Merge pull request #4307 from backstage/rugvip/devres

cli,config-loader,app-backend: fixes for module resolution and config loading

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);
+  };
+}

packages/config-loader/src/lib/schema/compile.ts

@@ -69,6 +69,14 @@ export function compileConfigSchemas(
     },
   });
 
+  for (const schema of schemas) {
+    try {
+      ajv.compile(schema.value);
+    } catch (error) {
+      throw new Error(`Schema at ${schema.path} is invalid, ${error}`);
+    }
+  }
+
   const merged = mergeAllOf(
     { allOf: schemas.map(_ => _.value) },
     {