fix(wrangler): avoid path collisions between performance and Performa…

…nce polyfills (#6025)

* fix(wrangler): avoid path collisions between performance and Performance polyfills

It turns out that ESBuild paths are case insensitive, which can result in
path collisions between polyfills for globalThis.performance and globalThis.Performance.

This change ensures that we encode all global names to lowercase and decode them appropriately.

The version of unenv used at HEAD currently doesn't suffer from this path collision,
but if not fixed the change introduced in https://github.com/unjs/unenv/pull/257/files
would result in Node.js API coverage regressions. This change prevents those regressions
from happening.

* fixup! fix(wrangler): avoid path collisions between performance and Performance polyfills

* fixup! fix(wrangler): avoid path collisions between performance and Performance polyfills

.changeset/lazy-cycles-pull.md

@@ -0,0 +1,9 @@
+---
+"wrangler": patch
+---
+
+fix: avoid path collisions between performance and Performance Node.js polyfills
+
+It turns out that ESBuild paths are case insensitive, which can result in path collisions between polyfills for `globalThis.performance` and `globalThis.Performance`, etc.
+
+This change ensures that we encode all global names to lowercase and decode them appropriately.

fixtures/nodejs-hybrid-app/src/index.ts

@@ -14,6 +14,20 @@ assert(buffer2.toJSON().data[0] === 1, "global.Buffer is broken");
 const buffer3 = globalThis.Buffer.of(1);
 assert(buffer3.toJSON().data[0] === 1, "globalThis.Buffer is broken");
 
+assert(performance !== undefined, "performance is missing");
+assert(global.performance !== undefined, "global.performance is missing");
+assert(
+	globalThis.performance !== undefined,
+	"globalThis.performance is missing"
+);
+
+assert(Performance !== undefined, "Performance is missing");
+assert(global.Performance !== undefined, "global.Performance is missing");
+assert(
+	globalThis.Performance !== undefined,
+	"globalThis.Performance is missing"
+);
+
 export default {
 	async fetch(
 		request: Request,

packages/wrangler/src/deployment-bundle/esbuild-plugins/hybrid-nodejs-compat.ts

@@ -95,7 +95,7 @@ function handleNodeJSGlobals(
 		...Object.keys(inject).map((globalName) =>
 			nodePath.resolve(
 				getBasePath(),
-				`_virtual_unenv_global_polyfill-${globalName}.js`
+				`_virtual_unenv_global_polyfill-${encodeToLowerCase(globalName)}.js`
 			)
 		),
 	];
@@ -104,7 +104,7 @@ function handleNodeJSGlobals(
 
 	build.onLoad({ filter: UNENV_GLOBALS_RE }, ({ path }) => {
 		// eslint-disable-next-line  @typescript-eslint/no-non-null-assertion
-		const globalName = path.match(UNENV_GLOBALS_RE)![1];
+		const globalName = decodeFromLowerCase(path.match(UNENV_GLOBALS_RE)![1]);
 		const globalMapping = inject[globalName];
 
 		if (typeof globalMapping === "string") {
@@ -132,11 +132,6 @@ function handleNodeJSGlobals(
 									*/ ""
 									}
 									/* @__PURE__ */ (() => {
-										${
-											/*
-										// TODO: should we try to preserve globalThis.${globalName} if it exists?
-										*/ ""
-										}
 										return globalThis.${globalName} = globalVar;
 									})();
 
@@ -172,11 +167,6 @@ function handleNodeJSGlobals(
 								*/ ""
 								}
 								/* @__PURE__ */ (() => {
-									${
-										/*
-									// TODO: should we try to preserve globalThis.${globalName} if it exists?
-									*/ ""
-									}
 									return globalThis.${globalName} = ${exportName};
 							})();
 
@@ -189,3 +179,27 @@ function handleNodeJSGlobals(
 		};
 	});
 }
+
+/**
+ * Encodes a case sensitive string to lowercase string by prefixing all uppercase letters
+ * with $ and turning them into lowercase letters.
+ *
+ * This function exists because ESBuild requires that all resolved paths are case insensitive.
+ * Without this transformation, ESBuild will clobber /foo/bar.js with /foo/Bar.js
+ *
+ * This is important to support `inject` config for `performance` and `Performance` introduced
+ * in https://github.com/unjs/unenv/pull/257
+ */
+function encodeToLowerCase(str: string): string {
+	return str.replaceAll(/[A-Z]/g, (letter) => `$${letter.toLowerCase()}`);
+}
+
+/**
+ * Decodes a string lowercased using `encodeToLowerCase` to the original strings
+ */
+function decodeFromLowerCase(str: string): string {
+	return str.replaceAll(
+		/\$([a-z])/g,
+		(match, letter) => `${letter.toUpperCase()}`
+	);
+}