fix: apply process.env override in ESM run mode, detect already-transformed CJS entries

Author: NathanFlurry

packages/nodejs/src/execution-driver.ts

@@ -1048,8 +1048,12 @@ export class NodeExecutionDriver implements RuntimeDriver {
 		// large dependency trees (e.g., PI has hundreds of @sinclair/typebox
 		// sub-modules). CJS mode uses the in-process require-setup transform
 		// which is orders of magnitude faster.
-		const sessionMode = options.mode === "run" || entryIsEsm ? "run" : "exec";
-		const userCode = entryIsEsm
+		// If the code was already CJS-transformed by _resolveEntry (has the
+		// require-esm marker), use exec mode so require() and __dirname work.
+		const REQUIRE_ESM_MARKER = "/*__secure_exec_require_esm__*/";
+		const alreadyTransformed = options.code.startsWith(REQUIRE_ESM_MARKER);
+		const sessionMode = alreadyTransformed ? "exec" : (options.mode === "run" || entryIsEsm ? "run" : "exec");
+		const userCode = entryIsEsm && !alreadyTransformed
 			? options.code
 			: (() => {
 					const transformed = transformSourceForRequireSync(
@@ -1285,6 +1289,7 @@ export class NodeExecutionDriver implements RuntimeDriver {
 			this._currentSession = session;
 
 			// Execute in V8 session
+			console.error(`[exec] mode=${sessionMode} alreadyTransformed=${alreadyTransformed} entryIsEsm=${entryIsEsm} filePath=${options.filePath} codeLen=${userCode.length}`);
 			const result = await session.execute({
 				bridgeCode,
 				postRestoreScript,
@@ -1537,7 +1542,19 @@ function buildPostRestoreScript(
 		parts.push(getIsolateRuntimeSource("applyTimingMitigationOff"));
 	}
 
-	// Apply execution overrides (env, cwd, stdin) for exec mode
+	// Apply env, cwd, and stdin overrides for all modes.
+	// These must run even in "run" (ESM) mode so that process.env and
+	// process.cwd() reflect the spawn-time configuration.
+	if (processConfig.env) {
+		parts.push(`globalThis.__runtimeProcessEnvOverride = ${JSON.stringify(processConfig.env)};`);
+		parts.push(getIsolateRuntimeSource("overrideProcessEnv"));
+	}
+	if (processConfig.cwd) {
+		parts.push(`globalThis.__runtimeProcessCwdOverride = ${JSON.stringify(processConfig.cwd)};`);
+		parts.push(getIsolateRuntimeSource("overrideProcessCwd"));
+	}
+
+	// CJS file globals (__filename, __dirname, module) only for exec mode.
 	if (mode === "exec") {
 		const commonJsFileConfig = (() => {
 			if (filePath) {
@@ -1554,14 +1571,6 @@ function buildPostRestoreScript(
 			}
 			return null;
 		})();
-		if (processConfig.env) {
-			parts.push(`globalThis.__runtimeProcessEnvOverride = ${JSON.stringify(processConfig.env)};`);
-			parts.push(getIsolateRuntimeSource("overrideProcessEnv"));
-		}
-		if (processConfig.cwd) {
-			parts.push(`globalThis.__runtimeProcessCwdOverride = ${JSON.stringify(processConfig.cwd)};`);
-			parts.push(getIsolateRuntimeSource("overrideProcessCwd"));
-		}
 		if (bridgeConfig.stdin !== undefined) {
 			parts.push(`globalThis.__runtimeStdinData = ${JSON.stringify(bridgeConfig.stdin)};`);
 			parts.push(getIsolateRuntimeSource("setStdinData"));