Set --env for type = "webpack"/"rust" builds

Author: mrbbot

packages/core/src/index.ts

@@ -308,7 +308,7 @@ export class MiniflareCore<
         const configDir = path.dirname(configPath);
 
         // Add build configuration for webpack and rust builds
-        populateBuildConfig(config, configDir);
+        populateBuildConfig(config, configDir, configEnv);
 
         options = splitWranglerConfig(
           this.#plugins,

packages/core/src/plugins/build.ts

@@ -84,7 +84,8 @@ export class BuildPlugin extends Plugin<BuildOptions> implements BuildOptions {
 
 export function populateBuildConfig(
   config: WranglerConfig,
-  configDir: string
+  configDir: string,
+  configEnv?: string
 ): void {
   // If there's already a build configuration, or this isn't a "webpack"/"rust"
   // type project, leave the config as is
@@ -97,16 +98,20 @@ export function populateBuildConfig(
   config.build = { cwd: configDir, upload: { dir: "" } };
   assert(config.build.upload); // TypeScript gets annoyed if this isn't here
 
+  // Make sure to pass the correct --env to `wrangler build` so the correct
+  // webpack_config is loaded
+  const env = configEnv ? ` --env ${configEnv}` : "";
+
   if (config.type === "webpack") {
-    config.build.command = "wrangler build";
+    config.build.command = `wrangler build${env}`;
     config.build.upload.main = path.join("worker", "script.js");
   } else if (config.type === "rust") {
     // This script will be included in the root index.js bundle, but rust.mjs
     // will be in the plugins subdirectory
     const __filename = fileURLToPath(import.meta.url);
     const __dirname = path.dirname(__filename);
     const rustScript = path.join(__dirname, "plugins", "rust.js");
-    config.build.command = `wrangler build && ${process.execPath} ${rustScript}`;
+    config.build.command = `wrangler build${env} && ${process.execPath} ${rustScript}`;
     config.build.upload.main = path.join("worker", "generated", "script.js");
 
     // Add wasm binding, script.wasm will be created by rustScript

packages/core/test/fixtures/wrangler/webpack/wrangler.toml

@@ -1,3 +1,8 @@
 name = "webpack-worker"
 type = "webpack"
 compatibility_date = "2021-09-28"
+
+# This environment is only here so Wrangler doesn't complain there aren't any
+# when passing "--env dev"
+[env.dev.vars]
+KEY = "value"

packages/core/test/plugins/build.spec.ts

@@ -153,9 +153,14 @@ webpackTest(
     await rimrafPromise(path.join(webpackPath, "worker"));
     const mf = useMiniflare(
       { BuildPlugin },
-      { wranglerConfigPath: path.join(webpackPath, "wrangler.toml") }
+      {
+        wranglerConfigPath: path.join(webpackPath, "wrangler.toml"),
+        wranglerConfigEnv: "dev",
+      }
     );
-    await mf.getPlugins(); // Resolves once worker has been built
+    const plugins = await mf.getPlugins(); // Resolves once worker has been built
+    // Check correct env used
+    t.is(plugins.BuildPlugin.buildCommand, "wrangler build --env dev");
     t.true(existsSync(path.join(webpackPath, "worker", "script.js")));
 
     const res = await mf.dispatchFetch("http://localhost:8787/");