feat: resolve parent workspace in monorepos workspaces

.eslintrc

@@ -1,4 +1,5 @@
 {
   "extends": "@voxpelli/eslint-config/esm",
-  "root": true
+  "root": true,
+  "ignorePatterns": ["examples/**"]
 }

README.md

@@ -69,9 +69,33 @@ Use [installed-check-core](https://github.com/voxpelli/node-installed-check-core
 ## Workspace options
 
   * `--no-include-workspace-root` – excludes the workspace root package. Negated equivalent of npm's [`--include-workspace-root`](https://docs.npmjs.com/cli/v10/commands/npm-run-script#include-workspace-root)
+  * `--no-parent-workspace` – disables automatic detection and use of parent workspace root for module resolution
   * `--no-workspaces` – excludes workspace packages. Negated equivalent of npm's [`--workspaces`](https://docs.npmjs.com/cli/v10/commands/npm-run-script#workspaces)
   * `--workspace=ARG` / `-w ARG` – excludes all workspace packages not matching these names / paths. Equivalent to npm's [`--workspace` / `-w`](https://docs.npmjs.com/cli/v10/commands/npm-run-script#workspace)
-  * `--workspace-ignore=ARG` – xcludes the specified paths from workspace lookup. (Supports globs)
+  * `--workspace-ignore=ARG` – excludes the specified paths from workspace lookup. (Supports globs)
+
+### Nested workspace support
+
+When running `installed-check` within a workspace that is part of a larger monorepo (e.g., when using `git subtree` or working in a nested monorepo structure), the tool will automatically detect the parent workspace root and include modules from the parent's `node_modules` directory. This ensures that dependencies hosted at the monorepo root level are properly detected and checked.
+
+This behavior is automatic when:
+- No explicit workspace filters are provided (`--workspace`)
+- The `--no-parent-workspace` flag is not used
+
+For example, if you have a structure like:
+```
+/parent-monorepo
+  /node_modules (shared dependencies)
+  /packages
+    /my-workspace
+      /package.json
+```
+
+Running `installed-check` in `/parent-monorepo/packages/my-workspace` will automatically detect the parent monorepo and check dependencies from both the workspace and the parent's `node_modules`.
+
+You can also explicitly specify a path to a workspace within a monorepo, and parent workspace detection will still work:
+
+To disable this behavior, use the `--no-parent-workspace` flag.
 
 ### Additional command line options
 
@@ -80,6 +104,14 @@ Use [installed-check-core](https://github.com/voxpelli/node-installed-check-core
 * `--help` / `-h` – prints help and exits
 * `--version` – prints current version and exits
 
+## Examples
+
+The repository includes practical examples demonstrating `installed-check` usage:
+
+* **[Basic Example](examples/basic/README.md)** – Simple project showing engine range validation
+* **[Monorepo Example](examples/monorepo/README.md)** – Workspace root with dependency issues
+* **[Workspace Example](examples/monorepo/packages/workspace-a/README.md)** – Individual workspace with parent workspace detection
+
 ## Similar modules
 
 * [`knip`](https://github.com/webpro/knip) – finds unused files, dependencies and exports in your JavaScript and TypeScript projects – a great companion module to `installed-check`

cli.js

@@ -1,14 +1,31 @@
 /* eslint-disable no-console, unicorn/no-process-exit */
 
+import { resolve } from 'node:path';
 import chalk from 'chalk';
 import meow from 'meow';
 import { messageWithCauses, stackWithCauses } from 'pony-cause';
 import { installedCheck, ROOT } from 'installed-check-core';
+import resolveWorkspaceRootPkg from 'resolve-workspace-root';
+
+const { resolveWorkspaceRootAsync } = resolveWorkspaceRootPkg;
 
 const EXIT_CODE_ERROR_RESULT = 1;
 const EXIT_CODE_INVALID_INPUT = 2;
 const EXIT_CODE_UNEXPECTED_ERROR = 4;
 
+/**
+ * Log a debug message to stderr if debug mode is enabled
+ *
+ * @param {boolean | undefined} debug
+ * @param {string} label
+ * @param {string} message
+ */
+function debugLog (debug, label, message) {
+  if (debug) {
+    console.error(chalk.blue(label + ':') + ' ' + message);
+  }
+}
+
 const cli = meow(`
   Usage
     $ installed-check <path to module folder>
@@ -30,6 +47,7 @@ const cli = meow(`
 
   Workspace options
     --no-include-workspace-root  Will exclude the workspace root package
+    --no-parent-workspace        Will not detect and use parent workspace root for module resolution
     --no-workspaces              Will exclude workspace packages
     -w ARG, --workspace=ARG      Excludes all workspace packages not matching these names / paths
     --workspace-ignore=ARG       Excludes the specified paths from workspace lookup. (Supports globs)
@@ -52,6 +70,7 @@ const cli = meow(`
     ignore: { shortFlag: 'i', type: 'string', isMultiple: true },
     ignoreDev: { shortFlag: 'd', type: 'boolean' },
     includeWorkspaceRoot: { type: 'boolean', 'default': true },
+    parentWorkspace: { type: 'boolean', 'default': true },
     peerCheck: { shortFlag: 'p', type: 'boolean' },
     strict: { shortFlag: 's', type: 'boolean' },
     verbose: { shortFlag: 'v', type: 'boolean' },
@@ -75,6 +94,7 @@ const {
   engineNoDev, // deprecated
   fix = false,
   includeWorkspaceRoot,
+  parentWorkspace,
   peerCheck,
   strict,
   verbose,
@@ -106,13 +126,59 @@ let checks = [
   ...versionCheck ? /** @type {const} */ (['version']) : [],
 ];
 
+// Detect if we're in a workspace within a larger monorepo
+// If so, use the parent workspace root to enable access to parent's node_modules
+const requestedCwd = resolve(cli.input[0] || process.cwd());
+
+let resolvedCwd = requestedCwd;
+let workspaceFilter = workspace;
+let resolvedIncludeWorkspaceRoot = includeWorkspaceRoot;
+
+// Only detect parent workspace if:
+// - User hasn't explicitly opted out with --no-parent-workspace
+// - User hasn't provided explicit workspace filters (which would be incompatible)
+if (parentWorkspace && !workspace?.length) {
+  debugLog(debug, 'Parent workspace detection', 'Attempting to resolve parent workspace root');
+
+  const parentWorkspaceRoot = await resolveWorkspaceRootAsync(requestedCwd);
+
+  if (parentWorkspaceRoot) {
+    debugLog(debug, 'Parent workspace detection', 'Found parent workspace root: ' + parentWorkspaceRoot);
+  } else {
+    debugLog(debug, 'Parent workspace detection', 'No parent workspace root found');
+  }
+
+  // If we found a parent workspace root different from our requested cwd,
+  // we're in a workspace situation
+  if (parentWorkspaceRoot && parentWorkspaceRoot !== requestedCwd) {
+    // Use the parent workspace root as cwd to get access to its node_modules
+    resolvedCwd = parentWorkspaceRoot;
+
+    // Filter to just the current workspace to avoid checking all workspaces in the parent monorepo
+    workspaceFilter = [requestedCwd];
+
+    // Don't include the workspace root (parent) in checks, only the filtered workspace
+    resolvedIncludeWorkspaceRoot = false;
+
+    debugLog(debug, 'Parent workspace detection', 'Using parent workspace root, filtering to current workspace');
+  } else if (parentWorkspaceRoot === requestedCwd) {
+    debugLog(debug, 'Parent workspace detection', 'Parent workspace root is same as requested cwd, not applying');
+  }
+} else if (debug) {
+  /** @type {string[]} */
+  const reasons = [];
+  if (!parentWorkspace) reasons.push('--no-parent-workspace flag is set');
+  if (workspace?.length) reasons.push('explicit workspace filters provided');
+  debugLog(debug, 'Parent workspace detection', 'Skipped (' + reasons.join(', ') + ')');
+}
+
 /** @type {import('installed-check-core').LookupOptions} */
 const lookupOptions = {
-  cwd: cli.input[0],
+  cwd: resolvedCwd,
   ignorePaths: workspaceIgnore,
-  includeWorkspaceRoot,
+  includeWorkspaceRoot: resolvedIncludeWorkspaceRoot,
   skipWorkspaces: !workspaces,
-  workspace,
+  workspace: workspaceFilter,
 };
 
 /** @type {import('installed-check-core').InstalledCheckOptions} */
@@ -128,9 +194,9 @@ if (checks.length === 0) {
 
 if (debug) {
   const { inspect } = await import('node:util');
-  console.log(chalk.blue('Checks:') + ' ' + inspect(checks, { colors: true, compact: true }));
-  console.log(chalk.blue('Lookup options:') + ' ' + inspect(lookupOptions, { colors: true, compact: true }));
-  console.log(chalk.blue('Check options:') + ' ' + inspect(checkOptions, { colors: true, compact: true }));
+  debugLog(debug, 'Checks', inspect(checks, { colors: true, compact: true }));
+  debugLog(debug, 'Lookup options', inspect(lookupOptions, { colors: true, compact: true }));
+  debugLog(debug, 'Check options', inspect(checkOptions, { colors: true, compact: true }));
 }
 
 try {

examples/.gitignore

@@ -0,0 +1,2 @@
+node_modules/
+package-lock.json

examples/basic/README.md

@@ -0,0 +1,35 @@
+# Basic Example
+
+This is a simple example showing how `installed-check` works with a basic Node.js project.
+
+## What's in This Example
+
+This example demonstrates a common issue - a dependency (`meow`) has a stricter `engines.node` requirement than the package itself:
+- `chalk@^4.0.0` - A popular terminal coloring library
+- `meow@^14.0.0` - A CLI helper library (requires Node >=20, but package specifies >=18.6.0)
+
+## Usage
+
+```bash
+# From the repository root
+cd examples/basic
+npm install
+cd ../..
+
+# Run installed-check
+node cli-wrapper.cjs examples/basic
+```
+
+## Example Output
+
+<!-- BEGIN EXPECTED OUTPUT -->
+```
+Errors:
+
+meow: Narrower "engines.node" is needed: >=20.0.0
+
+Suggestions:
+
+Combined "engines.node" needs to be narrower: >=20.0.0
+```
+<!-- END EXPECTED OUTPUT -->

examples/basic/package.json

@@ -0,0 +1,13 @@
+{
+  "name": "example-basic",
+  "version": "1.0.0",
+  "private": true,
+  "description": "Basic example for installed-check - intentionally has issues for demonstration",
+  "dependencies": {
+    "chalk": "^4.0.0",
+    "meow": "^14.0.0"
+  },
+  "engines": {
+    "node": ">=18.6.0"
+  }
+}

examples/monorepo/README.md

@@ -0,0 +1,50 @@
+# Monorepo Example
+
+This example demonstrates how `installed-check` works with monorepo workspaces.
+
+## Structure
+
+```
+monorepo/
+├── package.json (workspace root with chalk@^4.0.0 and meow@^14.0.0 - has engine issue)
+├── node_modules/ (shared dependencies installed here)
+└── packages/
+    ├── workspace-a/
+    │   └── package.json (depends on chalk@^4.0.0)
+    └── workspace-b/
+        └── package.json (depends on chalk@^4.0.0, has typescript in devDeps)
+```
+
+## Usage
+
+### Running from Monorepo Root
+
+This checks all workspaces at once including the root:
+
+```bash
+# From the repository root
+cd examples/monorepo
+npm install
+cd ../..
+
+# Check the entire monorepo
+node cli-wrapper.cjs examples/monorepo
+```
+
+## Example Output
+
+<!-- BEGIN EXPECTED OUTPUT -->
+```
+Errors:
+
+root: meow: Narrower "engines.node" is needed: >=20.0.0
+
+Suggestions:
+
+root: Combined "engines.node" needs to be narrower: >=20.0.0
+```
+<!-- END EXPECTED OUTPUT -->
+
+### Running from Individual Workspace
+
+See [workspace-a/README.md](./packages/workspace-a/README.md) for examples of running `installed-check` on an individual workspace with automatic parent workspace detection.

examples/monorepo/package.json

@@ -0,0 +1,16 @@
+{
+  "name": "example-monorepo",
+  "version": "1.0.0",
+  "private": true,
+  "description": "Monorepo example for installed-check parent workspace detection",
+  "workspaces": [
+    "packages/*"
+  ],
+  "dependencies": {
+    "chalk": "^4.0.0",
+    "meow": "^14.0.0"
+  },
+  "engines": {
+    "node": ">=18.6.0"
+  }
+}

examples/monorepo/packages/workspace-a/README.md

@@ -0,0 +1,56 @@
+# Workspace A
+
+This workspace is part of the monorepo example and demonstrates automatic parent workspace detection.
+
+## What's in This Workspace
+
+This workspace:
+- Depends on `chalk@^4.0.0` (installed in parent's node_modules)
+- Has a clean configuration with no errors
+
+The parent monorepo root has a `meow` dependency with an engine issue, but that issue does NOT appear when checking this workspace because `includeWorkspaceRoot` is set to `false` when using parent workspace detection.
+
+## Usage
+
+```bash
+# From the repository root
+cd examples/monorepo
+npm install
+cd ../..
+
+# Run installed-check on this workspace
+node cli-wrapper.cjs examples/monorepo/packages/workspace-a
+
+# With debug output
+node cli-wrapper.cjs --debug examples/monorepo/packages/workspace-a
+```
+
+## What Happens
+
+When you run `installed-check` in this workspace:
+1. **Parent detection**: Automatically detects the parent monorepo at `examples/monorepo`
+2. **Module resolution**: Uses the parent's `node_modules` for finding dependencies
+3. **Filtered checking**: Only checks this workspace package, not the parent (includeWorkspaceRoot: false)
+4. **Validation**: Passes cleanly - the root's meow issue is excluded
+
+## Example Output
+
+<!-- BEGIN EXPECTED OUTPUT -->
+```
+
+```
+<!-- END EXPECTED OUTPUT -->
+
+The empty output indicates success - this workspace has no issues, and the parent's issue is excluded.
+
+### Debug Output
+
+When run with `--debug`, you'll see parent workspace detection:
+
+<!-- BEGIN DEBUG OUTPUT -->
+```
+Parent workspace detection: Attempting to resolve parent workspace root
+Parent workspace detection: Found parent workspace root: /absolute/path/to/examples/monorepo
+Parent workspace detection: Using parent workspace root, filtering to current workspace
+```
+<!-- END DEBUG OUTPUT -->

examples/monorepo/packages/workspace-a/package.json

@@ -0,0 +1,12 @@
+{
+  "name": "workspace-a",
+  "version": "1.0.0",
+  "private": true,
+  "description": "Workspace A in monorepo example",
+  "dependencies": {
+    "chalk": "^4.0.0"
+  },
+  "engines": {
+    "node": ">=18.6.0"
+  }
+}

examples/monorepo/packages/workspace-b/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "workspace-b",
+  "version": "1.0.0",
+  "private": true,
+  "description": "Workspace B in monorepo example",
+  "dependencies": {
+    "chalk": "^4.0.0"
+  },
+  "devDependencies": {
+    "typescript": "^5.0.0"
+  },
+  "engines": {
+    "node": ">=18.6.0"
+  }
+}