From bc0b6c514a0838921c3985c4a744f4fde6b14846 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Oskar=20Segersv=C3=A4rd?= <victorystick@gmail.com>
Date: Thu, 12 Nov 2015 12:07:49 +0100
Subject: [PATCH] Add error message when reexporting missing identifier

---
 src/Module.js                                   | 12 +++++++++++-
 test/function/reexport-missing-error/_config.js |  8 ++++++++
 test/function/reexport-missing-error/empty.js   |  1 +
 test/function/reexport-missing-error/main.js    |  1 +
 4 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 test/function/reexport-missing-error/_config.js
 create mode 100644 test/function/reexport-missing-error/empty.js
 create mode 100644 test/function/reexport-missing-error/main.js

diff --git a/src/Module.js b/src/Module.js
index 42eaa7a..cee48de 100644
--- a/src/Module.js
+++ b/src/Module.js
@@ -194,6 +194,7 @@ export default class Module {
 			else {
 				node.specifiers.forEach( specifier => {
 					this.reexports[ specifier.exported.name ] = {
+						start: specifier.start,
 						source,
 						localName: specifier.local.name,
 						module: null // filled in later
@@ -724,7 +725,16 @@ export default class Module {
 		// export { foo } from './other.js'
 		const reexportDeclaration = this.reexports[ name ];
 		if ( reexportDeclaration ) {
-			return reexportDeclaration.module.traceExport( reexportDeclaration.localName );
+			const declaration = reexportDeclaration.module.traceExport( reexportDeclaration.localName );
+
+			if ( !declaration ) {
+				const err = new Error( `'${reexportDeclaration.localName}' is not exported by '${reexportDeclaration.module.id}' (imported by '${this.id}')` );
+				err.file = this.id;
+				err.loc = getLocation( this.code, reexportDeclaration.start );
+				throw err;
+			}
+
+			return declaration;
 		}
 
 		const exportDeclaration = this.exports[ name ];
diff --git a/test/function/reexport-missing-error/_config.js b/test/function/reexport-missing-error/_config.js
new file mode 100644
index 0000000..6918683
--- /dev/null
+++ b/test/function/reexport-missing-error/_config.js
@@ -0,0 +1,8 @@
+var assert = require( 'assert' );
+
+module.exports = {
+	description: 'reexporting a missing identifier should print an error',
+	error: function ( error ) {
+		assert.ok( /^'foo' is not exported/.test( error.message ) );
+	}
+};
diff --git a/test/function/reexport-missing-error/empty.js b/test/function/reexport-missing-error/empty.js
new file mode 100644
index 0000000..8d5a2a2
--- /dev/null
+++ b/test/function/reexport-missing-error/empty.js
@@ -0,0 +1 @@
+// this space left intentionally blank
diff --git a/test/function/reexport-missing-error/main.js b/test/function/reexport-missing-error/main.js
new file mode 100644
index 0000000..2440c7f
--- /dev/null
+++ b/test/function/reexport-missing-error/main.js
@@ -0,0 +1 @@
+export { foo as bar } from './empty.js';