fix(workspaces): explicitly error in global mode

Also includes a preliminary refactor to consolidate workspace logic now
that every command that supports workspaces has it implemented.

PR-URL: https://github.com/npm/cli/pull/3417
Credit: @wraithgar
Close: #3417
Reviewed-by: @ruyadorno

30 files changed, 139 insertions, 101 deletions

diff --git a/lib/audit.js b/lib/audit.js
index a97fd9b30..54480d1f0 100644
--- a/lib/audit.js
+++ b/lib/audit.js
@@ -58,7 +58,7 @@ class Audit extends ArboristWorkspaceCmd {
       audit: true,
       path: this.npm.prefix,
       reporter,
-      workspaces: this.workspaces,
+      workspaces: this.workspaceNames,
     }
 
     const arb = new Arborist(opts)
diff --git a/lib/base-command.js b/lib/base-command.js
index 843fb2d4b..4077733a9 100644
--- a/lib/base-command.js
+++ b/lib/base-command.js
@@ -1,6 +1,7 @@
 // Base class for npm.commands[cmd]
 const usageUtil = require('./utils/usage.js')
 const ConfigDefinitions = require('./utils/config/definitions.js')
+const getWorkspaces = require('./workspaces/get-workspaces.js')
 
 class BaseCommand {
   constructor (npm) {
@@ -72,5 +73,13 @@ class BaseCommand {
       { code: 'ENOWORKSPACES' }
     )
   }
+
+  async setWorkspaces (filters) {
+    // TODO npm guards workspaces/global mode so we should use this.npm.prefix?
+    const ws = await getWorkspaces(filters, { path: this.npm.localPrefix })
+    this.workspaces = ws
+    this.workspaceNames = [...ws.keys()]
+    this.workspacePaths = [...ws.values()]
+  }
 }
 module.exports = BaseCommand
diff --git a/lib/ci.js b/lib/ci.js
index 3a2a2b316..3ff4b65ba 100644
--- a/lib/ci.js
+++ b/lib/ci.js
@@ -55,7 +55,7 @@ class CI extends ArboristWorkspaceCmd {
       path: where,
       log: this.npm.log,
       save: false, // npm ci should never modify the lockfile or package.json
-      workspaces: this.workspaces,
+      workspaces: this.workspaceNames,
     }
 
     const arb = new Arborist(opts)
diff --git a/lib/dedupe.js b/lib/dedupe.js
index 9a58316b8..aaa7a30d1 100644
--- a/lib/dedupe.js
+++ b/lib/dedupe.js
@@ -50,7 +50,7 @@ class Dedupe extends ArboristWorkspaceCmd {
       log: this.npm.log,
       path: where,
       dryRun,
-      workspaces: this.workspaces,
+      workspaces: this.workspaceNames,
     }
     const arb = new Arborist(opts)
     await arb.dedupe(opts)
diff --git a/lib/diff.js b/lib/diff.js
index d315551d4..01658c466 100644
--- a/lib/diff.js
+++ b/lib/diff.js
@@ -8,7 +8,6 @@ const npmlog = require('npmlog')
 const pacote = require('pacote')
 const pickManifest = require('npm-pick-manifest')
 
-const getWorkspaces = require('./workspaces/get-workspaces.js')
 const readPackageName = require('./utils/read-package-name.js')
 const BaseCommand = require('./base-command.js')
 
@@ -90,9 +89,8 @@ class Diff extends BaseCommand {
   }
 
   async diffWorkspaces (args, filters) {
-    const workspaces =
-      await getWorkspaces(filters, { path: this.npm.localPrefix })
-    for (const workspacePath of workspaces.values()) {
+    await this.setWorkspaces(filters)
+    for (const workspacePath of this.workspacePaths) {
       this.top = workspacePath
       this.prefix = workspacePath
       await this.diff(args)
@@ -104,7 +102,6 @@ class Diff extends BaseCommand {
   async packageName (path) {
     let name
     try {
-      // TODO this won't work as expected in global mode
       name = await readPackageName(this.prefix)
     } catch (e) {
       npmlog.verbose('diff', 'could not read project dir package.json')
diff --git a/lib/dist-tag.js b/lib/dist-tag.js
index 11b1ad931..e32dcf61f 100644
--- a/lib/dist-tag.js
+++ b/lib/dist-tag.js
@@ -5,7 +5,6 @@ const semver = require('semver')
 
 const otplease = require('./utils/otplease.js')
 const readPackageName = require('./utils/read-package-name.js')
-const getWorkspaces = require('./workspaces/get-workspaces.js')
 const BaseCommand = require('./base-command.js')
 
 class DistTag extends BaseCommand {
@@ -180,10 +179,9 @@ class DistTag extends BaseCommand {
   }
 
   async listWorkspaces (filters) {
-    const workspaces =
-      await getWorkspaces(filters, { path: this.npm.localPrefix })
+    await this.setWorkspaces(filters)
 
-    for (const [name] of workspaces) {
+    for (const name of this.workspaceNames) {
       try {
         this.npm.output(`${name}:`)
         await this.list(npa(name), this.npm.flatOptions)
diff --git a/lib/docs.js b/lib/docs.js
index 24bbe9c85..69a19c35c 100644
--- a/lib/docs.js
+++ b/lib/docs.js
@@ -2,7 +2,6 @@ const log = require('npmlog')
 const pacote = require('pacote')
 const openUrl = require('./utils/open-url.js')
 const hostedFromMani = require('./utils/hosted-git-info-from-manifest.js')
-const getWorkspaces = require('./workspaces/get-workspaces.js')
 
 const BaseCommand = require('./base-command.js')
 class Docs extends BaseCommand {
@@ -42,9 +41,8 @@ class Docs extends BaseCommand {
   }
 
   async docsWorkspaces (args, filters) {
-    const workspaces =
-      await getWorkspaces(filters, { path: this.npm.localPrefix })
-    return this.docs([...workspaces.values()])
+    await this.setWorkspaces(filters)
+    return this.docs(this.workspacePaths)
   }
 
   async getDocs (pkg) {
diff --git a/lib/exec.js b/lib/exec.js
index 8a87615d9..7e5f6886a 100644
--- a/lib/exec.js
+++ b/lib/exec.js
@@ -1,7 +1,6 @@
 const libexec = require('libnpmexec')
 const BaseCommand = require('./base-command.js')
 const getLocationMsg = require('./exec/get-workspace-location-msg.js')
-const getWorkspaces = require('./workspaces/get-workspaces.js')
 
 // it's like this:
 //
@@ -105,16 +104,15 @@ class Exec extends BaseCommand {
   }
 
   async _execWorkspaces (args, filters) {
-    const workspaces =
-      await getWorkspaces(filters, { path: this.npm.localPrefix })
+    await this.setWorkspaces(filters)
     const color = this.npm.config.get('color')
 
-    for (const workspacePath of workspaces.values()) {
-      const locationMsg = await getLocationMsg({ color, path: workspacePath })
+    for (const path of this.workspacePaths) {
+      const locationMsg = await getLocationMsg({ color, path })
       await this._exec(args, {
         locationMsg,
-        path: workspacePath,
-        runPath: workspacePath,
+        path,
+        runPath: path,
       })
     }
   }
diff --git a/lib/explain.js b/lib/explain.js
index de04c6985..7d785d7bf 100644
--- a/lib/explain.js
+++ b/lib/explain.js
@@ -46,8 +46,8 @@ class Explain extends ArboristWorkspaceCmd {
     const arb = new Arborist({ path: this.npm.prefix, ...this.npm.flatOptions })
     const tree = await arb.loadActual()
 
-    if (this.workspaces && this.workspaces.length)
-      this.filterSet = arb.workspaceDependencySet(tree, this.workspaces)
+    if (this.workspaceNames && this.workspaceNames.length)
+      this.filterSet = arb.workspaceDependencySet(tree, this.workspaceNames)
 
     const nodes = new Set()
     for (const arg of args) {
diff --git a/lib/fund.js b/lib/fund.js
index 55d2f65dc..92580a756 100644
--- a/lib/fund.js
+++ b/lib/fund.js
@@ -95,7 +95,7 @@ class Fund extends ArboristWorkspaceCmd {
     const fundingInfo = getFundingInfo(tree, {
       ...this.flatOptions,
       log: this.npm.log,
-      workspaces: this.workspaces,
+      workspaces: this.workspaceNames,
     })
 
     if (this.npm.config.get('json'))
diff --git a/lib/install.js b/lib/install.js
index 7c5f55bb9..661176397 100644
--- a/lib/install.js
+++ b/lib/install.js
@@ -144,7 +144,7 @@ class Install extends ArboristWorkspaceCmd {
       auditLevel: null,
       path: where,
       add: args,
-      workspaces: this.workspaces,
+      workspaces: this.workspaceNames,
     }
     const arb = new Arborist(opts)
     await arb.reify(opts)
diff --git a/lib/link.js b/lib/link.js
index d6abf1397..febd90871 100644
--- a/lib/link.js
+++ b/lib/link.js
@@ -146,7 +146,7 @@ class Link extends ArboristWorkspaceCmd {
       log: this.npm.log,
       add: names.map(l => `file:${resolve(globalTop, 'node_modules', l)}`),
       save,
-      workspaces: this.workspaces,
+      workspaces: this.workspaceNames,
     })
 
     await reifyFinish(this.npm, localArb)
diff --git a/lib/ls.js b/lib/ls.js
index d92b73ddf..78263554c 100644
--- a/lib/ls.js
+++ b/lib/ls.js
@@ -94,8 +94,8 @@ class LS extends ArboristWorkspaceCmd {
     // We only have to filter the first layer of edges, so we don't
     // explore anything that isn't part of the selected workspace set.
     let wsNodes
-    if (this.workspaces && this.workspaces.length)
-      wsNodes = arb.workspaceNodes(tree, this.workspaces)
+    if (this.workspaceNames && this.workspaceNames.length)
+      wsNodes = arb.workspaceNodes(tree, this.workspaceNames)
     const filterBySelectedWorkspaces = edge => {
       if (!wsNodes || !wsNodes.length)
         return true
diff --git a/lib/npm.js b/lib/npm.js
index 5f8b2ff3d..937459501 100644
--- a/lib/npm.js
+++ b/lib/npm.js
@@ -108,6 +108,9 @@ const npm = module.exports = new class extends EventEmitter {
       this.output(impl.usage)
       cb()
     } else if (filterByWorkspaces) {
+      if (this.config.get('global'))
+        return cb(new Error('Workspaces not supported for global packages'))
+
       impl.execWorkspaces(args, this.config.get('workspace'), er => {
         process.emit('timeEnd', `command:${cmd}`)
         cb(er)
diff --git a/lib/outdated.js b/lib/outdated.js
index 1be92b934..9d60d143d 100644
--- a/lib/outdated.js
+++ b/lib/outdated.js
@@ -59,8 +59,10 @@ class Outdated extends ArboristWorkspaceCmd {
     this.list = []
     this.tree = await arb.loadActual()
 
-    if (this.workspaces && this.workspaces.length)
-      this.filterSet = arb.workspaceDependencySet(this.tree, this.workspaces)
+    if (this.workspaceNames && this.workspaceNames.length) {
+      this.filterSet =
+        arb.workspaceDependencySet(this.tree, this.workspaceNames)
+    }
 
     if (args.length !== 0) {
       // specific deps
diff --git a/lib/pack.js b/lib/pack.js
index 52d4c3e7f..f4364d290 100644
--- a/lib/pack.js
+++ b/lib/pack.js
@@ -3,7 +3,6 @@ const log = require('npmlog')
 const pacote = require('pacote')
 const libpack = require('libnpmpack')
 const npa = require('npm-package-arg')
-const getWorkspaces = require('./workspaces/get-workspaces.js')
 
 const { getContents, logTar } = require('./utils/tar.js')
 
@@ -97,9 +96,8 @@ class Pack extends BaseCommand {
       return this.pack(args)
     }
 
-    const workspaces =
-      await getWorkspaces(filters, { path: this.npm.localPrefix })
-    return this.pack([...workspaces.values(), ...args.filter(a => a !== '.')])
+    await this.setWorkspaces(filters)
+    return this.pack([...this.workspacePaths, ...args.filter(a => a !== '.')])
   }
 }
 module.exports = Pack
diff --git a/lib/prune.js b/lib/prune.js
index a90e75954..a91276fc4 100644
--- a/lib/prune.js
+++ b/lib/prune.js
@@ -34,7 +34,7 @@ class Prune extends ArboristWorkspaceCmd {
       ...this.npm.flatOptions,
       path: where,
       log: this.npm.log,
-      workspaces: this.workspaces,
+      workspaces: this.workspaceNames,
     }
     const arb = new Arborist(opts)
     await arb.prune(opts)
diff --git a/lib/publish.js b/lib/publish.js
index 3cb8b0627..f35388a30 100644
--- a/lib/publish.js
+++ b/lib/publish.js
@@ -11,7 +11,6 @@ const chalk = require('chalk')
 
 const otplease = require('./utils/otplease.js')
 const { getContents, logTar } = require('./utils/tar.js')
-const getWorkspaces = require('./workspaces/get-workspaces.js')
 
 // for historical reasons, publishConfig in package.json can contain ANY config
 // keys that npm supports in .npmrc files and elsewhere.  We *may* want to
@@ -138,7 +137,7 @@ class Publish extends BaseCommand {
       })
     }
 
-    if (!this.workspaces) {
+    if (!this.suppressOutput) {
       if (!silent && json)
         this.npm.output(JSON.stringify(pkgContents, null, 2))
       else if (!silent)
@@ -150,17 +149,16 @@ class Publish extends BaseCommand {
 
   async publishWorkspaces (args, filters) {
     // Suppresses JSON output in publish() so we can handle it here
-    this.workspaces = true
+    this.suppressOutput = true
 
     const results = {}
     const json = this.npm.config.get('json')
     const silent = log.level === 'silent'
     const noop = a => a
     const color = this.npm.color ? chalk : { green: noop, bold: noop }
-    const workspaces =
-      await getWorkspaces(filters, { path: this.npm.localPrefix })
+    await this.setWorkspaces(filters)
 
-    for (const [name, workspace] of workspaces.entries()) {
+    for (const [name, workspace] of this.workspaces.entries()) {
       let pkgContents
       try {
         pkgContents = await this.publish([workspace])
diff --git a/lib/rebuild.js b/lib/rebuild.js
index ef88dc516..9aa0e27f8 100644
--- a/lib/rebuild.js
+++ b/lib/rebuild.js
@@ -47,7 +47,7 @@ class Rebuild extends ArboristWorkspaceCmd {
       ...this.npm.flatOptions,
       path: where,
       // TODO when extending ReifyCmd
-      // workspaces: this.workspaces,
+      // workspaces: this.workspaceNames,
     })
 
     if (args.length) {
diff --git a/lib/repo.js b/lib/repo.js
index 645c0eeae..e0172d01f 100644
--- a/lib/repo.js
+++ b/lib/repo.js
@@ -1,6 +1,5 @@
 const log = require('npmlog')
 const pacote = require('pacote')
-const getWorkspaces = require('./workspaces/get-workspaces.js')
 const { URL } = require('url')
 
 const hostedFromMani = require('./utils/hosted-git-info-from-manifest.js')
@@ -44,9 +43,8 @@ class Repo extends BaseCommand {
   }
 
   async repoWorkspaces (args, filters) {
-    const workspaces =
-      await getWorkspaces(filters, { path: this.npm.localPrefix })
-    return this.repo([...workspaces.values()])
+    await this.setWorkspaces(filters)
+    return this.repo(this.workspacePaths)
   }
 
   async get (pkg) {
diff --git a/lib/run-script.js b/lib/run-script.js
index ec1042828..b94d2fce0 100644
--- a/lib/run-script.js
+++ b/lib/run-script.js
@@ -6,7 +6,6 @@ const rpj = require('read-package-json-fast')
 const log = require('npmlog')
 const didYouMean = require('./utils/did-you-mean.js')
 const isWindowsShell = require('./utils/is-windows-shell.js')
-const getWorkspaces = require('./workspaces/get-workspaces.js')
 
 const cmdList = [
   'publish',
@@ -195,10 +194,9 @@ class RunScript extends BaseCommand {
 
   async runWorkspaces (args, filters) {
     const res = []
-    const workspaces =
-      await getWorkspaces(filters, { path: this.npm.localPrefix })
+    await this.setWorkspaces(filters)
 
-    for (const workspacePath of workspaces.values()) {
+    for (const workspacePath of this.workspacePaths) {
       const pkg = await rpj(`${workspacePath}/package.json`)
       const runResult = await this.run(args, {
         path: workspacePath,
@@ -227,15 +225,14 @@ class RunScript extends BaseCommand {
   }
 
   async listWorkspaces (args, filters) {
-    const workspaces =
-      await getWorkspaces(filters, { path: this.npm.localPrefix })
+    await this.setWorkspaces(filters)
 
     if (log.level === 'silent')
       return
 
     if (this.npm.config.get('json')) {
       const res = {}
-      for (const workspacePath of workspaces.values()) {
+      for (const workspacePath of this.workspacePaths) {
         const { scripts, name } = await rpj(`${workspacePath}/package.json`)
         res[name] = { ...scripts }
       }
@@ -244,7 +241,7 @@ class RunScript extends BaseCommand {
     }
 
     if (this.npm.config.get('parseable')) {
-      for (const workspacePath of workspaces.values()) {
+      for (const workspacePath of this.workspacePaths) {
         const { scripts, name } = await rpj(`${workspacePath}/package.json`)
         for (const [script, cmd] of Object.entries(scripts || {}))
           this.npm.output(`${name}:${script}:${cmd}`)
@@ -252,7 +249,7 @@ class RunScript extends BaseCommand {
       return
     }
 
-    for (const workspacePath of workspaces.values())
+    for (const workspacePath of this.workspacePaths)
       await this.list(args, workspacePath)
   }
 }
diff --git a/lib/set-script.js b/lib/set-script.js
index b31e123be..cd01e28b5 100644
--- a/lib/set-script.js
+++ b/lib/set-script.js
@@ -3,7 +3,6 @@ const fs = require('fs')
 const parseJSON = require('json-parse-even-better-errors')
 const rpj = require('read-package-json-fast')
 const { resolve } = require('path')
-const getWorkspaces = require('./workspaces/get-workspaces.js')
 
 const BaseCommand = require('./base-command.js')
 class SetScript extends BaseCommand {
@@ -47,28 +46,27 @@ class SetScript extends BaseCommand {
   }
 
   exec (args, cb) {
-    this.set(args).then(() => cb()).catch(cb)
+    this.setScript(args).then(() => cb()).catch(cb)
   }
 
-  async set (args) {
+  async setScript (args) {
     this.validate(args)
-    const warn = this.setScript(this.npm.localPrefix, args[0], args[1])
+    const warn = this.doSetScript(this.npm.localPrefix, args[0], args[1])
     if (warn)
       log.warn('set-script', `Script "${args[0]}" was overwritten`)
   }
 
   execWorkspaces (args, filters, cb) {
-    this.setWorkspaces(args, filters).then(() => cb()).catch(cb)
+    this.setScriptWorkspaces(args, filters).then(() => cb()).catch(cb)
   }
 
-  async setWorkspaces (args, filters) {
+  async setScriptWorkspaces (args, filters) {
     this.validate(args)
-    const workspaces =
-      await getWorkspaces(filters, { path: this.npm.localPrefix })
+    await this.setWorkspaces(filters)
 
-    for (const [name, path] of workspaces) {
+    for (const [name, path] of this.workspaces) {
       try {
-        const warn = this.setScript(path, args[0], args[1])
+        const warn = this.doSetScript(path, args[0], args[1])
         if (warn) {
           log.warn('set-script', `Script "${args[0]}" was overwritten`)
           log.warn(`  in workspace: ${name}`)
@@ -86,7 +84,7 @@ class SetScript extends BaseCommand {
   // returns a Boolean that will be true if
   // the requested script was overwritten
   // and false if it was set as a new script
-  setScript (path, name, value) {
+  doSetScript (path, name, value) {
     // Set the script
     let manifest
     let warn = false
diff --git a/lib/uninstall.js b/lib/uninstall.js
index cbbc62c2a..fbb2cef0f 100644
--- a/lib/uninstall.js
+++ b/lib/uninstall.js
@@ -66,7 +66,7 @@ class Uninstall extends ArboristWorkspaceCmd {
       path,
       log: this.npm.log,
       rm: args,
-      workspaces: this.workspaces,
+      workspaces: this.workspaceNames,
     }
     const arb = new Arborist(opts)
     await arb.reify(opts)
diff --git a/lib/unpublish.js b/lib/unpublish.js
index 1571fd88e..32a634013 100644
--- a/lib/unpublish.js
+++ b/lib/unpublish.js
@@ -6,7 +6,6 @@ const npmFetch = require('npm-registry-fetch')
 const libunpub = require('libnpmpublish').unpublish
 const readJson = util.promisify(require('read-package-json'))
 
-const getWorkspaces = require('./workspaces/get-workspaces.js')
 const otplease = require('./utils/otplease.js')
 const getIdentity = require('./utils/get-identity.js')
 
@@ -129,8 +128,7 @@ class Unpublish extends BaseCommand {
   }
 
   async unpublishWorkspaces (args, filters) {
-    const workspaces =
-      await getWorkspaces(filters, { path: this.npm.localPrefix })
+    await this.setWorkspaces(filters)
 
     const force = this.npm.config.get('force')
     if (!force) {
@@ -140,7 +138,7 @@ class Unpublish extends BaseCommand {
       )
     }
 
-    for (const [name] of workspaces.entries())
+    for (const name of this.workspaceNames)
       await this.unpublish([name])
   }
 }
diff --git a/lib/update.js b/lib/update.js
index 3cdeb8ea7..393c8f0f6 100644
--- a/lib/update.js
+++ b/lib/update.js
@@ -66,7 +66,7 @@ class Update extends ArboristWorkspaceCmd {
       ...this.npm.flatOptions,
       log: this.npm.log,
       path: where,
-      workspaces: this.workspaces,
+      workspaces: this.workspaceNames,
     })
 
     await arb.reify({ update })
diff --git a/lib/version.js b/lib/version.js
index 3ef3801e7..f3680fe8b 100644
--- a/lib/version.js
+++ b/lib/version.js
@@ -3,7 +3,6 @@ const { resolve } = require('path')
 const { promisify } = require('util')
 const readFile = promisify(require('fs').readFile)
 
-const getWorkspaces = require('./workspaces/get-workspaces.js')
 const BaseCommand = require('./base-command.js')
 
 class Version extends BaseCommand {
@@ -93,9 +92,8 @@ class Version extends BaseCommand {
 
   async changeWorkspaces (args, filters) {
     const prefix = this.npm.config.get('tag-version-prefix')
-    const workspaces =
-      await getWorkspaces(filters, { path: this.npm.localPrefix })
-    for (const [name, path] of workspaces) {
+    await this.setWorkspaces(filters)
+    for (const [name, path] of this.workspaces) {
       this.npm.output(name)
       const version = await libnpmversion(args[0], {
         ...this.npm.flatOptions,
@@ -128,11 +126,10 @@ class Version extends BaseCommand {
 
   async listWorkspaces (filters) {
     const results = {}
-    const workspaces =
-      await getWorkspaces(filters, { path: this.npm.localPrefix })
-    for (const [, path] of workspaces) {
+    await this.setWorkspaces(filters)
+    for (const path of this.workspacePaths) {
       const pj = resolve(path, 'package.json')
-      // getWorkspaces has already parsed this so we know it won't error
+      // setWorkspaces has already parsed package.json so we know it won't error
       const pkg = await readFile(pj, 'utf8')
         .then(data => JSON.parse(data))
 
diff --git a/lib/view.js b/lib/view.js
index 9cc1aed91..788df3ed0 100644
--- a/lib/view.js
+++ b/lib/view.js
@@ -13,7 +13,6 @@ const semver = require('semver')
 const style = require('ansistyles')
 const { inspect, promisify } = require('util')
 const { packument } = require('pacote')
-const getWorkspaces = require('./workspaces/get-workspaces.js')
 
 const readFile = promisify(fs.readFile)
 const readJson = async file => jsonParse(await readFile(file, 'utf8'))
@@ -160,10 +159,9 @@ class View extends BaseCommand {
       args = [''] // getData relies on this
     }
     const results = {}
-    const workspaces =
-      await getWorkspaces(filters, { path: this.npm.localPrefix })
-    for (const workspace of [...workspaces.entries()]) {
-      const wsPkg = `${workspace[0]}${pkg.slice(1)}`
+    await this.setWorkspaces(filters)
+    for (const name of this.workspaceNames) {
+      const wsPkg = `${name}${pkg.slice(1)}`
       const [pckmnt, data] = await this.getData(wsPkg, args)
 
       let reducedData = data.reduce(reducer, {})
@@ -177,7 +175,7 @@ class View extends BaseCommand {
         if (wholePackument)
           data.map((v) => this.prettyView(pckmnt, v[Object.keys(v)[0]]['']))
         else {
-          console.log(`${workspace[0]}:`)
+          console.log(`${name}:`)
           const msg = await this.jsonData(reducedData, pckmnt._id)
           if (msg !== '')
             console.log(msg)
@@ -185,7 +183,7 @@ class View extends BaseCommand {
       } else {
         const msg = await this.jsonData(reducedData, pckmnt._id)
         if (msg !== '')
-          results[workspace[0]] = JSON.parse(msg)
+          results[name] = JSON.parse(msg)
       }
     }
     if (Object.keys(results).length > 0)
diff --git a/lib/workspaces/arborist-cmd.js b/lib/workspaces/arborist-cmd.js
index 337e7f9d8..cb6b66b8c 100644
--- a/lib/workspaces/arborist-cmd.js
+++ b/lib/workspaces/arborist-cmd.js
@@ -3,7 +3,6 @@
 // be able to run a filtered Arborist.reify() at some point.
 
 const BaseCommand = require('../base-command.js')
-const getWorkspaces = require('./get-workspaces.js')
 class ArboristCmd extends BaseCommand {
   /* istanbul ignore next - see test/lib/load-all-commands.js */
   static get params () {
@@ -14,10 +13,8 @@ class ArboristCmd extends BaseCommand {
   }
 
   execWorkspaces (args, filters, cb) {
-    getWorkspaces(filters, { path: this.npm.localPrefix })
-      .then(workspaces => {
-        this.workspaces = [...workspaces.keys()]
-        this.workspacePaths = [...workspaces.values()]
+    this.setWorkspaces(filters)
+      .then(() => {
         this.exec(args, cb)
       })
       .catch(er => cb(er))
diff --git a/test/lib/npm.js b/test/lib/npm.js
index 6f8f8936d..6909c43e4 100644
--- a/test/lib/npm.js
+++ b/test/lib/npm.js
@@ -355,7 +355,7 @@ t.test('npm.load', t => {
     await new Promise((res) => setTimeout(res))
   })
 
-  t.test('workpaces-aware configs and commands', async t => {
+  t.test('workspace-aware configs and commands', async t => {
     const dir = t.testdir({
       packages: {
         a: {
@@ -438,6 +438,60 @@ t.test('npm.load', t => {
     })
   })
 
+  t.test('workspaces in global mode', async t => {
+    const dir = t.testdir({
+      packages: {
+        a: {
+          'package.json': JSON.stringify({
+            name: 'a',
+            version: '1.0.0',
+            scripts: { test: 'echo test a' },
+          }),
+        },
+        b: {
+          'package.json': JSON.stringify({
+            name: 'b',
+            version: '1.0.0',
+            scripts: { test: 'echo test b' },
+          }),
+        },
+      },
+      'package.json': JSON.stringify({
+        name: 'root',
+        version: '1.0.0',
+        workspaces: ['./packages/*'],
+      }),
+    })
+    const { execPath } = process
+    freshConfig({
+      argv: [
+        execPath,
+        process.argv[1],
+        '--userconfig',
+        resolve(dir, '.npmrc'),
+        '--color',
+        'false',
+        '--workspaces',
+        '--global',
+        'true',
+      ],
+    })
+    await npm.load(er => {
+      if (er)
+        throw er
+    })
+    npm.localPrefix = dir
+    await new Promise((res, rej) => {
+      // verify that calling the command with a short name still sets
+      // the npm.command property to the full canonical name of the cmd.
+      npm.command = null
+      npm.commands.run([], er => {
+        t.match(er, /Workspaces not supported for global packages/)
+        res()
+      })
+    })
+  })
+
   t.end()
 })
 
diff --git a/test/lib/workspaces/arborist-cmd.js b/test/lib/workspaces/arborist-cmd.js
index 740ddb1ff..75ac8f4eb 100644
--- a/test/lib/workspaces/arborist-cmd.js
+++ b/test/lib/workspaces/arborist-cmd.js
@@ -49,7 +49,7 @@ t.test('arborist-cmd', async t => {
 
   // check filtering for a single workspace name
   cmd.exec = function (args, cb) {
-    t.same(this.workspaces, ['a'], 'should set array with single ws name')
+    t.same(this.workspaceNames, ['a'], 'should set array with single ws name')
     t.same(args, ['foo'], 'should get received args')
     cb()
   }
@@ -59,7 +59,7 @@ t.test('arborist-cmd', async t => {
 
   // check filtering single workspace by path
   cmd.exec = function (args, cb) {
-    t.same(this.workspaces, ['a'],
+    t.same(this.workspaceNames, ['a'],
       'should set array with single ws name from path')
     cb()
   }
@@ -69,7 +69,7 @@ t.test('arborist-cmd', async t => {
 
   // check filtering single workspace by full path
   cmd.exec = function (args, cb) {
-    t.same(this.workspaces, ['a'],
+    t.same(this.workspaceNames, ['a'],
       'should set array with single ws name from full path')
     cb()
   }
@@ -79,7 +79,7 @@ t.test('arborist-cmd', async t => {
 
   // filtering multiple workspaces by name
   cmd.exec = function (args, cb) {
-    t.same(this.workspaces, ['a', 'c'],
+    t.same(this.workspaceNames, ['a', 'c'],
       'should set array with multiple listed ws names')
     cb()
   }
@@ -89,7 +89,7 @@ t.test('arborist-cmd', async t => {
 
   // filtering multiple workspaces by path names
   cmd.exec = function (args, cb) {
-    t.same(this.workspaces, ['a', 'c'],
+    t.same(this.workspaceNames, ['a', 'c'],
       'should set array with multiple ws names from paths')
     cb()
   }
@@ -99,7 +99,7 @@ t.test('arborist-cmd', async t => {
 
   // filtering multiple workspaces by parent path name
   cmd.exec = function (args, cb) {
-    t.same(this.workspaces, ['c', 'd'],
+    t.same(this.workspaceNames, ['c', 'd'],
       'should set array with multiple ws names from a parent folder name')
     cb()
   }