feat!: Add --manifest option for custom manifest to dev server

packages/examples/packages/bip32/snap.manifest.dev.json

@@ -0,0 +1,51 @@
+{
+  "version": "2.3.0",
+  "description": "MetaMask example snap demonstrating the use of `snap_getBip32Entropy`.",
+  "proposedName": "BIP-32 Example Snap",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/MetaMask/snaps.git"
+  },
+  "source": {
+    "shasum": "yW/4a7WQ2dCmZHAaX6P2tihFF7azVPkpQ0iJlb/v61A=",
+    "location": {
+      "npm": {
+        "filePath": "dist/bundle.js",
+        "packageName": "@metamask/bip32-example-snap",
+        "registry": "https://registry.npmjs.org"
+      }
+    }
+  },
+  "initialConnections": {
+    "http://localhost:9000": {}
+  },
+  "initialPermissions": {
+    "endowment:rpc": {
+      "dapps": true,
+      "snaps": true
+    },
+    "snap_dialog": {},
+    "snap_getBip32Entropy": [
+      {
+        "path": ["m", "44'", "0'"],
+        "curve": "secp256k1"
+      },
+      {
+        "path": ["m", "44'", "0'"],
+        "curve": "ed25519"
+      },
+      {
+        "path": ["m", "44'", "0'"],
+        "curve": "ed25519Bip32"
+      }
+    ],
+    "snap_getBip32PublicKey": [
+      {
+        "path": ["m", "44'", "0'"],
+        "curve": "secp256k1"
+      }
+    ]
+  },
+  "platformVersion": "10.3.0",
+  "manifestVersion": "0.1"
+}

packages/snaps-cli/src/builders.ts

@@ -36,6 +36,13 @@ const builders = {
     normalize: true,
   },
 
+  manifest: {
+    alias: 'm',
+    describe: 'Path to snap.manifest.json file',
+    type: 'string',
+    normalize: true,
+  },
+
   port: {
     alias: 'p',
     describe: 'Local server port for testing',

packages/snaps-cli/src/commands/manifest/implementation.test.ts

@@ -8,6 +8,7 @@ import {
 import type { SemVerVersion } from '@metamask/utils';
 import normalFs from 'fs';
 import ora from 'ora';
+import { join } from 'path';
 
 import { manifest } from './implementation';
 import type * as webpack from '../../webpack';
@@ -74,7 +75,7 @@ describe('manifest', () => {
 
     const spinner = ora();
     const result = await manifest(
-      '/snap/snap.manifest.json',
+      join('/snap', 'snap.manifest.json'),
       false,
       undefined,
       spinner,
@@ -97,7 +98,7 @@ describe('manifest', () => {
 
     const spinner = ora();
     const result = await manifest(
-      '/snap/snap.manifest.json',
+      join('/snap', 'snap.manifest.json'),
       false,
       undefined,
       spinner,
@@ -132,7 +133,7 @@ describe('manifest', () => {
 
     const spinner = ora();
     const result = await manifest(
-      '/snap/snap.manifest.json',
+      join('/snap', 'snap.manifest.json'),
       true,
       undefined,
       spinner,
@@ -155,7 +156,7 @@ describe('manifest', () => {
     const log = jest.spyOn(console, 'log').mockImplementation();
 
     await fs.writeFile(
-      '/snap/snap.manifest.json',
+      join('/snap', 'snap.manifest.json'),
       JSON.stringify(
         getSnapManifest({
           shasum: 'G/W5b2JZVv+epgNX9pkN63X6Lye9EJVJ4NLSgAw/afd=',

packages/snaps-cli/src/commands/manifest/implementation.ts

@@ -26,7 +26,12 @@ export async function manifest(
   exports?: string[],
   spinner?: Ora,
 ): Promise<boolean> {
-  const { reports, updated } = await checkManifest(dirname(path), {
+  /* eslint-disable no-console */
+  console.log('Checking manifest at path:', path);
+  console.log('Dirname:', dirname(path));
+  /* eslint-enable no-console */
+
+  const { reports, updated } = await checkManifest(path, {
     exports,
     handlerEndowments,
     updateAndWriteManifest: write,

packages/snaps-cli/src/commands/watch/index.test.ts

@@ -5,9 +5,10 @@ import type { YargsArgs } from '../../types/yargs';
 
 jest.mock('./watch');
 
-const getMockArgv = () => {
+const getMockArgv = (manifest?: string | undefined) => {
   return {
     context: { config: getMockConfig() },
+    manifest,
   } as unknown as YargsArgs;
 };
 
@@ -16,4 +17,18 @@ describe('watch command', () => {
     await command.handler(getMockArgv());
     expect(watchHandler).toHaveBeenCalled();
   });
+
+  it('calls the `watchHandler` function with a custom manifest path', async () => {
+    await command.handler(getMockArgv('/custom.json'));
+    expect(watchHandler).toHaveBeenCalledWith(
+      expect.objectContaining({
+        manifest: expect.objectContaining({
+          path: expect.stringContaining('custom.json'),
+        }),
+      }),
+      {
+        port: undefined,
+      },
+    );
+  });
 });

packages/snaps-cli/src/commands/watch/index.ts

@@ -1,3 +1,4 @@
+import { resolve } from 'path';
 import type yargs from 'yargs';
 
 import { watchHandler } from './watch';
@@ -8,12 +9,23 @@ const command = {
   command: ['watch', 'w'],
   desc: 'Build Snap on change',
   builder: (yarg: yargs.Argv) => {
-    yarg.option('port', builders.port);
+    yarg.option('port', builders.port).option('manifest', builders.manifest);
   },
-  handler: async (argv: YargsArgs) =>
-    watchHandler(argv.context.config, {
+  handler: async (argv: YargsArgs) => {
+    const configWithManifest = argv.manifest
+      ? {
+          ...argv.context.config,
+          manifest: {
+            ...argv.context.config.manifest,
+            path: resolve(process.cwd(), argv.manifest),
+          },
+        }
+      : argv.context.config;
+
+    return await watchHandler(configWithManifest, {
       port: argv.port,
-    }),
+    });
+  },
 };
 
 export * from './implementation';

packages/snaps-cli/src/types/yargs.d.ts

@@ -33,6 +33,7 @@ type YargsArgs = {
   dist: string;
   src: string;
   eval: boolean;
+  manifest?: string;
   outfileName: string;
   serve: boolean;
   directory?: string;

packages/snaps-cli/src/webpack/server.test.ts

@@ -139,7 +139,8 @@ describe('getAllowedPaths', () => {
 
 describe('getServer', () => {
   beforeEach(async () => {
-    await fs.mkdir('/foo', { recursive: true });
+    await fs.mkdir('/foo/dist', { recursive: true });
+    await fs.writeFile('/foo/dist/bundle.js', 'console.log("Hello, world!");');
     await fs.writeFile(
       '/foo/snap.manifest.json',
       JSON.stringify(getSnapManifest()),
@@ -207,17 +208,53 @@ describe('getServer', () => {
         root: '/foo',
         port: 0,
       },
+      output: {
+        path: '/foo/dist',
+      },
+      manifest: {
+        path: '/foo/snap.manifest.json',
+      },
     });
 
     const server = getServer(config);
     const { port, close } = await server.listen();
 
     const response = await fetch(
-      `http://localhost:${port}/snap.manifest.json?_=1731493314736`,
+      `http://localhost:${port}/dist/bundle.js?_=1731493314736`,
+    );
+
+    expect(response.status).toBe(200);
+    expect(await response.text()).toBe('console.log("Hello, world!");');
+
+    await close();
+  });
+
+  it('responds with a custom manifest file', async () => {
+    const config = getMockConfig({
+      input: 'src/index.js',
+      server: {
+        root: '/foo',
+        port: 0,
+      },
+      manifest: {
+        path: '/foo/snap.manifest.dev.json',
+      },
+    });
+
+    const server = getServer(config);
+    const { port, close } = await server.listen();
+
+    // Create a custom manifest file in the /foo/dist directory
+    const customManifest = getSnapManifest({ proposedName: 'Dev Snap' });
+    await fs.writeFile(
+      '/foo/snap.manifest.dev.json',
+      JSON.stringify(customManifest),
     );
 
+    const response = await fetch(`http://localhost:${port}/snap.manifest.json`);
+
     expect(response.status).toBe(200);
-    expect(await response.text()).toBe(JSON.stringify(getSnapManifest()));
+    expect(await response.text()).toBe(JSON.stringify(customManifest));
 
     await close();
   });
@@ -229,6 +266,9 @@ describe('getServer', () => {
         root: '/foo',
         port: 0,
       },
+      manifest: {
+        path: '/foo/snap.manifest.json',
+      },
     });
 
     const server = getServer(config);

packages/snaps-cli/src/webpack/server.ts

@@ -4,7 +4,7 @@ import type { Express, Request } from 'express';
 import express, { static as expressStatic } from 'express';
 import type { Server } from 'http';
 import type { AddressInfo } from 'net';
-import { join, relative, resolve as resolvePath, sep, posix } from 'path';
+import { relative, resolve as resolvePath, sep, posix } from 'path';
 
 import type { ProcessedConfig } from '../config';
 
@@ -91,8 +91,10 @@ export function getAllowedPaths(
  * `false` if it is not.
  */
 async function isAllowedPath(request: Request, config: ProcessedConfig) {
-  const manifestPath = join(config.server.root, NpmSnapFileNames.Manifest);
-  const { result } = await readJsonFile<SnapManifest>(manifestPath);
+  const { result } = await readJsonFile<SnapManifest>(
+    resolvePath(config.server.root, config.manifest.path),
+  );
+
   const allowedPaths = getAllowedPaths(config, result);
 
   const path = request.path.slice(1);
@@ -140,6 +142,28 @@ export function getServer(
       .catch(next);
   });
 
+  // Serve the manifest file at the expected URL.
+  app.get('/snap.manifest.json', (_request, response, next) => {
+    response.sendFile(
+      resolvePath(config.server.root, config.manifest.path),
+      {
+        headers: {
+          'Cache-Control': 'no-cache',
+          'Access-Control-Allow-Origin': '*',
+        },
+      },
+
+      // This is complicated to test, since this middleware is only called if
+      // the file exists in the first place.
+      /* istanbul ignore next */
+      (error) => {
+        if (error) {
+          next(error);
+        }
+      },
+    );
+  });
+
   // Serve the static files.
   app.use(
     expressStatic(config.server.root, {

packages/snaps-rollup-plugin/src/plugin.test.ts

@@ -237,7 +237,7 @@ describe('snaps', () => {
     });
 
     expect(mock).toHaveBeenCalledTimes(1);
-    expect(mock).toHaveBeenCalledWith('/', {
+    expect(mock).toHaveBeenCalledWith('/snap.manifest.json', {
       updateAndWriteManifest: true,
       sourceCode: expect.any(String),
     });
@@ -260,7 +260,7 @@ describe('snaps', () => {
     });
 
     expect(mock).toHaveBeenCalledTimes(1);
-    expect(mock).toHaveBeenCalledWith('/', {
+    expect(mock).toHaveBeenCalledWith('/snap.manifest.json', {
       updateAndWriteManifest: false,
       sourceCode: expect.any(String),
     });

packages/snaps-rollup-plugin/src/plugin.ts

@@ -74,13 +74,10 @@ export default function snaps(options?: Partial<Options>): Plugin {
       }
 
       if (defaultOptions.manifestPath) {
-        const { reports } = await checkManifest(
-          pathUtils.dirname(defaultOptions.manifestPath),
-          {
-            updateAndWriteManifest: defaultOptions.writeManifest,
-            sourceCode: await fs.readFile(output.file, 'utf8'),
-          },
-        );
+        const { reports } = await checkManifest(defaultOptions.manifestPath, {
+          updateAndWriteManifest: defaultOptions.writeManifest,
+          sourceCode: await fs.readFile(output.file, 'utf8'),
+        });
 
         const errorsUnfixed = reports
           .filter((report) => report.severity === 'error' && !report.wasFixed)