From a4e42996e97116ab4b37c65e5f68ae3122d99664 Mon Sep 17 00:00:00 2001
From: AbhilashG12 <abhilashggg15@gmail.com>
Date: Fri, 25 Sep 2026 12:22:36 +0530
Subject: [PATCH] fix(adapter-pg): destroy pg connections after transaction
 database errors to prevent response leaking

Signed-off-by: AbhilashG12 <abhilashggg15@gmail.com>
---
 packages/adapter-pg/src/__tests__/pg.test.ts | 66 ++++++++++++++++++++
 packages/adapter-pg/src/pg.ts                |  8 ++-
 2 files changed, 72 insertions(+), 2 deletions(-)

diff --git a/packages/adapter-pg/src/__tests__/pg.test.ts b/packages/adapter-pg/src/__tests__/pg.test.ts
index 451005039372..6ad59304c44d 100644
--- a/packages/adapter-pg/src/__tests__/pg.test.ts
+++ b/packages/adapter-pg/src/__tests__/pg.test.ts
@@ -152,4 +152,70 @@ describe('PrismaPgAdapterFactory', () => {
 
     await adapter.dispose()
   })
+
+  it('should destroy connection on rollback if transaction was poisoned by a database error', async () => {
+    const config: pg.PoolConfig = { user: 'test', password: 'test', database: 'test', port: 5432, host: 'localhost' }
+    const factory = new PrismaPgAdapterFactory(config)
+    const adapter = await factory.connect()
+
+    const mockConnection = {
+      on: vi.fn(),
+      removeListener: vi.fn(),
+      query: vi.fn(),
+      release: vi.fn(),
+    }
+
+    adapter['client'].connect = vi.fn().mockResolvedValue(mockConnection)
+
+    // 1. Start Transaction (BEGIN)
+    mockConnection.query.mockResolvedValueOnce({ rows: [], rowCount: 0 })
+    const transaction = await adapter.startTransaction()
+
+    // 2. Simulate a fatal Database Error (e.g., Duplicate Key)
+    const dbError = new Error('duplicate key value violates unique constraint')
+    mockConnection.query.mockRejectedValueOnce(dbError)
+
+    await expect(transaction.executeRaw({ sql: 'INSERT INTO "User"...', args: [], argTypes: [] })).rejects.toThrow()
+
+    // 3. Rollback the transaction
+    mockConnection.query.mockResolvedValueOnce({ rows: [], rowCount: 0 }) // mock the ROLLBACK query success
+    await transaction.rollback()
+
+    // 4. VERIFY: Ensure release was called with an Error, destroying the socket
+    expect(mockConnection.release).toHaveBeenCalledWith(expect.any(Error))
+    expect(mockConnection.release.mock.calls[0][0].message).toMatch(/poisoned transaction connection/i)
+
+    await adapter.dispose()
+  })
+
+  it('should release connection normally on rollback if transaction was healthy', async () => {
+    const config: pg.PoolConfig = { user: 'test', password: 'test', database: 'test', port: 5432, host: 'localhost' }
+    const factory = new PrismaPgAdapterFactory(config)
+    const adapter = await factory.connect()
+
+    const mockConnection = {
+      on: vi.fn(),
+      removeListener: vi.fn(),
+      query: vi.fn(),
+      release: vi.fn(),
+    }
+
+    adapter['client'].connect = vi.fn().mockResolvedValue(mockConnection)
+
+    mockConnection.query.mockResolvedValueOnce({ rows: [], rowCount: 0 })
+    const transaction = await adapter.startTransaction()
+
+    // Execute a successful query
+    mockConnection.query.mockResolvedValueOnce({ rows: [], rowCount: 1 })
+    await transaction.executeRaw({ sql: 'SELECT 1', args: [], argTypes: [] })
+
+    // User triggers a manual rollback
+    mockConnection.query.mockResolvedValueOnce({ rows: [], rowCount: 0 })
+    await transaction.rollback()
+
+    // VERIFY: Ensure release was called cleanly with undefined (no error)
+    expect(mockConnection.release).toHaveBeenCalledWith(undefined)
+
+    await adapter.dispose()
+  })
 })
diff --git a/packages/adapter-pg/src/pg.ts b/packages/adapter-pg/src/pg.ts
index 6a677bdad614..c86871e1a998 100644
--- a/packages/adapter-pg/src/pg.ts
+++ b/packages/adapter-pg/src/pg.ts
@@ -31,6 +31,7 @@ type TransactionClient = pg.PoolClient
 class PgQueryable<ClientT extends StdClient | TransactionClient> implements SqlQueryable {
   readonly provider = 'postgres'
   readonly adapterName = packageName
+  protected isPoisoned = false
 
   constructor(
     protected readonly client: ClientT,
@@ -126,6 +127,7 @@ class PgQueryable<ClientT extends StdClient | TransactionClient> implements SqlQ
   }
 
   protected onError(error: unknown): never {
+    this.isPoisoned = true
     debug('Error in performIO: %O', error)
     throw new DriverAdapterError(convertDriverError(error))
   }
@@ -145,14 +147,16 @@ class PgTransaction extends PgQueryable<TransactionClient> implements Transactio
     debug(`[js::commit]`)
 
     this.cleanup?.()
-    this.client.release()
+    const err = this.isPoisoned ? new Error('Prisma: Destroying poisoned transaction connection') : undefined
+    this.client.release(err)
   }
 
   async rollback(): Promise<void> {
     debug(`[js::rollback]`)
 
     this.cleanup?.()
-    this.client.release()
+    const err = this.isPoisoned ? new Error('Prisma: Destroying poisoned transaction connection') : undefined
+    this.client.release(err)
   }
 
   async createSavepoint(name: string): Promise<void> {