fix(create-cloudflare): Fix regression in C3's next template

[#7676](#7676)
switched C3 templates to default to `wrangler.json` instead
of `wrangler.toml`. Unfortunately, this unintendedly broke
the `next` template, which was still attempting to read
`wrangler.toml` specifically.

This commit fixes the regression.

Fixes #7770

.changeset/chilly-kings-retire.md

@@ -0,0 +1,9 @@
+---
+"create-cloudflare": patch
+---
+
+Fix regression in C3's `next` template
+
+[#7676](https://github.com/cloudflare/workers-sdk/pull/7676) switched C3 templates to default to `wrangler.json` instead of `wrangler.toml`. Unfortunately, this unintendedly broke the `next` template, which was still attempting to read `wrangler.toml` specifically. This commit fixes the regression.
+
+Fixes #7770

packages/create-cloudflare/templates/next/c3.ts

@@ -26,27 +26,27 @@ const generate = async (ctx: C3Context) => {
 
 	await runFrameworkGenerator(ctx, [projectName]);
 
-	const wranglerToml = readFile(join(getTemplatePath(ctx), "wrangler.toml"));
+	const wranglerConfig = readFile(join(getTemplatePath(ctx), "wrangler.json"));
 
 	// Note: here we add `# KV Example:` to the toml file for the KV example, we don't actually
-	//       include the comment in the template wrangler.toml file just so to keep it identical
+	//       include the comment in the template wrangler.json file just so to keep it identical
 	//       and consistent with that of all the other frameworks
 	//       (instead of making it a special case which needs extra care)
-	const newTomlContent = wranglerToml.replace(
+	const newWranglerConfigContent = wranglerConfig.replace(
 		/#\s+\[\[kv_namespaces\]\]\n#\s+binding\s+=\s+"MY_KV_NAMESPACE"\n#\s+id\s+=\s+"[a-zA-Z0-9]+?"/,
 		($1) => `# KV Example:\n${$1}`,
 	);
 
-	if (!/# KV Example/.test(newTomlContent)) {
+	if (!/# KV Example/.test(newWranglerConfigContent)) {
 		// This should never happen to users, it is a check mostly so that
-		// if the toml file is changed in a way that breaks the "KV Example" addition
+		// if the config file is changed in a way that breaks the "KV Example" addition
 		// the C3 Next.js e2e runs will fail with this
-		throw new Error("Failed to properly generate the wrangler.toml file");
+		throw new Error("Failed to properly generate the wrangler.json file");
 	}
 
-	writeFile(join(ctx.project.path, "wrangler.toml"), newTomlContent);
+	writeFile(join(ctx.project.path, "wrangler.json"), newWranglerConfigContent);
 
-	updateStatus("Created wrangler.toml file");
+	updateStatus("Created wrangler.json file");
 };
 
 const updateNextConfig = (usesTs: boolean) => {