Packages: Ensure only changed packages get published for WP releases (#…

…55334)

* Packages: Ensure only changed packages get published for WP releases

* Clarify the reason for using fetch depth

* Iprove the wording for comments

.github/workflows/publish-npm-packages.yml

@@ -53,6 +53,9 @@ jobs:
               with:
                   path: publish
                   ref: wp/${{ github.event.inputs.wp_version }}
+                  # We need to ensure that Lerna can read the commit created during the previous npm publishing.
+                  # Lerna assumes that all packages need publishing if it can't access the necessary information.
+                  fetch-depth: 999
                   token: ${{ secrets.GUTENBERG_TOKEN }}
                   show-progress: ${{ runner.debug == '1' && 'true' || 'false' }}
 

bin/plugin/commands/packages.js

@@ -83,24 +83,14 @@ async function checkoutNpmReleaseBranch( {
 	/*
 	 * Create the release branch.
 	 *
-	 * Note that we are grabbing an arbitrary depth of commits
-	 * during the fetch. When `lerna` attempts to determine if
-	 * a package needs an update, it looks at `git` history,
-	 * and if we have pruned that history it will pre-emptively
-	 * publish when it doesn't need to.
-	 *
-	 * We could set a different arbitrary depth if this isn't
-	 * long enough or if it's excessive. We could also try and
-	 * find a way to more specifically fetch what we expect to
-	 * change. For example, if we knew we'll be performing
-	 * updates every two weeks, we might be conservative and
-	 * use `--shallow-since=4.weeks.ago`.
-	 *
-	 * At the time of writing, a depth of 100 pulls in all
-	 * `trunk` commits from within the past week.
+	 * Note that we are grabbing an arbitrary depth of commits (999) during the fetch.
+	 * When Lerna attempts to determine if a package needs an update, it looks at
+	 * `git` history to find the commit created during the previous npm publishing.
+	 * Lerna assumes that all packages need publishing if it can't access
+	 * the necessary information.
 	 */
 	await SimpleGit( gitWorkingDirectoryPath )
-		.fetch( 'origin', npmReleaseBranch, [ '--depth=100' ] )
+		.fetch( 'origin', npmReleaseBranch, [ '--depth=999' ] )
 		.checkout( npmReleaseBranch );
 	log(
 		'>> The local npm release branch ' +