From e1b7171bb1d22a338724fc4081100db41aff1dd8 Mon Sep 17 00:00:00 2001
From: Joshua Chen <sidachen2003@gmail.com>
Date: Mon, 2 May 2022 16:34:30 +0800
Subject: [PATCH] fix(core): allow empty static directories (#7285)

* fix(core): allow empty static directories

* improve comment

* add empty directory
---
 packages/docusaurus/src/commands/build.ts | 31 ++++++++++++++++++-----
 website/docusaurus.config.js              |  3 +++
 2 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/packages/docusaurus/src/commands/build.ts b/packages/docusaurus/src/commands/build.ts
index 69a35f758b..72d6130828 100644
--- a/packages/docusaurus/src/commands/build.ts
+++ b/packages/docusaurus/src/commands/build.ts
@@ -124,7 +124,11 @@ async function buildLocale({
     outDir,
     generatedFilesDir,
     plugins,
-    siteConfig: {baseUrl, onBrokenLinks, staticDirectories},
+    siteConfig: {
+      baseUrl,
+      onBrokenLinks,
+      staticDirectories: staticDirectoriesOption,
+    },
     routes,
   } = props;
 
@@ -162,15 +166,30 @@ async function buildLocale({
     },
   });
 
-  if (staticDirectories.length > 0) {
-    await Promise.all(staticDirectories.map((dir) => fs.ensureDir(dir)));
+  // The staticDirectories option can contain empty directories, or non-existent
+  // directories (e.g. user deleted `static`). Instead of issuing an error, we
+  // just silently filter them out, because user could have never configured it
+  // in the first place (the default option should always "work").
+  const staticDirectories = (
+    await Promise.all(
+      staticDirectoriesOption.map(async (dir) => {
+        const staticDir = path.resolve(siteDir, dir);
+        if (
+          (await fs.pathExists(staticDir)) &&
+          (await fs.readdir(staticDir)).length > 0
+        ) {
+          return staticDir;
+        }
+        return '';
+      }),
+    )
+  ).filter(Boolean);
 
+  if (staticDirectories.length > 0) {
     serverConfig = merge(serverConfig, {
       plugins: [
         new CopyWebpackPlugin({
-          patterns: staticDirectories
-            .map((dir) => path.resolve(siteDir, dir))
-            .map((dir) => ({from: dir, to: outDir})),
+          patterns: staticDirectories.map((dir) => ({from: dir, to: outDir})),
         }),
       ],
     });
diff --git a/website/docusaurus.config.js b/website/docusaurus.config.js
index 54fbf4d0af..022a36ae3c 100644
--- a/website/docusaurus.config.js
+++ b/website/docusaurus.config.js
@@ -120,6 +120,9 @@ const config = {
   staticDirectories: [
     'static',
     path.join(__dirname, '_dogfooding/_asset-tests'),
+    // Adding a non-existent static directory. If user deleted `static` without
+    // specifying `staticDirectories: []`, build should still work
+    path.join(__dirname, '_dogfooding/non-existent'),
   ],
   themes: ['live-codeblock', ...dogfoodingThemeInstances],
   plugins: [