feat: automatically detect workspace roots

lib/index.js

@@ -3,6 +3,8 @@ const walkUp = require('walk-up-path')
 const ini = require('ini')
 const nopt = require('nopt')
 const mkdirp = require('mkdirp-infer-owner')
+const mapWorkspaces = require('@npmcli/map-workspaces')
+const rpj = require('read-package-json-fast')
 
 /* istanbul ignore next */
 const myUid = process.getuid && process.getuid()
@@ -543,23 +545,65 @@ class Config {
       return
     }
 
+    const cliWorkspaces = this[_get]('workspaces', 'cli')
+
     for (const p of walkUp(this.cwd)) {
-      // walk up until we have a nm dir or a pj file
-      const hasAny = (await Promise.all([
-        stat(resolve(p, 'node_modules'))
-          .then(st => st.isDirectory())
-          .catch(() => false),
-        stat(resolve(p, 'package.json'))
-          .then(st => st.isFile())
-          .catch(() => false),
-      ])).some(is => is)
-      if (hasAny) {
+      const hasNodeModules = await stat(resolve(p, 'node_modules'))
+        .then((st) => st.isDirectory())
+        .catch(() => false)
+
+      const hasPackageJson = await stat(resolve(p, 'package.json'))
+        .then((st) => st.isFile())
+        .catch(() => false)
+
+      if (!this.localPrefix && (hasNodeModules || hasPackageJson)) {
         this.localPrefix = p
-        return
+
+        // if workspaces are disabled, return now
+        if (cliWorkspaces === false) {
+          return
+        }
+
+        // otherwise, continue the loop
+        continue
+      }
+
+      if (this.localPrefix && hasPackageJson) {
+        // if we already set localPrefix but this dir has a package.json
+        // then we need to see if `p` is a workspace root by reading its package.json
+        // however, if reading it fails then we should just move on
+        const pkg = await rpj(resolve(p, 'package.json')).catch(() => false)
+        if (!pkg) {
+          continue
+        }
+
+        const workspaces = await mapWorkspaces({ cwd: p, pkg })
+        for (const w of workspaces.values()) {
+          if (w === this.localPrefix) {
+            // see if there's a .npmrc file in the workspace, if so log a warning
+            const hasNpmrc = await stat(resolve(this.localPrefix, '.npmrc'))
+              .then((st) => st.isFile())
+              .catch(() => false)
+
+            if (hasNpmrc) {
+              this.log.warn(`ignoring workspace config at ${this.localPrefix}/.npmrc`)
+            }
+
+            // set the workspace in the default layer, which allows it to be overridden easily
+            const { data } = this.data.get('default')
+            data.workspace = [this.localPrefix]
+            this.localPrefix = p
+            this.log.info(`found workspace root at ${this.localPrefix}`)
+            // we found a root, so we return now
+            return
+          }
+        }
       }
     }
 
-    this.localPrefix = this.cwd
+    if (!this.localPrefix) {
+      this.localPrefix = this.cwd
+    }
   }
 
   loadUserConfig () {