From 7e8a710ca33bed6cbdcb5af697f7a16d9ed66bd5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Henrik=20B=C3=B6ving?= <hargonix@gmail.com>
Date: Thu, 16 Apr 2026 14:38:17 +0200
Subject: [PATCH] fix: two bugs in io.cpp (#13427)

This PR fixes two minor bugs in `io.cpp`:
1. A resource leak in a Windows error path of
`Std.Time.Database.Windows.getNextTransition`
2. A buffer overrun in `IO.appPath` on linux when the executable is a
symlink at max path length.
---
 src/runtime/io.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/runtime/io.cpp b/src/runtime/io.cpp
index f37250b0df..a4cac03191 100644
--- a/src/runtime/io.cpp
+++ b/src/runtime/io.cpp
@@ -752,6 +752,7 @@ extern "C" LEAN_EXPORT obj_res lean_windows_get_next_transition(b_obj_arg timezo
     u_strToUTF8(dst_name, sizeof(dst_name), &dst_name_len, tzID, tzIDLength, &status);
 
     if (U_FAILURE(status)) {
+        ucal_close(cal);
         return lean_io_result_mk_error(lean_mk_io_error_invalid_argument(EINVAL, mk_string("failed to convert DST name to UTF-8")));
     }
 
@@ -1397,7 +1398,7 @@ extern "C" LEAN_EXPORT obj_res lean_io_app_path() {
     memset(dest, 0, PATH_MAX);
     pid_t pid = getpid();
     snprintf(path, PATH_MAX, "/proc/%d/exe", pid);
-    if (readlink(path, dest, PATH_MAX) == -1) {
+    if (readlink(path, dest, PATH_MAX - 1) == -1) {
         return io_result_mk_error("failed to locate application");
     } else {
         return io_result_mk_ok(mk_string(dest));