fix(generator): enhance error mapping in mapError function to provide more detailed messages for various Prisma errors

This change improves error handling by including specific error messages
from Prisma errors, making it easier to diagnose issues during database
operations.

Author: danil-iglu

packages/generator/src/generators/generateOperationCore.ts

@@ -113,27 +113,45 @@ export function mapError(error: unknown): HttpError {
     const code = (error as any).code as string
     const mapped = PRISMA_ERROR_MAP[code]
     if (mapped) {
-      return new HttpError(mapped.status, mapped.message)
+      const detail = (error as any).message
+      const message = detail
+        ? mapped.message + ': ' + detail
+        : mapped.message
+      return new HttpError(mapped.status, message)
     }
     if (typeof code === 'string' && code.startsWith('P')) {
+      const msg = (error as any).message || 'Database operation failed'
       console.warn(
         '[prisma-generator-express] Unmapped Prisma error code:',
         code,
-        (error as any).message || '',
+        msg,
       )
-      return new HttpError(500, 'Database operation failed')
+      return new HttpError(500, msg)
     }
   }
 
   if (error && typeof error === 'object' && 'name' in error) {
     const name = (error as any).name
     if (name === 'PrismaClientValidationError') {
-      return new HttpError(400, 'Invalid query parameters')
+      return new HttpError(400, (error as any).message || 'Invalid query parameters')
+    }
+    if (name === 'PrismaClientKnownRequestError') {
+      return new HttpError(400, (error as any).message || 'Database request error')
+    }
+    if (name === 'PrismaClientInitializationError') {
+      return new HttpError(503, (error as any).message || 'Database connection failed')
+    }
+    if (name === 'PrismaClientRustPanicError') {
+      return new HttpError(500, (error as any).message || 'Internal database engine error')
+    }
+    if (name === 'PrismaClientUnknownRequestError') {
+      return new HttpError(500, (error as any).message || 'Unknown database error')
     }
   }
 
+  const msg = error instanceof Error ? error.message : String(error)
   console.error('[prisma-generator-express] Unhandled error:', error)
-  return new HttpError(500, 'Internal server error')
+  return new HttpError(500, msg || 'Internal server error')
 }
 
 let _speedExtension: ((opts: any) => any) | null = null