typescript-eslint · bradzacher · Apr 15, 2025 · Feb 1, 2025 · Apr 14, 2025 · Apr 14, 2025
diff --git a/packages/typescript-eslint/src/config-helper.ts b/packages/typescript-eslint/src/config-helper.ts
@@ -128,17 +128,42 @@ export function config(
       );
     }
 
-    return [
-      ...extendsArrFlattened.map(extension => {
-        const name = [config.name, extension.name].filter(Boolean).join('__');
-        return {
+    const configArray = [];
+
+    for (const extension of extendsArrFlattened) {
+      const name = [config.name, extension.name].filter(Boolean).join('__');
+      if (isPossiblyGlobalIgnores(extension)) {
+        // If it's a global ignores, then just pass it along
+        configArray.push({
+          ...extension,
+          ...(name && { name }),
+        });
+      } else {
+        configArray.push({
           ...extension,
           ...(config.files && { files: config.files }),
           ...(config.ignores && { ignores: config.ignores }),
           ...(name && { name }),
-        };
-      }),
-      config,
-    ];
+        });
+      }
+    }
+
+    // If the base config could form a global ignores object, then we mustn't include
+    // it in the output. Otherwise, we must add it in order for it to have effect.
+    if (!isPossiblyGlobalIgnores(config)) {
+      configArray.push(config);
+    }
+
+    return configArray;
   });
 }
+
+/**
+ * This utility function returns false if the config objects contains any field
+ * that would prevent it from being considered a global ignores object and true
+ * otherwise. Note in particular that the `ignores` field may not be present and
+ * the return value can still be true.
+ */
+function isPossiblyGlobalIgnores(config: object): boolean {
+  return Object.keys(config).every(key => ['name', 'ignores'].includes(key));
+}
diff --git a/packages/typescript-eslint/tests/config-helper.test.ts b/packages/typescript-eslint/tests/config-helper.test.ts
@@ -247,4 +247,73 @@ describe('config helper', () => {
       { rules: { rule: 'error' } },
     ]);
   });
+
+  it('does not create global ignores in extends', () => {
+    const configWithIgnores = plugin.config({
+      extends: [{ rules: { rule1: 'error' } }, { rules: { rule2: 'error' } }],
+      ignores: ['ignored'],
+    });
+
+    expect(configWithIgnores).toEqual([
+      { ignores: ['ignored'], rules: { rule1: 'error' } },
+      { ignores: ['ignored'], rules: { rule2: 'error' } },
+    ]);
+    expect(configWithIgnores).not.toContainEqual(
+      // Should not create global ignores
+      { ignores: ['ignored'] },
+    );
+  });
+
+  it('creates noop config in extends', () => {
+    const configWithMetadata = plugin.config({
+      extends: [{ rules: { rule1: 'error' } }, { rules: { rule2: 'error' } }],
+      files: ['file'],
+      ignores: ['ignored'],
+      name: 'my-config',
+    });
+
+    expect(configWithMetadata).toEqual([
+      {
+        files: ['file'],
+        ignores: ['ignored'],
+        name: 'my-config',
+        rules: { rule1: 'error' },
+      },
+      {
+        files: ['file'],
+        ignores: ['ignored'],
+        name: 'my-config',
+        rules: { rule2: 'error' },
+      },
+      // it would also be ok for this not to be present, but we want to align
+      // with the eslint `defineConfig()` behavior.
+      {
+        files: ['file'],
+        ignores: ['ignored'],
+        name: 'my-config',
+      },
+    ]);
+  });
+
+  it('does not create global ignores when extending empty configs', () => {
+    expect(
+      plugin.config({
+        extends: [{ rules: { rule1: 'error' } }, {}],
+        ignores: ['ignored'],
+      }),
+    ).toEqual([
+      { ignores: ['ignored'], rules: { rule1: 'error' } },
+      // Should not create global ignores
+      {},
+    ]);
+  });
+
+  it('handles name field when global-ignoring in extension', () => {
+    expect(
+      plugin.config({
+        extends: [{ ignores: ['files/**/*'], name: 'global-ignore-stuff' }],
+        ignores: ['ignored'],
+      }),
+    ).toEqual([{ ignores: ['files/**/*'], name: 'global-ignore-stuff' }]);
+  });
 });