tools: add update-npm script

I've had to update this one too many times, and much of it can be
automated, so let's do that!

The maintenance instructions have also been updated.

PR-URL: #35822
Reviewed-By: Jiawen Geng <technicalcute@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>

doc/guides/maintaining-npm.md

@@ -10,52 +10,20 @@ are at the discretion of the release and LTS teams.
 This process only covers full updates to new versions of npm. Cherry-picked
 changes can be reviewed and landed via the normal consensus seeking process.
 
-## Step 1: Clone npm
+## Step 1: Run the update script
 
 ```console
-$ git clone https://github.com/npm/cli.git npm
-$ cd npm
+$ ./tools/update-npm.sh
 ```
 
-or if you already have npm cloned make sure the repo is up to date
+## Step 2: Commit new npm
 
 ```console
-$ git remote update -p
-$ git reset --hard origin/latest
-```
-
-## Step 2: Build release
-
-```console
-$ git checkout vX.Y.Z
-$ make
-$ make release
-```
-
-Note: please run `npm dist-tag ls npm` and make sure this is the `latest`
-**dist-tag**. `latest` on git is usually released as `next` when it's time to
-downstream
-
-## Step 3: Remove old npm
-
-```console
-$ cd /path/to/node
-$ git remote update -p
-$ git checkout -b npm-x.y.z origin/master
-$ cd deps
-$ rm -rf npm
-```
-
-## Step 4: Extract and commit new npm
-
-```console
-$ tar zxf /path/to/npm/release/npm-x.y.z.tgz
-$ git add -A npm
+$ git add -A deps/npm
 $ git commit -m "deps: upgrade npm to x.y.z"
-$ cd ..
 ```
 
-## Step 5: Update licenses
+## Step 3: Update licenses
 
 ```console
 $ ./configure
@@ -68,13 +36,13 @@ $ git commit -m "doc: update npm LICENSE using license-builder.sh"
 
 Note: please ensure you are only making the updates that are changed by npm.
 
-## Step 6: Apply Whitespace fix
+## Step 4: Apply Whitespace fix
 
 ```console
 $ git rebase --whitespace=fix master
 ```
 
-## Step 7: Test the build
+## Step 5: Test the build
 
 ```console
 $ make test-npm

tools/update-npm.sh

@@ -0,0 +1,57 @@
+#!/usr/bin/env bash
+set -e
+# Shell script to update npm in the source tree to a specific version
+
+BASE_DIR="$( pwd )"/
+DEPS_DIR="$BASE_DIR"deps/
+NPM_VERSION=$1
+
+if [ "$#" -le 0 ]; then
+  echo "Error: please provide an npm version to update to"
+  exit 1
+fi
+
+WORKSPACE="$TMPDIR"update-npm-$NPM_VERSION/
+
+if [ -d "$WORKSPACE" ]; then
+  echo "Cleaning up old workspace"
+  rm -rf "$WORKSPACE"
+fi
+
+echo "Making temporary workspace"
+
+mkdir -p "$WORKSPACE"
+
+cd "$WORKSPACE"
+
+git clone git@github.com:npm/cli.git
+cd cli
+
+echo "Preparing npm release"
+
+git checkout v"$NPM_VERSION"
+make
+make release
+
+echo "Removing old npm"
+
+cd "$DEPS_DIR"
+rm -rf npm/
+
+echo "Copying new npm"
+
+tar zxf "$WORKSPACE"cli/release/npm-"$NPM_VERSION".tgz
+
+echo "Deleting temporary workspace"
+
+rm -rf "$WORKSPACE"
+
+echo ""
+echo "All done!"
+echo ""
+echo "Please git add npm, commit the new version, and whitespace-fix:"
+echo ""
+echo "$ git add -A deps/npm"
+echo "$ git commit -m \"deps: upgrade npm to $NPM_VERSION\""
+echo "$ git rebase --whitespace=fix master"
+echo ""