From 720aa43bd3c8f2ce018b2e9ca8f9a0b34ebcd331 Mon Sep 17 00:00:00 2001
From: Tobias Koppers <tobias.koppers@googlemail.com>
Date: Tue, 10 Aug 2021 11:23:30 +0200
Subject: [PATCH] handle hashbangs in javascript files

fixes https://github.com/vercel/next.js/issues/27806
---
 cspell.json                          |  1 +
 lib/CompatibilityPlugin.js           | 25 +++++++++++++++++++++----
 lib/NormalModule.js                  |  4 +++-
 lib/Parser.js                        |  1 +
 lib/javascript/JavascriptParser.js   |  2 ++
 test/cases/parsing/hashbang/file.js  |  2 ++
 test/cases/parsing/hashbang/file.mjs |  2 ++
 test/cases/parsing/hashbang/index.js |  9 +++++++++
 types.d.ts                           |  1 +
 9 files changed, 42 insertions(+), 5 deletions(-)
 create mode 100644 test/cases/parsing/hashbang/file.js
 create mode 100644 test/cases/parsing/hashbang/file.mjs
 create mode 100644 test/cases/parsing/hashbang/index.js

diff --git a/cspell.json b/cspell.json
index ddccec492..7aa2415b9 100644
--- a/cspell.json
+++ b/cspell.json
@@ -187,6 +187,7 @@
     "kaios",
     "parallelism",
     "gitattributes",
+    "hashbang",
 
     "webassemblyjs",
     "fsevents",
diff --git a/lib/CompatibilityPlugin.js b/lib/CompatibilityPlugin.js
index b86a64ea5..54b04bfca 100644
--- a/lib/CompatibilityPlugin.js
+++ b/lib/CompatibilityPlugin.js
@@ -69,7 +69,8 @@ class CompatibilityPlugin {
 				 * @param {JavascriptParser} parser the parser
 				 * @returns {void}
 				 */
-				const nestedWebpackRequireHandler = parser => {
+				const handler = parser => {
+					// Handle nested requires
 					parser.hooks.preStatement.tap("CompatibilityPlugin", statement => {
 						if (
 							statement.type === "FunctionDeclaration" &&
@@ -117,17 +118,33 @@ class CompatibilityPlugin {
 							parser.state.module.addPresentationalDependency(dep);
 							return true;
 						});
+
+					// Handle hashbang
+					parser.hooks.program.tap(
+						"CompatibilityPlugin",
+						(program, comments) => {
+							if (comments.length === 0) return;
+							const c = comments[0];
+							if (c.type === "Line" && c.range[0] === 0) {
+								if (parser.state.source.slice(0, 2).toString() !== "#!") return;
+								// this is a hashbang comment
+								const dep = new ConstDependency("//", 0);
+								dep.loc = c.loc;
+								parser.state.module.addPresentationalDependency(dep);
+							}
+						}
+					);
 				};
 
 				normalModuleFactory.hooks.parser
 					.for("javascript/auto")
-					.tap("CompatibilityPlugin", nestedWebpackRequireHandler);
+					.tap("CompatibilityPlugin", handler);
 				normalModuleFactory.hooks.parser
 					.for("javascript/dynamic")
-					.tap("CompatibilityPlugin", nestedWebpackRequireHandler);
+					.tap("CompatibilityPlugin", handler);
 				normalModuleFactory.hooks.parser
 					.for("javascript/esm")
-					.tap("CompatibilityPlugin", nestedWebpackRequireHandler);
+					.tap("CompatibilityPlugin", handler);
 			}
 		);
 	}
diff --git a/lib/NormalModule.js b/lib/NormalModule.js
index 598f2107c..769554a1e 100644
--- a/lib/NormalModule.js
+++ b/lib/NormalModule.js
@@ -1025,7 +1025,9 @@ class NormalModule extends Module {
 
 			let result;
 			try {
-				result = this.parser.parse(this._ast || this._source.source(), {
+				const source = this._source.source();
+				result = this.parser.parse(this._ast || source, {
+					source,
 					current: this,
 					module: this,
 					compilation: compilation,
diff --git a/lib/Parser.js b/lib/Parser.js
index f5921c229..efd673d2b 100644
--- a/lib/Parser.js
+++ b/lib/Parser.js
@@ -12,6 +12,7 @@
 
 /**
  * @typedef {Object} ParserStateBase
+ * @property {string | Buffer} source
  * @property {NormalModule} current
  * @property {NormalModule} module
  * @property {Compilation} compilation
diff --git a/lib/javascript/JavascriptParser.js b/lib/javascript/JavascriptParser.js
index 7d94e499f..f2d600c99 100644
--- a/lib/javascript/JavascriptParser.js
+++ b/lib/javascript/JavascriptParser.js
@@ -135,6 +135,8 @@ const defaultParserOptions = {
 	locations: true,
 	ecmaVersion: "latest",
 	sourceType: "module",
+	// https://github.com/tc39/proposal-hashbang
+	allowHashBang: true,
 	onComment: null
 };
 
diff --git a/test/cases/parsing/hashbang/file.js b/test/cases/parsing/hashbang/file.js
new file mode 100644
index 000000000..2866673b1
--- /dev/null
+++ b/test/cases/parsing/hashbang/file.js
@@ -0,0 +1,2 @@
+#!/usr/bin/env node
+module.exports = "ok";
diff --git a/test/cases/parsing/hashbang/file.mjs b/test/cases/parsing/hashbang/file.mjs
new file mode 100644
index 000000000..97e357ad7
--- /dev/null
+++ b/test/cases/parsing/hashbang/file.mjs
@@ -0,0 +1,2 @@
+#!/usr/bin/env node
+export default "ok";
diff --git a/test/cases/parsing/hashbang/index.js b/test/cases/parsing/hashbang/index.js
new file mode 100644
index 000000000..f4bb67453
--- /dev/null
+++ b/test/cases/parsing/hashbang/index.js
@@ -0,0 +1,9 @@
+it("should load a file with hashbang", function () {
+	var result = require("./file.js");
+	expect(result).toEqual("ok");
+});
+
+import result from "./file.mjs";
+it("should load a module with hashbang", function () {
+	expect(result).toEqual("ok");
+});
diff --git a/types.d.ts b/types.d.ts
index 754159d15..386899a2c 100644
--- a/types.d.ts
+++ b/types.d.ts
@@ -8470,6 +8470,7 @@ declare interface ParserOptionsByModuleTypeUnknown {
 }
 type ParserState = Record<string, any> & ParserStateBase;
 declare interface ParserStateBase {
+	source: string | Buffer;
 	current: NormalModule;
 	module: NormalModule;
 	compilation: Compilation;