From c040ad8f30b88cb5723a821deb9ee19ade53644a Mon Sep 17 00:00:00 2001
From: merceyz <merceyz@users.noreply.github.com>
Date: Thu, 2 Sep 2021 22:22:59 +0200
Subject: [PATCH] fix: find the `pnpapi` the `issuer` belongs to

---
 lib/PnpPlugin.js           | 15 ++++++++++++++-
 lib/ResolverFactory.js     | 17 +++++++++++++++--
 lib/util/module-browser.js |  8 ++++++++
 package.json               |  4 ++--
 test/pnp.test.js           | 21 ++++++++++++++++++++-
 types.d.ts                 |  2 +-
 6 files changed, 60 insertions(+), 7 deletions(-)
 create mode 100644 lib/util/module-browser.js

diff --git a/lib/PnpPlugin.js b/lib/PnpPlugin.js
index 36f4e3d8..770afe60 100644
--- a/lib/PnpPlugin.js
+++ b/lib/PnpPlugin.js
@@ -10,7 +10,7 @@
 /** @typedef {import("./Resolver").ResolveRequest} ResolveRequest */
 /**
  * @typedef {Object} PnpApiImpl
- * @property {function(string, string, object): string} resolveToUnqualified
+ * @property {function(string, string, object): string | null} resolveToUnqualified
  */
 
 module.exports = class PnpPlugin {
@@ -55,6 +55,19 @@ module.exports = class PnpPlugin {
 					resolution = this.pnpApi.resolveToUnqualified(packageName, issuer, {
 						considerBuiltins: false
 					});
+
+					if (resolution === null) {
+						// This is either not a PnP managed issuer or it's a Node builtin
+						// Try to continue resolving with our alternatives
+						if (resolveContext.log) {
+							resolveContext.log(`issuer is not managed by the pnpapi`);
+						}
+						// FIXME: In Webpack this stops the resolution at
+						// https://github.com/webpack/enhanced-resolve/blob/029d3e2ce802ef5181355bf64f14f6d0d819ed66/lib/ConditionalPlugin.js#L52-L53
+						// instead of continuing with the alternatives
+						return callback();
+					}
+
 					if (resolveContext.fileDependencies) {
 						apiResolution = this.pnpApi.resolveToUnqualified("pnpapi", issuer, {
 							considerBuiltins: false
diff --git a/lib/ResolverFactory.js b/lib/ResolverFactory.js
index 037567bd..edca8765 100644
--- a/lib/ResolverFactory.js
+++ b/lib/ResolverFactory.js
@@ -6,6 +6,7 @@
 "use strict";
 
 const versions = require("process").versions;
+const findPnpApi = require("module").findPnpApi;
 const Resolver = require("./Resolver");
 const { getType, PathType } = require("./util/path");
 
@@ -125,8 +126,20 @@ function processPnpApiOption(option) {
 		option === undefined &&
 		/** @type {NodeJS.ProcessVersions & {pnp: string}} */ versions.pnp
 	) {
-		// @ts-ignore
-		return require("pnpapi"); // eslint-disable-line node/no-missing-require
+		const _findPnpApi = /** @type {function(string): PnpApi | null}} */ (findPnpApi);
+		if (_findPnpApi) {
+			return {
+				resolveToUnqualified(request, issuer, opts) {
+					const pnpapi = _findPnpApi(issuer);
+					if (!pnpapi) {
+						// Issuer isn't managed by PnP
+						return null;
+					}
+
+					return pnpapi.resolveToUnqualified(request, issuer, opts);
+				}
+			};
+		}
 	}
 
 	return option || null;
diff --git a/lib/util/module-browser.js b/lib/util/module-browser.js
new file mode 100644
index 00000000..1258c22e
--- /dev/null
+++ b/lib/util/module-browser.js
@@ -0,0 +1,8 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Tobias Koppers @sokra
+*/
+
+"use strict";
+
+module.exports = {};
diff --git a/package.json b/package.json
index c08417c6..c2c5a400 100644
--- a/package.json
+++ b/package.json
@@ -9,8 +9,8 @@
     "LICENSE"
   ],
   "browser": {
-    "pnpapi": false,
-    "process": "./lib/util/process-browser.js"
+    "process": "./lib/util/process-browser.js",
+    "module": "./lib/util/module-browser.js"
   },
   "dependencies": {
     "graceful-fs": "^4.2.4",
diff --git a/test/pnp.test.js b/test/pnp.test.js
index 5a989539..9aed524e 100644
--- a/test/pnp.test.js
+++ b/test/pnp.test.js
@@ -35,8 +35,11 @@ describe("pnp", () => {
 	beforeEach(() => {
 		pnpApi = /** @type {any} */ ({
 			mocks: new Map(),
+			ignoredIssuers: new Set(),
 			resolveToUnqualified(request, issuer) {
-				if (pnpApi.mocks.has(request)) {
+				if (pnpApi.ignoredIssuers.has(issuer)) {
+					return null;
+				} else if (pnpApi.mocks.has(request)) {
 					return pnpApi.mocks.get(request);
 				} else {
 					const err = /** @type {any} */ (new Error(`No way`));
@@ -250,6 +253,22 @@ describe("pnp", () => {
 			}
 		);
 	});
+	it("should fallback to alternatives when pnp doesn't manage the issuer", done => {
+		pnpApi.ignoredIssuers.add(path.resolve(__dirname, "fixtures") + "/");
+		// Add the wrong path on purpose to make sure the issuer is ignored
+		pnpApi.mocks.set("m2", path.resolve(fixture, "pkg"));
+		resolver.resolve(
+			{},
+			path.resolve(__dirname, "fixtures"),
+			"m2/a.js",
+			{},
+			(err, result) => {
+				if (err) return done(err);
+				result.should.equal(path.resolve(fixture, "../pnp-a/m2/a.js"));
+				done();
+			}
+		);
+	});
 	it("should handle the exports field when using PnP", done => {
 		pnpApi.mocks.set("m1", path.resolve(fixture, "pkg3"));
 		resolver.resolve(
diff --git a/types.d.ts b/types.d.ts
index e88d59c2..fb6b2614 100644
--- a/types.d.ts
+++ b/types.d.ts
@@ -289,7 +289,7 @@ type Plugin =
 	| { apply: (arg0: Resolver) => void }
 	| ((this: Resolver, arg1: Resolver) => void);
 declare interface PnpApiImpl {
-	resolveToUnqualified: (arg0: string, arg1: string, arg2: object) => string;
+	resolveToUnqualified: (arg0: string, arg1: string, arg2: object) => string | null;
 }
 declare interface PossibleFileSystemError {
 	code?: string;