From d9459f8540b66b49bd973e037b807bc86abc2960 Mon Sep 17 00:00:00 2001
From: Angus Comrie <accomrie@gmail.com>
Date: Sat, 20 Dec 2025 00:49:12 +0200
Subject: [PATCH] Fix postgres empty check when handling arrays (#25607)

### What does this PR do?
Closes #25505. This adjusts the byte length check in `DataCell:
fromBytes` to 12 bytes instead of 16, as zero-dimensional arrays will
have a shorter preamble.

### How did you verify your code works?
Test suite passes, and I've added a new test that fails in the main
branch but passes with this change. The issue only seems to crop up when
a connection is _reused_, which is curious.
---
 src/sql/postgres/DataCell.zig |  2 +-
 test/js/sql/sql.test.ts       | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/sql/postgres/DataCell.zig b/src/sql/postgres/DataCell.zig
index e020f14731..70d8196500 100644
--- a/src/sql/postgres/DataCell.zig
+++ b/src/sql/postgres/DataCell.zig
@@ -461,7 +461,7 @@ pub fn fromBytes(binary: bool, bigint: bool, oid: types.Tag, bytes: []const u8,
         // TODO: .int2_array, .float8_array
         inline .int4_array, .float4_array => |tag| {
             if (binary) {
-                if (bytes.len < 16) {
+                if (bytes.len < 12) {
                     return error.InvalidBinaryData;
                 }
                 // https://github.com/postgres/postgres/blob/master/src/backend/utils/adt/arrayfuncs.c#L1549-L1645
diff --git a/test/js/sql/sql.test.ts b/test/js/sql/sql.test.ts
index ade5843122..5067ec783c 100644
--- a/test/js/sql/sql.test.ts
+++ b/test/js/sql/sql.test.ts
@@ -12342,5 +12342,25 @@ CREATE TABLE ${table_name} (
         });
       });
     }); // Close "Misc" describe
+    test("Handles empty integer array stored as {}", async () => {
+      await using db = postgres(options);
+      const tableName = `test_${randomUUIDv7("hex").replaceAll("-", "")}`;
+
+      await db`CREATE TEMPORARY TABLE ${db(tableName)} (id SERIAL PRIMARY KEY, numbers INTEGER[])`;
+
+      // Inserting using the SQL array constructor triggers the "Failed to read data" error on SELECT.
+      await db`INSERT INTO ${db(tableName)} (numbers) VALUES (ARRAY[]::integer[])`;
+
+      // Read back - this succeeds on the first try
+      const result1 = await db`SELECT * FROM ${db(tableName)}`;
+      expect(result1).toBeArray();
+      expect(Array.from(result1[0].numbers)).toEqual([]);
+
+      // Second read to trigger connection reuse issue
+      // This is where it fails with ERR_POSTGRES_INVALID_BINARY_DATA in bun 1.3.5
+      const result2 = await db`SELECT * FROM ${db(tableName)}`;
+      expect(result2).toBeArray();
+      expect(Array.from(result2[0].numbers)).toEqual([]);
+    });
   }); // Close "PostgreSQL tests" describe
 } // Close if (isDockerEnabled())