fix(DryMongoBinary): resolve modulesCache relative to config options package.json

this should help locally installed binaries within a workspace instead of the current run package.

Author: hasezoey

docs/api/config-options.md

@@ -22,6 +22,26 @@ Directory Priority:
 3. `projectRoot/node_modules/.cache/mongodb-binaries` (node-modules cache)
 4. `./mongodb-binaries` (relative to `process.cwd()`)
 
+:::note
+Resolving the `node_modules/.cache` can be rather inconsistent depending on what package manager is used and from where the script is started.
+
+A way to force a more specific `node_modules/.cache` to be used (like a workspace's) is to set the package.json config for mongodb-memory-server (there needs to be at least one key, it does not matter if it is a actual config option or not), see [How to use them in the package.json](#how-to-use-them-in-the-packagejson).
+Example:
+
+```json
+{
+  "name": "workspace",
+  // along with your other workspace keys
+  "config": {
+    "mongodbMemoryServer": {
+      "_": 0
+    }
+  }
+}
+```
+
+:::
+
 Format:
 
 - `/path/to/binary/` (POSIX)

packages/mongodb-memory-server-core/src/util/DryMongoBinary.ts

@@ -1,5 +1,11 @@
 import debug from 'debug';
-import { DEFAULT_VERSION, envToBool, resolveConfig, ResolveConfigVariables } from './resolveConfig';
+import {
+  DEFAULT_VERSION,
+  envToBool,
+  packageJsonPath,
+  resolveConfig,
+  ResolveConfigVariables,
+} from './resolveConfig';
 import {
   assertion,
   checkBinaryPermissions,
@@ -308,6 +314,13 @@ export class DryMongoBinary {
       nodeModulesDLDir = path.resolve(nodeModulesDLDir, '..', '..');
     }
 
+    const configPackagePath = packageJsonPath();
+
+    // use the same "node_modules/.cache" as the package.json that was found for config options, if available
+    if (configPackagePath && (await pathExists(path.resolve(configPackagePath, 'node_modules')))) {
+      nodeModulesDLDir = configPackagePath;
+    }
+
     const tmpModulesCache = findCacheDir({
       name: 'mongodb-memory-server',
       cwd: nodeModulesDLDir,

packages/mongodb-memory-server-core/src/util/__tests__/dryBinary.test.ts

@@ -3,6 +3,7 @@ import { DryMongoBinary } from '../DryMongoBinary';
 import * as path from 'path';
 import { constants, promises as fspromises } from 'fs';
 import { DEFAULT_VERSION, envName, ResolveConfigVariables } from '../resolveConfig';
+import * as resConfig from '../resolveConfig';
 import * as utils from '../utils';
 import * as getOs from '../getos';
 import { LinuxOS, OtherOS } from '../getos';
@@ -140,6 +141,102 @@ describe('DryBinary', () => {
         modulesCache: '', // because not being in an project
       } as binary.DryMongoBinaryPaths);
     });
+
+    it('should resolve modulesCache relative to the package json that has config options', async () => {
+      const workspacePackagePath = path.resolve(tmpDir, 'package.json');
+      const packagePackagePath = path.resolve(tmpDir, 'packages/testy/package.json');
+      await utils.mkdir(path.dirname(packagePackagePath));
+
+      // create the shared workspace package.json
+      await fspromises.writeFile(
+        workspacePackagePath,
+        JSON.stringify({
+          name: 'testw',
+          private: true,
+          devDependencies: {
+            'mongodb-memory-server': '0.0.0',
+          },
+          config: {
+            mongodbMemoryServer: {
+              test: 1,
+            },
+          },
+        })
+      );
+      // emulate having resolved the package.json files and found the above file
+      jest.spyOn(resConfig, 'packageJsonPath').mockReturnValue(path.dirname(workspacePackagePath));
+      // emulate having run "npm i" / "yarn install"
+      await utils.mkdir(path.resolve(path.dirname(workspacePackagePath), 'node_modules'));
+
+      // create the package's package.json
+      await fspromises.writeFile(
+        packagePackagePath,
+        JSON.stringify({
+          name: 'testp',
+          // no custom configuration
+        })
+      );
+
+      process.chdir(path.dirname(packagePackagePath));
+
+      const returnValue = await binary.DryMongoBinary.generatePaths(opts);
+      expect(returnValue).toStrictEqual({
+        resolveConfig: '', // empty because not having an extra config value
+        relative: path.resolve(path.dirname(packagePackagePath), 'mongodb-binaries', binaryName),
+        homeCache: path.resolve(tmpDir, 'homedir/.cache/mongodb-binaries', binaryName),
+        modulesCache: path.resolve(
+          path.dirname(workspacePackagePath),
+          'node_modules/.cache/mongodb-memory-server',
+          binaryName
+        ),
+      } as binary.DryMongoBinaryPaths);
+    });
+
+    it('should resolve modulesCache relative to cwd if no package.json with config options are found', async () => {
+      const workspacePackagePath = path.resolve(tmpDir, 'package.json');
+      const packagePackagePath = path.resolve(tmpDir, 'packages/testy/package.json');
+      await utils.mkdir(path.dirname(packagePackagePath));
+
+      // create the shared workspace package.json
+      await fspromises.writeFile(
+        workspacePackagePath,
+        JSON.stringify({
+          name: 'testw',
+          private: true,
+          devDependencies: {
+            'mongodb-memory-server': '0.0.0',
+          },
+          // no custom configuration
+        })
+      );
+      // emulate having resolved the package.json files and found the above file
+      jest.spyOn(resConfig, 'packageJsonPath').mockReturnValue(undefined);
+      // emulate having run "npm i" / "yarn install"
+      await utils.mkdir(path.resolve(path.dirname(workspacePackagePath), 'node_modules'));
+
+      // create the package's package.json
+      await fspromises.writeFile(
+        packagePackagePath,
+        JSON.stringify({
+          name: 'testp',
+          // no custom configuration
+        })
+      );
+
+      process.chdir(path.dirname(packagePackagePath));
+
+      const returnValue = await binary.DryMongoBinary.generatePaths(opts);
+      expect(returnValue).toStrictEqual({
+        resolveConfig: '', // empty because not having an extra config value
+        relative: path.resolve(path.dirname(packagePackagePath), 'mongodb-binaries', binaryName),
+        homeCache: path.resolve(tmpDir, 'homedir/.cache/mongodb-binaries', binaryName),
+        modulesCache: path.resolve(
+          path.dirname(packagePackagePath),
+          'node_modules/.cache/mongodb-memory-server',
+          binaryName
+        ),
+      } as binary.DryMongoBinaryPaths);
+    });
   });
 
   describe('getBinaryName', () => {

packages/mongodb-memory-server-core/src/util/resolveConfig.ts

@@ -143,6 +143,14 @@ export function resolveConfig(variableName: ResolveConfigVariables): string | un
   )?.toString();
 }
 
+/**
+ * Get the directory path of the `package.json` with config options, if available
+ * @returns The directory of the `package.json`, otherwise `undefined`
+ */
+export function packageJsonPath(): string | undefined {
+  return packagejson?.filePath;
+}
+
 export default resolveConfig;
 
 /**