From a22db4a45f908d2d9ffda6ae7112894bf8999f59 Mon Sep 17 00:00:00 2001
From: Daniele Varrazzo <daniele.varrazzo@gmail.com>
Date: Tue, 14 Oct 2025 03:41:34 +0200
Subject: [PATCH] test: add test to reveal the buffer corruption on dump error

---
 tests/test_copy.py       | 15 +++++++++++++++
 tests/test_copy_async.py | 17 +++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/tests/test_copy.py b/tests/test_copy.py
index a0cad5aae..e78636819 100644
--- a/tests/test_copy.py
+++ b/tests/test_copy.py
@@ -686,6 +686,21 @@ def test_binary_partial_row(conn):
             copy.write_row([16, [[None], None]])
 
 
+@pytest.mark.parametrize("format", pq.Format)
+def test_clean_buffer_on_error(conn, format):
+    cur = conn.cursor()
+    ensure_table(cur, "id serial primary key, num int4, obj jsonb")
+    with cur.copy(f"copy copy_in (num, obj) from stdin (format {format.name})") as copy:
+        copy.set_types(["int4", "jsonb"])
+        copy.write_row([15, {}])
+        with pytest.raises(TypeError):
+            copy.write_row([16, 1j])
+        copy.write_row([17, []])
+
+    cur.execute("select num, obj from copy_in order by id")
+    assert cur.fetchall() == [(15, {}), (17, [])]
+
+
 @pytest.mark.parametrize(
     "format, buffer",
     [(pq.Format.TEXT, "sample_text"), (pq.Format.BINARY, "sample_binary")],
diff --git a/tests/test_copy_async.py b/tests/test_copy_async.py
index 70d30dbda..1c9998b31 100644
--- a/tests/test_copy_async.py
+++ b/tests/test_copy_async.py
@@ -702,6 +702,23 @@ async def test_binary_partial_row(aconn):
             await copy.write_row([16, [[None], None]])
 
 
+@pytest.mark.parametrize("format", pq.Format)
+async def test_clean_buffer_on_error(aconn, format):
+    cur = aconn.cursor()
+    await ensure_table_async(cur, "id serial primary key, num int4, obj jsonb")
+    async with cur.copy(
+        f"copy copy_in (num, obj) from stdin (format {format.name})"
+    ) as copy:
+        copy.set_types(["int4", "jsonb"])
+        await copy.write_row([15, {}])
+        with pytest.raises(TypeError):
+            await copy.write_row([16, 1j])
+        await copy.write_row([17, []])
+
+    await cur.execute("select num, obj from copy_in order by id")
+    assert (await cur.fetchall()) == [(15, {}), (17, [])]
+
+
 @pytest.mark.parametrize(
     "format, buffer",
     [(pq.Format.TEXT, "sample_text"), (pq.Format.BINARY, "sample_binary")],
-- 
2.47.3