feat: allow disabling remote extend with giget: false

README.md

@@ -188,6 +188,8 @@ The final config is merged result of extended options and user options with [unj
 Each item in extends is a string that can be either an absolute or relative path to the current config file pointing to a config file for extending or the directory containing the config file.
 If it starts with either `github:`, `gitlab:`, `bitbucket:`, or `https:`, c12 automatically clones it.
 
+You can set the `extendOptions` option when loading the config (with `loadConfig`) to customize the extending behavior like ignoring remote sources.
+
 For custom merging strategies, you can directly access each layer with `layers` property.
 
 **Example:**

src/loader.ts

@@ -250,6 +250,25 @@ async function extendConfig<
       );
       continue;
     }
+
+    // Skipping remote sources if set up
+    const skipRemote = options?.extendOptions?.skipRemote;
+    const isGiGetSource = GIGET_PREFIXES.some((prefix) =>
+      extendSource.startsWith(prefix),
+    );
+    const isNPMSource = NPM_PACKAGE_RE.test(extendSource);
+    if (skipRemote && (isNPMSource || isGiGetSource)) {
+      if (skipRemote === true) continue;
+
+      const hasAuth = Boolean((sourceOptions as SourceOptions)?.auth);
+      const skippingGitgetSource =
+        isGiGetSource && !(hasAuth ? skipRemote.allowAuth : false);
+      if (skippingGitgetSource) continue;
+
+      const skippingNPMSource = isNPMSource && !skipRemote.allowNPM;
+      if (skippingNPMSource) continue;
+    }
+
     const _config = await resolveConfig(extendSource, options, sourceOptions);
     if (!_config.config) {
       // TODO: Use error in next major versions

src/types.ts

@@ -140,6 +140,27 @@ export interface LoadConfigOptions<
     | {
         extendKey?: string | string[];
       };
+  /**
+   * Options for extending configs
+   */
+  extendOptions?: {
+    /**
+     * Skip and ignore remote configs when extending. This blocks downloading configs
+     * from github or npm, only local configs will be used.
+     */
+    skipRemote?:
+      | boolean
+      | {
+          /**
+           * Allow extending configs with auth tokens.
+           */
+          allowAuth?: boolean;
+          /**
+           * Allow extending configs from npm.
+           */
+          allowNPM?: boolean;
+        };
+  };
 }
 
 export type DefineConfig<

test/loader.test.ts

@@ -260,6 +260,57 @@ describe("loader", () => {
     `);
   });
 
+  it("skip remote configs", async () => {
+    type Config = {
+      extends?: string[];
+      defaultValue?: boolean;
+      npmValue?: boolean;
+    };
+    const opts = {
+      name: "test",
+      cwd: r("./fixture/new_dir"),
+      overrides: {
+        extends: ["virtual", "github:unjs/c12/test/fixture"],
+      },
+      resolve: (id: string) => {
+        if (id === "virtual") {
+          return { config: { npmValue: true } };
+        }
+      },
+      defaultConfig: {
+        defaultValue: true,
+      },
+    };
+    const { config: remoteConfig } = await loadConfig<Config>({
+      ...opts,
+      extendOptions: {
+        skipRemote: true,
+      },
+    });
+
+    const { config: npmConfig } = await loadConfig<Config>({
+      ...opts,
+      extendOptions: {
+        skipRemote: {
+          allowAuth: false,
+          allowNPM: true,
+        },
+      },
+    });
+
+    expect(transformPaths(remoteConfig!)).toMatchInlineSnapshot(`
+      {
+        "defaultValue": true,
+      }
+    `);
+    expect(transformPaths(npmConfig!)).toMatchInlineSnapshot(`
+      {
+        "defaultValue": true,
+        "npmValue": true,
+      }
+    `);
+  });
+
   it("omit$Keys", async () => {
     const { config, layers } = await loadConfig({
       name: "test",