fix(libnpmexec): install npx cache despite dryRun or packageLockOnly

lib/commands/exec.js

@@ -88,8 +88,6 @@ class Exec extends BaseCommand {
     return libexec({
       ...flatOptions,
       allowScripts: allowScriptsPolicy,
-      // we explicitly set packageLockOnly to false because if it's true when we try to install a missing package, we won't actually install it
-      packageLockOnly: false,
       // what the user asked to run args[0] is run by default
       args: [...args], // copy args so they don't get mutated
       // specify a custom command to be run instead of args[0]

test/lib/commands/exec.js

@@ -52,6 +52,42 @@ t.test('registry package', async t => {
   t.ok(exists.isFile(), 'bin ran, creating file')
 })
 
+t.test('registry package with dry-run set', async t => {
+  const registry = new MockRegistry({
+    tap: t,
+    registry: 'https://registry.npmjs.org/',
+  })
+
+  const manifest = registry.manifest({ name: '@npmcli/npx-dry-run-test' })
+  manifest.versions['1.0.0'].bin = { 'npx-dry-run-test': 'index.js' }
+
+  const { npm } = await loadMockNpm(t, {
+    config: {
+      audit: false,
+      yes: true,
+      'dry-run': true,
+    },
+    prefixDir: {
+      'npm-exec-test': {
+        'package.json': JSON.stringify(manifest),
+        'index.js': `#!/usr/bin/env node
+  require('fs').writeFileSync('npm-exec-test-success', '')`,
+      },
+    },
+  })
+
+  await registry.package({
+    times: 2,
+    manifest,
+    tarballs: {
+      '1.0.0': path.join(npm.prefix, 'npm-exec-test'),
+    } })
+
+  await npm.exec('exec', ['@npmcli/npx-dry-run-test'])
+  const exists = await fs.stat(path.join(npm.prefix, 'npm-exec-test-success'))
+  t.ok(exists.isFile(), 'package was installed and bin ran, creating file')
+})
+
 t.test('--prefix', async t => {
   const registry = new MockRegistry({
     tap: t,

workspaces/libnpmexec/lib/index.js

@@ -263,6 +263,10 @@ const exec = async (opts) => {
     await mkdir(installDir, { recursive: true })
     const npxArb = new Arborist({
       ...flatOptions,
+      // a missing package must actually be installed to the npx cache, so it can be run,
+      // even when these are set: eg, a lifecycle script inherits npm_config_dry_run from `npm publish --dry-run`
+      dryRun: false,
+      packageLockOnly: false,
       path: installDir,
     })
     const lockPath = join(installDir, 'concurrency.lock')

workspaces/libnpmexec/test/registry.js

@@ -328,3 +328,29 @@ t.test('override save to true when installing to npx cache', async t => {
     value: 'packages-2.0.0',
   })
 })
+
+t.test('install to npx cache when dryRun or packageLockOnly is set', async t => {
+  for (const flag of ['dryRun', 'packageLockOnly']) {
+    t.test(flag, async t => {
+      const { fixtures, package } = createPkg({ versions: ['2.0.0'] })
+
+      const { exec, path, registry, readOutput } = setup(t, {
+        testdir: merge(fixtures, {
+          global: {},
+        }),
+      })
+
+      await package({ registry, path })
+
+      await exec({
+        args: ['@npmcli/create-index'],
+        globalPath: resolve(path, 'global'),
+        [flag]: true,
+      })
+
+      t.match(await readOutput('@npmcli-create-index'), {
+        value: 'packages-2.0.0',
+      }, 'package was installed and its bin ran')
+    })
+  }
+})