Merge 'serverless: Add DatabasError type' from Pekka Enberg

Add an explicit error type so application can actually do error
handling...

Reviewed-by: Jussi Saurio <jussi.saurio@gmail.com>

Closes #2256

packages/turso-serverless/src/compat.ts

@@ -1,4 +1,5 @@
 import { Connection, connect, type Config as TursoConfig } from './connection.js';
+import { DatabaseError } from './error.js';
 
 /**
  * Configuration options for creating a libSQL-compatible client.

packages/turso-serverless/src/error.ts

@@ -0,0 +1,7 @@
+export class DatabaseError extends Error {
+  constructor(message: string) {
+    super(message);
+    this.name = 'DatabaseError';
+    Object.setPrototypeOf(this, DatabaseError.prototype);
+  }
+}

packages/turso-serverless/src/index.ts

@@ -1,3 +1,4 @@
 // Turso serverless driver entry point
 export { Connection, connect, type Config } from './connection.js';
-export { Statement } from './statement.js';
+export { Statement } from './statement.js';
+export { DatabaseError } from './error.js';

packages/turso-serverless/src/protocol.ts

@@ -1,3 +1,5 @@
+import { DatabaseError } from './error';
+
 export interface Value {
   type: 'null' | 'integer' | 'float' | 'text' | 'blob';
   value?: string | number;
@@ -165,12 +167,12 @@ export async function executeCursor(
     } catch {
       // If we can't parse the error body, use the default HTTP error message
     }
-    throw new Error(errorMessage);
+    throw new DatabaseError(errorMessage);
   }
 
   const reader = response.body?.getReader();
   if (!reader) {
-    throw new Error('No response body');
+    throw new DatabaseError('No response body');
   }
 
   const decoder = new TextDecoder();
@@ -238,7 +240,7 @@ export async function executePipeline(
   });
 
   if (!response.ok) {
-    throw new Error(`HTTP error! status: ${response.status}`);
+    throw new DatabaseError(`HTTP error! status: ${response.status}`);
   }
 
   return response.json();

packages/turso-serverless/src/session.ts

@@ -6,6 +6,7 @@ import {
   type CursorResponse,
   type CursorEntry
 } from './protocol.js';
+import { DatabaseError } from './error.js';
 
 /**
  * Configuration options for a session.
@@ -123,7 +124,7 @@ export class Session {
           break;
         case 'step_error':
         case 'error':
-          throw new Error(entry.error?.message || 'SQL execution failed');
+          throw new DatabaseError(entry.error?.message || 'SQL execution failed');
       }
     }
 
@@ -204,7 +205,7 @@ export class Session {
           break;
         case 'step_error':
         case 'error':
-          throw new Error(entry.error?.message || 'Batch execution failed');
+          throw new DatabaseError(entry.error?.message || 'Batch execution failed');
       }
     }
 

packages/turso-serverless/src/statement.ts

@@ -3,6 +3,7 @@ import {
   type CursorEntry
 } from './protocol.js';
 import { Session, type SessionConfig } from './session.js';
+import { DatabaseError } from './error.js';
 
 /**
  * A prepared SQL statement that can be executed in multiple ways.
@@ -117,7 +118,7 @@ export class Statement {
           break;
         case 'step_error':
         case 'error':
-          throw new Error(entry.error?.message || 'SQL execution failed');
+          throw new DatabaseError(entry.error?.message || 'SQL execution failed');
       }
     }
   }