From 04a4d1e02facaad1675b2811e33541627f1cd7e1 Mon Sep 17 00:00:00 2001
From: Copilot <198982749+Copilot@users.noreply.github.com>
Date: Sun, 28 Dec 2025 14:48:27 +0900
Subject: [PATCH] Prevent array.tofile re-entrant deadlock and add regression
 snippet (#6559)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: youknowone <69878+youknowone@users.noreply.github.com>
---
 crates/stdlib/src/array.rs           |  6 ++++--
 extra_tests/snippets/stdlib_array.py | 17 +++++++++++++++++
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/crates/stdlib/src/array.rs b/crates/stdlib/src/array.rs
index 49ca4a890..b51bc02d3 100644
--- a/crates/stdlib/src/array.rs
+++ b/crates/stdlib/src/array.rs
@@ -938,8 +938,10 @@ mod array {
             /* XXX Make the block size settable */
             const BLOCKSIZE: usize = 64 * 1024;
 
-            let bytes = self.read();
-            let bytes = bytes.get_bytes();
+            let bytes = {
+                let bytes = self.read();
+                bytes.get_bytes().to_vec()
+            };
 
             for b in bytes.chunks(BLOCKSIZE) {
                 let b = PyBytes::from(b.to_vec()).into_ref(&vm.ctx);
diff --git a/extra_tests/snippets/stdlib_array.py b/extra_tests/snippets/stdlib_array.py
index 34eac9491..ed2a8f223 100644
--- a/extra_tests/snippets/stdlib_array.py
+++ b/extra_tests/snippets/stdlib_array.py
@@ -126,3 +126,20 @@ assert str(i.__class__.__name__) == "arrayiterator"
 a = array("B", [0])
 assert a.__contains__(0)
 assert not a.__contains__(1)
+
+
+class _ReenteringWriter:
+    def __init__(self, arr):
+        self.arr = arr
+        self.reentered = False
+
+    def write(self, chunk):
+        if not self.reentered:
+            self.reentered = True
+            self.arr.append(0)
+        return len(chunk)
+
+
+arr = array("b", range(128))
+arr.tofile(_ReenteringWriter(arr))
+assert len(arr) == 129