fix: npm link should override --install-links (#5633)

Author: fritzy

lib/commands/link.js

@@ -51,6 +51,8 @@ class Link extends ArboristWorkspaceCmd {
         { code: 'ELINKGLOBAL' }
       )
     }
+    // install-links is implicitely false when running `npm link`
+    this.npm.config.set('install-links', false)
 
     // link with no args: symlink the folder to the global location
     // link with package arg: symlink the global to the local

tap-snapshots/test/lib/commands/link.js.test.cjs

@@ -48,3 +48,8 @@ exports[`test/lib/commands/link.js TAP link ws to globalDir when workspace speci
 {CWD}/test/lib/commands/tap-testdir-link-link-ws-to-globalDir-when-workspace-specified-and-no-args/global-prefix/lib/node_modules/a -> {CWD}/test/lib/commands/tap-testdir-link-link-ws-to-globalDir-when-workspace-specified-and-no-args/test-pkg-link/packages/a
 
 `
+
+exports[`test/lib/commands/link.js TAP test linked installed as symlinks > linked package should not be installed 1`] = `
+{CWD}/test/lib/commands/tap-testdir-link-test-linked-installed-as-symlinks/prefix/node_modules/mylink -> {CWD}/test/lib/commands/tap-testdir-link-test-linked-installed-as-symlinks/other/mylink
+
+`

test/lib/commands/link.js

@@ -1,9 +1,9 @@
 const t = require('tap')
-const { resolve } = require('path')
+const { resolve, join } = require('path')
 const fs = require('fs')
 
 const Arborist = require('@npmcli/arborist')
-const { fake: mockNpm } = require('../../fixtures/mock-npm')
+const { fake: mockNpm, load: fullMockNpm } = require('../../fixtures/mock-npm')
 
 const redactCwd = (path) => {
   const normalizePath = p => p
@@ -72,7 +72,6 @@ t.test('link to globalDir when in current working dir of pkg and no args', async
     path: resolve(npm.globalDir, '..'),
     global: true,
   })
-
   t.matchSnapshot(links, 'should create a global link to current pkg')
 })
 
@@ -550,3 +549,34 @@ t.test('hash character in working directory path', async t => {
 
   t.matchSnapshot(links, 'should create a global link to current pkg, even within path with hash')
 })
+
+t.test('test linked installed as symlinks', async t => {
+  // fakeMock is insufficient due to lack of flatOptions
+  const { npm } = await fullMockNpm(t, {
+    otherDirs: {
+      mylink: {
+        'package.json': JSON.stringify({
+          name: 'mylink',
+          version: '1.0.0',
+        }),
+      },
+    },
+  })
+
+  const _cwd = process.cwd()
+  process.chdir(npm.prefix)
+
+  await npm.exec('link', [
+    join('file:../other/mylink'),
+  ])
+  process.chdir(_cwd)
+  const links = await printLinks({
+    path: npm.prefix,
+  })
+
+  t.ok(fs.lstatSync(join(npm.prefix, 'node_modules', 'mylink')).isSymbolicLink(),
+    'linked path should by symbolic link'
+  )
+
+  t.matchSnapshot(links, 'linked package should not be installed')
+})