Fix: Zod errors missing stacktrace (#7380)

* wip: figure out stack issue, weird JSON stringify bug on zod issue

* refactor: return data instead of mutating

* refactor: remove need for reassignment

* fix: e.stack only

* chore: changeset

2 files changed, 28 insertions, 12 deletions

diff --git a/.changeset/real-dryers-leave.md b/.changeset/real-dryers-leave.md
new file mode 100644
index 000000000..4d31e082a
--- /dev/null
+++ b/.changeset/real-dryers-leave.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fix missing stacktraces for Zod errors
diff --git a/packages/astro/src/core/errors/dev/utils.ts b/packages/astro/src/core/errors/dev/utils.ts
index 28445ba32..29468c7fd 100644
--- a/packages/astro/src/core/errors/dev/utils.ts
+++ b/packages/astro/src/core/errors/dev/utils.ts
@@ -24,9 +24,13 @@ export function collectErrorMetadata(e: any, rootFolder?: URL | undefined): Erro
 			? (e.errors as SSRError[])
 			: [e as SSRError];
 
-	err.forEach((error) => {
-		if (error.stack) {
-			error = collectInfoFromStacktrace(e);
+	err.forEach((error, idx) => {
+		if (e.stack) {
+			const stackInfo = collectInfoFromStacktrace(e);
+			error.stack = stackInfo.stack;
+			error.loc = stackInfo.loc;
+			error.plugin = stackInfo.plugin;
+			error.pluginCode = stackInfo.pluginCode;
 		}
 
 		// Make sure the file location is absolute, otherwise:
@@ -141,15 +145,22 @@ See https://docs.astro.build/en/guides/troubleshooting/#document-or-window-is-no
 	return err.hint;
 }
 
-function collectInfoFromStacktrace(error: SSRError): SSRError {
-	if (!error.stack) return error;
+type StackInfo = Pick<SSRError, 'stack' | 'loc' | 'plugin' | 'pluginCode'>;
+
+function collectInfoFromStacktrace(error: SSRError & { stack: string }): StackInfo {
+	let stackInfo: StackInfo = {
+		stack: error.stack,
+		plugin: error.plugin,
+		pluginCode: error.pluginCode,
+		loc: error.loc,
+	};
 
 	// normalize error stack line-endings to \n
-	error.stack = normalizeLF(error.stack);
+	stackInfo.stack = normalizeLF(error.stack);
 	const stackText = stripAnsi(error.stack);
 
 	// Try to find possible location from stack if we don't have one
-	if (!error.loc || (!error.loc.column && !error.loc.line)) {
+	if (!stackInfo.loc || (!stackInfo.loc.column && !stackInfo.loc.line)) {
 		const possibleFilePath =
 			error.loc?.file ||
 			error.pluginCode ||
@@ -168,7 +179,7 @@ function collectInfoFromStacktrace(error: SSRError): SSRError {
 				file = fileURLToPath(file);
 			} catch {}
 
-			error.loc = {
+			stackInfo.loc = {
 				file,
 				line: Number.parseInt(line),
 				column: Number.parseInt(column),
@@ -177,17 +188,17 @@ function collectInfoFromStacktrace(error: SSRError): SSRError {
 	}
 
 	// Derive plugin from stack (if possible)
-	if (!error.plugin) {
-		error.plugin =
+	if (!stackInfo.plugin) {
+		stackInfo.plugin =
 			/withastro\/astro\/packages\/integrations\/([\w-]+)/gim.exec(stackText)?.at(1) ||
 			/(@astrojs\/[\w-]+)\/(server|client|index)/gim.exec(stackText)?.at(1) ||
 			undefined;
 	}
 
 	// Normalize stack (remove `/@fs/` urls, etc)
-	error.stack = cleanErrorStack(error.stack);
+	stackInfo.stack = cleanErrorStack(error.stack);
 
-	return error;
+	return stackInfo;
 }
 
 function cleanErrorStack(stack: string) {