feat(arborist): add support for dependencies script (#5094)

feat: add support for dependencies script

this is a new feature that will run the `dependencies` (as well as the `pre` and `post` versions) script any time an npm action makes a change to the installed dependency tree, whether it's adding a new dependency, removing one, or just shuffling things around to dedupe/optimize

2 files changed, 82 insertions, 1 deletions

diff --git a/workspaces/arborist/lib/arborist/reify.js b/workspaces/arborist/lib/arborist/reify.js
index 4932c17d0..faf016c70 100644
--- a/workspaces/arborist/lib/arborist/reify.js
+++ b/workspaces/arborist/lib/arborist/reify.js
@@ -22,6 +22,7 @@ const moveFile = require('@npmcli/move-file')
 const rimraf = promisify(require('rimraf'))
 const PackageJson = require('@npmcli/package-json')
 const packageContents = require('@npmcli/installed-package-contents')
+const runScript = require('@npmcli/run-script')
 const { checkEngine, checkPlatform } = require('npm-install-checks')
 const _force = Symbol.for('force')
 
@@ -1516,6 +1517,30 @@ module.exports = cls => class Reifier extends cls {
 
     if (!this[_global]) {
       await this.actualTree.meta.save()
+      const ignoreScripts = !!this.options.ignoreScripts
+      // if we aren't doing a dry run or ignoring scripts and we actually made changes to the dep
+      // tree, then run the dependencies scripts
+      if (!this[_dryRun] && !ignoreScripts && this.diff && this.diff.children.length) {
+        const { path, package: pkg } = this.actualTree.target
+        const stdio = this.options.foregroundScripts ? 'inherit' : 'pipe'
+        const { scripts = {} } = pkg
+        for (const event of ['predependencies', 'dependencies', 'postdependencies']) {
+          if (Object.prototype.hasOwnProperty.call(scripts, event)) {
+            const timer = `reify:run:${event}`
+            process.emit('time', timer)
+            log.info('run', pkg._id, event, scripts[event])
+            await runScript({
+              event,
+              path,
+              pkg,
+              stdioString: true,
+              stdio,
+              scriptShell: this.options.scriptShell,
+            })
+            process.emit('timeEnd', timer)
+          }
+        }
+      }
     }
   }
 }
diff --git a/workspaces/arborist/test/arborist/reify.js b/workspaces/arborist/test/arborist/reify.js
index a77b0fbb2..406b4281d 100644
--- a/workspaces/arborist/test/arborist/reify.js
+++ b/workspaces/arborist/test/arborist/reify.js
@@ -1,4 +1,4 @@
-const { resolve, basename } = require('path')
+const { join, resolve, basename } = require('path')
 const t = require('tap')
 const runScript = require('@npmcli/run-script')
 const localeCompare = require('@isaacs/string-locale-compare')('en')
@@ -2467,6 +2467,62 @@ t.test('add local dep with existing dev + peer/optional', async t => {
   t.equal(tree.children.size, 1, 'children')
 })
 
+t.test('runs dependencies script if tree changes', async (t) => {
+  const path = t.testdir({
+    'package.json': JSON.stringify({
+      name: 'root',
+      version: '1.0.0',
+      dependencies: {
+        abbrev: '^1.1.1',
+      },
+      scripts: {
+        predependencies: `node -e "require('fs').writeFileSync('ran-predependencies', '')"`,
+        dependencies: `node -e "require('fs').writeFileSync('ran-dependencies', '')"`,
+        postdependencies: `node -e "require('fs').writeFileSync('ran-postdependencies', '')"`,
+      },
+    }),
+  })
+
+  await reify(path)
+
+  for (const script of ['predependencies', 'dependencies', 'postdependencies']) {
+    const expectedPath = join(path, `ran-${script}`)
+    t.ok(fs.existsSync(expectedPath), `ran ${script}`)
+    // delete the files after we assert they exist
+    fs.unlinkSync(expectedPath)
+  }
+
+  // reify again without changing dependencies
+  await reify(path)
+
+  for (const script of ['predependencies', 'dependencies', 'postdependencies']) {
+    const expectedPath = join(path, `ran-${script}`)
+    // and this time we assert that they do _not_ exist
+    t.not(fs.existsSync(expectedPath), `did not run ${script}`)
+  }
+
+  // take over console.log as run-script is going to print a banner for these because
+  // they're running in the foreground
+  const _log = console.log
+  t.teardown(() => {
+    console.log = _log
+  })
+  const logs = []
+  console.log = (msg) => logs.push(msg)
+  // reify again, this time adding a new dependency
+  await reify(path, { foregroundScripts: true, add: ['once@^1.4.0'] })
+  console.log = _log
+
+  t.match(logs, [/predependencies/, /dependencies/, /postdependencies/], 'logged banners')
+
+  // files should exist again
+  for (const script of ['predependencies', 'dependencies', 'postdependencies']) {
+    const expectedPath = join(path, `ran-${script}`)
+    t.ok(fs.existsSync(expectedPath), `ran ${script}`)
+    fs.unlinkSync(expectedPath)
+  }
+})
+
 t.test('save package.json on update', t => {
   t.test('should save many deps in multiple package.json when using save=true', async t => {
     const path = fixture(t, 'workspaces-need-update')