From 07f670c23211a3b615d47877b430e1a6c0f0ac24 Mon Sep 17 00:00:00 2001
From: Joo-Byungho <kjcoco13@gmail.com>
Date: Sun, 28 Dec 2025 18:40:31 +0900
Subject: [PATCH 1/3]   fix: add HttpException handling in GraphQL error
 formatter

---
 src/common/exceptions/exception.constant.ts | 1 +
 src/common/exceptions/exception.format.ts   | 9 +++++++++
 src/common/exceptions/exception.util.ts     | 6 +++++-
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/common/exceptions/exception.constant.ts b/src/common/exceptions/exception.constant.ts
index e70f4f0..bbf84e2 100644
--- a/src/common/exceptions/exception.constant.ts
+++ b/src/common/exceptions/exception.constant.ts
@@ -10,6 +10,7 @@ export const GRAPHQL_ERROR_CODES = [
 ];
 
 export const PRESERVED_STATUS_CODES = [
+  HttpStatus.BAD_REQUEST,
   HttpStatus.UNAUTHORIZED,
   HttpStatus.FORBIDDEN,
 ] as const;
diff --git a/src/common/exceptions/exception.format.ts b/src/common/exceptions/exception.format.ts
index c29df1b..ac975a8 100644
--- a/src/common/exceptions/exception.format.ts
+++ b/src/common/exceptions/exception.format.ts
@@ -4,6 +4,7 @@ import { GraphQLError } from 'graphql';
 
 import { PRESERVED_STATUS_CODES } from './exception.constant';
 import {
+  getHttpExceptionCode,
   isBaseException,
   isGraphqlOriginalError,
   isHttpException,
@@ -26,6 +27,14 @@ const determineErrorCondition = (error: GraphQLError) => {
     };
   }
 
+  if (isHttpException(error.originalError)) {
+    const status = error.originalError.getStatus();
+    return {
+      errorStatus: status,
+      errorCode: getHttpExceptionCode(status),
+    };
+  }
+
   return {
     errorStatus: HttpStatus.INTERNAL_SERVER_ERROR,
     errorCode: 'INTERNAL_SERVER_ERROR',
diff --git a/src/common/exceptions/exception.util.ts b/src/common/exceptions/exception.util.ts
index 4938318..d7a375a 100644
--- a/src/common/exceptions/exception.util.ts
+++ b/src/common/exceptions/exception.util.ts
@@ -1,4 +1,4 @@
-import { HttpException } from '@nestjs/common';
+import { HttpException, HttpStatus } from '@nestjs/common';
 
 import { GraphQLErrorExtensions } from 'graphql';
 
@@ -23,3 +23,7 @@ export const isBaseException = (
 export const isHttpException = (error: unknown): error is HttpException => {
   return error instanceof HttpException;
 };
+
+export const getHttpExceptionCode = (status: number): string => {
+  return HttpStatus[status] || 'HTTP_ERROR';
+};

From 7a7f7b1942ca4fba13cda595f590e2fc2bff7423 Mon Sep 17 00:00:00 2001
From: Joo-Byungho <kjcoco13@gmail.com>
Date: Sun, 28 Dec 2025 18:40:45 +0900
Subject: [PATCH 2/3]   fix: extract actual validation message from
 HttpException

---
 src/common/exceptions/exception.format.ts | 11 ++++++++++-
 src/common/exceptions/exception.util.ts   | 22 ++++++++++++++++++++++
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/src/common/exceptions/exception.format.ts b/src/common/exceptions/exception.format.ts
index ac975a8..1c4c806 100644
--- a/src/common/exceptions/exception.format.ts
+++ b/src/common/exceptions/exception.format.ts
@@ -5,6 +5,7 @@ import { GraphQLError } from 'graphql';
 import { PRESERVED_STATUS_CODES } from './exception.constant';
 import {
   getHttpExceptionCode,
+  getHttpExceptionMessage,
   isBaseException,
   isGraphqlOriginalError,
   isHttpException,
@@ -84,6 +85,14 @@ const handleInternalServerError = (
   }
 };
 
+const determineErrorMessage = (error: GraphQLError): string => {
+  if (isHttpException(error.originalError)) {
+    return getHttpExceptionMessage(error.originalError);
+  }
+
+  return error.message;
+};
+
 const formatError = (
   error: GraphQLError,
   options: {
@@ -104,7 +113,7 @@ const formatError = (
   options.setHttpStatus(httpStatus);
 
   return {
-    message: error.message,
+    message: determineErrorMessage(error),
     locations: error.locations,
     path: error.path,
     extensions: {
diff --git a/src/common/exceptions/exception.util.ts b/src/common/exceptions/exception.util.ts
index d7a375a..d5a083b 100644
--- a/src/common/exceptions/exception.util.ts
+++ b/src/common/exceptions/exception.util.ts
@@ -27,3 +27,25 @@ export const isHttpException = (error: unknown): error is HttpException => {
 export const getHttpExceptionCode = (status: number): string => {
   return HttpStatus[status] || 'HTTP_ERROR';
 };
+
+export const getHttpExceptionMessage = (error: HttpException): string => {
+  const response = error.getResponse();
+
+  if (typeof response === 'string') {
+    return response;
+  }
+
+  if (typeof response === 'object' && response !== null) {
+    const { message } = response as { message?: string | string[] };
+
+    if (Array.isArray(message)) {
+      return message.join(', ');
+    }
+
+    if (typeof message === 'string') {
+      return message;
+    }
+  }
+
+  return error.message;
+};

From e7f725cad2f5061f25f657043c0590fe4e837258 Mon Sep 17 00:00:00 2001
From: Joo-Byungho <kjcoco13@gmail.com>
Date: Sun, 28 Dec 2025 18:50:21 +0900
Subject: [PATCH 3/3] fix: fallback to error code when exception message
 template is empty

---
 src/common/exceptions/exception.factory.ts | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/common/exceptions/exception.factory.ts b/src/common/exceptions/exception.factory.ts
index 65a031a..6aace89 100644
--- a/src/common/exceptions/exception.factory.ts
+++ b/src/common/exceptions/exception.factory.ts
@@ -31,9 +31,8 @@ export const createException = () => {
       constructor(arg?: ExceptionParams<K>) {
         super(statusCode, defaultMessage, code);
 
-        if (arg) {
-          this.message = composeExceptionMessage(defaultMessage, arg) as K;
-        }
+        const composed = composeExceptionMessage(defaultMessage, arg ?? {});
+        this.message = (composed || code) as K;
       }
     };
   };