test: add lib/link.js tests

- Added ELINKGLOBAL error code for when using --global
- Added tests for lib/link.js
- Do not reify, only load globals when linking a pkg to a local prefix
- Fixes: #1777

lib/link.js

@@ -1,66 +1,79 @@
-// link with no args: symlink the folder to the global location
-// link with package arg: symlink the global to the local
+'use strict'
+
+const { readdir } = require('fs')
+const { resolve } = require('path')
+
+const Arborist = require('@npmcli/arborist')
 
 const npm = require('./npm.js')
 const usageUtil = require('./utils/usage.js')
 const reifyOutput = require('./utils/reify-output.js')
-const { resolve } = require('path')
-const Arborist = require('@npmcli/arborist')
 
 const completion = (opts, cb) => {
-  const { readdir } = require('fs')
   const dir = npm.globalDir
   readdir(dir, (er, files) => cb(er, files.filter(f => !/^[._-]/.test(f))))
 }
 
 const usage = usageUtil(
   'link',
   'npm link (in package dir)' +
-  '\nnpm link [<@scope>/]<pkg>[@<version>]'
+  '\nnpm link [<@scope>/]<pkg>'
 )
 
 const cmd = (args, cb) => link(args).then(() => cb()).catch(cb)
 
 const link = async args => {
   if (npm.config.get('global')) {
-    throw new Error(
-      'link should never be --global.\n' +
-      'Please re-run this command with --local'
+    throw Object.assign(
+      new Error(
+        'link should never be --global.\n' +
+        'Please re-run this command with --local'
+      ),
+      { code: 'ELINKGLOBAL' }
     )
   }
 
+  // link with no args: symlink the folder to the global location
+  // link with package arg: symlink the global to the local
   args = args.filter(a => resolve(a) !== npm.prefix)
-  return args.length ? linkInstall(args) : linkPkg()
+  return args.length
+    ? linkInstall(args)
+    : linkPkg()
 }
 
 const linkInstall = async args => {
-  // add all the args as global installs, and then add symlink installs locally
-  // to the packages in the global space.
+  // load current packages from the global space,
+  // and then add symlinks installs locally
   const globalTop = resolve(npm.globalDir, '..')
   const globalArb = new Arborist({
     ...npm.flatOptions,
     path: globalTop,
     global: true
   })
 
-  const globals = await globalArb.reify({ add: args })
+  const globals = await globalArb.loadActual()
+
+  const links = [
+    ...globals.children.values()
+  ]
+    .filter(i => args.some(j => j === i.name))
 
-  const links = globals.edgesOut.keys()
   const localArb = new Arborist({
     ...npm.flatOptions,
     path: npm.prefix
   })
   await localArb.reify({
-    add: links.map(l => `file:${resolve(globalTop, 'node_modules', l)}`)
+    add: links.map(l => `file:${resolve(globalTop, 'node_modules', l.path)}`)
   })
 
   reifyOutput(localArb)
 }
 
 const linkPkg = async () => {
+  const globalTop = resolve(npm.globalDir, '..')
   const arb = new Arborist({
     ...npm.flatOptions,
-    path: resolve(npm.globalDir, '..'),
+    path: globalTop,
     global: true
   })
   await arb.reify({ add: [`file:${npm.prefix}`] })

tap-snapshots/test-lib-link.js-TAP.test.js

@@ -0,0 +1,19 @@
+/* IMPORTANT
+ * This snapshot file is auto-generated, but designed for humans.
+ * It should be checked into source control and tracked carefully.
+ * Re-generate by setting TAP_SNAPSHOT=1 and running tests.
+ * Make sure to inspect the output below.  Do not ignore changes!
+ */
+'use strict'
+exports[`test/lib/link.js TAP link global linked pkg to local nm when using args > should create a local symlink to global pkg 1`] = `
+{CWD}/test/lib/link-link-global-linked-pkg-to-local-nm-when-using-args/my-project/node_modules/a -> {CWD}/test/lib/link-link-global-linked-pkg-to-local-nm-when-using-args/global-prefix/lib/node_modules/a
+{CWD}/test/lib/link-link-global-linked-pkg-to-local-nm-when-using-args/my-project/node_modules/@myscope/bar -> {CWD}/test/lib/link-link-global-linked-pkg-to-local-nm-when-using-args/global-prefix/lib/node_modules/@myscope/bar
+{CWD}/test/lib/link-link-global-linked-pkg-to-local-nm-when-using-args/my-project/node_modules/test-pkg-link -> {CWD}/test/lib/link-link-global-linked-pkg-to-local-nm-when-using-args/test-pkg-link
+{CWD}/test/lib/link-link-global-linked-pkg-to-local-nm-when-using-args/my-project/node_modules/@myscope/linked -> {CWD}/test/lib/link-link-global-linked-pkg-to-local-nm-when-using-args/scoped-linked
+
+`
+
+exports[`test/lib/link.js TAP link to globalDir when in current working dir of pkg and no args > should create a global link to current pkg 1`] = `
+{CWD}/test/lib/link-link-to-globalDir-when-in-current-working-dir-of-pkg-and-no-args/global-prefix/lib/node_modules/test-pkg-link -> {CWD}/test/lib/link-link-to-globalDir-when-in-current-working-dir-of-pkg-and-no-args/test-pkg-link
+
+`

test/lib/link.js

@@ -0,0 +1,218 @@
+const { resolve } = require('path')
+
+const Arborist = require('@npmcli/arborist')
+const t = require('tap')
+const requireInject = require('require-inject')
+
+const redactCwd = (path) => {
+  const normalizePath = p => p
+    .replace(/\\+/g, '/')
+    .replace(/\r\n/g, '\n')
+  return normalizePath(path)
+    .replace(new RegExp(normalizePath(process.cwd()), 'g'), '{CWD}')
+}
+
+t.cleanSnapshot = (str) => redactCwd(str)
+
+let reifyOutput
+const npm = {
+  globalDir: null,
+  prefix: null,
+  flatOptions: {},
+  config: {
+    get () { return false }
+  }
+}
+const printLinks = async (opts) => {
+  let res = ''
+  const arb = new Arborist(opts)
+  const tree = await arb.loadActual()
+  const linkedItems = [...tree.inventory.values()]
+  for (const item of linkedItems) {
+    if (item.target)
+      res += `${item.path} -> ${item.target.path}\n`
+  }
+  return res
+}
+
+const mocks = {
+  '../../lib/npm.js': npm,
+  '../../lib/utils/reify-output.js': () => reifyOutput()
+}
+
+const link = requireInject('../../lib/link.js', mocks)
+
+t.test('link to globalDir when in current working dir of pkg and no args', (t) => {
+  t.plan(2)
+
+  const testdir = t.testdir({
+    'global-prefix': {
+      lib: {
+        node_modules: {
+          a: {
+            'package.json': JSON.stringify({
+              name: 'a',
+              version: '1.0.0'
+            })
+          }
+        }
+      }
+    },
+    'test-pkg-link': {
+      'package.json': JSON.stringify({
+        name: 'test-pkg-link',
+        version: '1.0.0'
+      })
+    }
+  })
+  npm.globalDir = resolve(testdir, 'global-prefix', 'lib', 'node_modules')
+  npm.prefix = resolve(testdir, 'test-pkg-link')
+
+  reifyOutput = async () => {
+    reifyOutput = undefined
+
+    const links = await printLinks({
+      path: resolve(npm.globalDir, '..'),
+      global: true
+    })
+
+    t.matchSnapshot(links, 'should create a global link to current pkg')
+  }
+
+  link([], (err) => {
+    t.ifError(err, 'should not error out')
+  })
+})
+
+t.test('link global linked pkg to local nm when using args', (t) => {
+  t.plan(2)
+
+  const testdir = t.testdir({
+    'global-prefix': {
+      lib: {
+        node_modules: {
+          '@myscope': {
+            foo: {
+              'package.json': JSON.stringify({
+                name: '@myscope/foo',
+                version: '1.0.0'
+              })
+            },
+            bar: {
+              'package.json': JSON.stringify({
+                name: '@myscope/bar',
+                version: '1.0.0'
+              })
+            },
+            linked: t.fixture('symlink', '../../../../scoped-linked')
+          },
+          a: {
+            'package.json': JSON.stringify({
+              name: 'a',
+              version: '1.0.0'
+            })
+          },
+          b: {
+            'package.json': JSON.stringify({
+              name: 'b',
+              version: '1.0.0'
+            })
+          },
+          'test-pkg-link': t.fixture('symlink', '../../../test-pkg-link')
+        }
+      }
+    },
+    'test-pkg-link': {
+      'package.json': JSON.stringify({
+        name: 'test-pkg-link',
+        version: '1.0.0'
+      })
+    },
+    'scoped-linked': {
+      'package.json': JSON.stringify({
+        name: '@myscope/linked',
+        version: '1.0.0'
+      })
+    },
+    'my-project': {
+      'package.json': JSON.stringify({
+        name: 'my-project',
+        version: '1.0.0',
+        dependencies: {
+          foo: '^1.0.0'
+        }
+      }),
+      node_modules: {
+        foo: {
+          'package.json': JSON.stringify({
+            name: 'foo',
+            version: '1.0.0'
+          })
+        }
+      }
+    }
+  })
+  npm.globalDir = resolve(testdir, 'global-prefix', 'lib', 'node_modules')
+  npm.prefix = resolve(testdir, 'my-project')
+
+  reifyOutput = async () => {
+    reifyOutput = undefined
+
+    const links = await printLinks({
+      path: npm.prefix
+    })
+
+    t.matchSnapshot(links, 'should create a local symlink to global pkg')
+  }
+
+  // installs examples for:
+  // - test-pkg-link: pkg linked to globalDir from local fs
+  // - @myscope/linked: scoped pkg linked to globalDir from local fs
+  // - @myscope/bar: prev installed scoped package available in globalDir
+  // - a: prev installed package available in globalDir
+  link(['test-pkg-link', '@myscope/linked', '@myscope/bar', 'a'], (err) => {
+    t.ifError(err, 'should not error out')
+  })
+})
+
+t.test('completion', (t) => {
+  const testdir = t.testdir({
+    'global-prefix': {
+      lib: {
+        node_modules: {
+          foo: {},
+          bar: {},
+          lorem: {},
+          ipsum: {}
+        }
+      }
+    }
+  })
+  npm.globalDir = resolve(testdir, 'global-prefix', 'lib', 'node_modules')
+
+  link.completion({}, (err, words) => {
+    t.ifError(err, 'should not error out')
+    t.deepEqual(
+      words,
+      ['bar', 'foo', 'ipsum', 'lorem'],
+      'should list all package names available in globalDir'
+    )
+    t.end()
+  })
+})
+
+t.test('--global option', (t) => {
+  const _config = npm.config
+  npm.config = { get () { return true } }
+  link([], (err) => {
+    npm.config = _config
+
+    t.match(
+      err.message,
+      /link should never be --global/,
+      'should throw an useful error'
+    )
+
+    t.end()
+  })
+})