From 03177610a8afb32f8e6e8c7de8d3bc8a011e21d0 Mon Sep 17 00:00:00 2001
From: Patrik Oldsberg <poldsberg@gmail.com>
Date: Fri, 29 Jan 2021 16:58:18 +0100
Subject: [PATCH] cli: add fix for module resolution in backend bundle config

---
 packages/cli/src/lib/bundler/config.ts | 31 +++++++++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/packages/cli/src/lib/bundler/config.ts b/packages/cli/src/lib/bundler/config.ts
index c53a8329f5..6fbcc65c9a 100644
--- a/packages/cli/src/lib/bundler/config.ts
+++ b/packages/cli/src/lib/bundler/config.ts
@@ -219,7 +219,7 @@ export async function createBackendConfig(
         }
       : {}),
     externals: [
-      nodeExternals({
+      nodeExternalsWithResolve({
         modulesDir: paths.rootNodeModules,
         additionalModuleDirs: moduleDirs,
         allowlist: ['webpack/hot/poll?100', ...localPackageNames],
@@ -296,3 +296,32 @@ export async function createBackendConfig(
     ],
   };
 }
+
+// This makes the module resolution happen from the context of each non-external module, rather
+// than the main entrypoint. This fixes a bug where dependencies would be resolved from the backend
+// package rather than each individual backend package and plugin.
+//
+// TODO(Rugvip): Feature suggestion/contribute this to webpack-externals
+function nodeExternalsWithResolve(
+  options: Parameters<typeof nodeExternals>[0],
+) {
+  let currentContext: string;
+  const externals = nodeExternals({
+    ...options,
+    importType(request) {
+      const resolved = require.resolve(request, {
+        paths: [currentContext],
+      });
+      return `commonjs ${resolved}`;
+    },
+  });
+
+  return (
+    context: string,
+    request: string,
+    callback: webpack.ExternalsFunctionCallback,
+  ) => {
+    currentContext = context;
+    return externals(context, request, callback);
+  };
+}