fix bug with vitest + pages with wrangler.toml (#6911)

* infer experimentalJsonConfig from file ext

* changeset

.changeset/pretty-cherries-relate.md

@@ -0,0 +1,7 @@
+---
+"wrangler": patch
+---
+
+fix: infer experimentalJsonConfig from file extension
+
+Fixes [#5768](https://github.com/cloudflare/workers-sdk/issues/5768) - issue with vitest and Pages projects with wrangler.toml

fixtures/vitest-pool-workers-examples/pages-with-config/README.md

@@ -0,0 +1,3 @@
+# pages-with-config
+
+Tests for regression of [#5768](https://github.com/cloudflare/workers-sdk/issues/5768)

fixtures/vitest-pool-workers-examples/pages-with-config/pages-config.test.ts

@@ -0,0 +1,5 @@
+import { expect, it } from "vitest";
+
+it("should run tests even if Pages project specifies wrangler.toml", () => {
+	expect(1).toBe(1);
+});

fixtures/vitest-pool-workers-examples/pages-with-config/tsconfig.json

@@ -0,0 +1,4 @@
+{
+	"extends": "../tsconfig.node.json",
+	"include": ["./*.ts"]
+}

fixtures/vitest-pool-workers-examples/pages-with-config/vitest.config.ts

@@ -0,0 +1,11 @@
+import { defineWorkersProject } from "@cloudflare/vitest-pool-workers/config";
+
+export default defineWorkersProject({
+	test: {
+		poolOptions: {
+			workers: {
+				wrangler: { configPath: "./wrangler.toml" },
+			},
+		},
+	},
+});

fixtures/vitest-pool-workers-examples/pages-with-config/wrangler.toml

@@ -0,0 +1,6 @@
+#:schema node_modules/wrangler/config-schema.json
+name = "pages-with-config"
+compatibility_date = "2024-09-19"
+compatibility_flags = ["nodejs_compat"]
+pages_build_output_dir = "public"
+

packages/wrangler/src/api/integrations/platform/index.ts

@@ -247,8 +247,15 @@ export function unstable_getMiniflareWorkerOptions(
 	define: Record<string, string>;
 	main?: string;
 } {
+	// experimental json is usually enabled via a cli arg,
+	// so it cannot be passed to the vitest integration.
+	// instead we infer it from the config path (instead of setting a default)
+	// because wrangler.json is not compatible with pages.
+	const isJsonConfigFile =
+		configPath.endsWith(".json") || configPath.endsWith(".jsonc");
+
 	const config = readConfig(configPath, {
-		experimentalJsonConfig: true,
+		experimentalJsonConfig: isJsonConfigFile,
 		env,
 	});