect(config.categories.llm.provider).toBe('anthropic');
+  });
+
   it('rejects conflicting relative and absolute date filters', () => {
     expect(() => validateDateFilters({ last: '30d', from: '2026-01-01' })).toThrow(
       /cannot be combined/i