From 01a9733f59ef205d113359fa778ae5521ac9cc9f Mon Sep 17 00:00:00 2001
From: JJ Liebig <jonathan.liebig@gmail.com>
Date: Mon, 14 Sep 2026 20:02:44 +0200
Subject: fix(windows): avoid lossy native Win32 input mode (#4133)

refs #3932
refs #3702
refs #3910
---
 src/client/mod.rs            |  3 ++-
 src/client/terminal_setup.rs |  6 +++---
 src/client/tests/mod.rs      | 25 +++++++++++++++++++------
 3 files changed, 24 insertions(+), 10 deletions(-)

(limited to 'src/client')

diff --git a/src/client/mod.rs b/src/client/mod.rs
index 59ff94c1..f78150ac 100644
--- a/src/client/mod.rs
+++ b/src/client/mod.rs
@@ -86,7 +86,8 @@ use terminal_setup::{
 #[cfg(test)]
 use terminal_setup::{
     should_enable_host_color_scheme_reports, windows_virtual_terminal_input_mode,
-    write_host_color_scheme_report_mode, write_terminal_restore_postlude,
+    windows_win32_input_mode_enabled, write_host_color_scheme_report_mode,
+    write_terminal_restore_postlude,
 };
 
 #[cfg(unix)]
diff --git a/src/client/terminal_setup.rs b/src/client/terminal_setup.rs
index 7441f6db..fd09a554 100644
--- a/src/client/terminal_setup.rs
+++ b/src/client/terminal_setup.rs
@@ -404,11 +404,11 @@ fn pop_keyboard_enhancement_flags() -> io::Result<()> {
     Ok(())
 }
 
-#[cfg(windows)]
-fn windows_win32_input_mode_enabled() -> bool {
+#[cfg(any(windows, test))]
+pub(super) fn windows_win32_input_mode_enabled() -> bool {
     std::env::var("HERDR_WINDOWS_INPUT_PROBE")
         .map(|probe| probe.eq_ignore_ascii_case("win32"))
-        .unwrap_or(true)
+        .unwrap_or_else(|_| is_ssh_session())
 }
 
 #[cfg(windows)]
diff --git a/src/client/tests/mod.rs b/src/client/tests/mod.rs
index 24a8135f..e3b164ae 100644
--- a/src/client/tests/mod.rs
+++ b/src/client/tests/mod.rs
@@ -102,6 +102,23 @@ fn windows_virtual_terminal_input_mode_sets_only_vti_bit() {
     assert_eq!(windows_virtual_terminal_input_mode(0x03f0), 0x03f0);
 }
 
+#[test]
+fn windows_win32_input_mode_defaults_to_ssh_and_honors_probe() {
+    let _guard = env_lock().lock().unwrap();
+    let _removed =
+        EnvVarsRemovedGuard::new(&["HERDR_WINDOWS_INPUT_PROBE", "SSH_CONNECTION", "SSH_TTY"]);
+
+    assert!(!windows_win32_input_mode_enabled());
+    {
+        let _ssh = EnvVarGuard::set("SSH_CONNECTION", "1 2 3 4");
+        assert!(windows_win32_input_mode_enabled());
+        let _probe = EnvVarGuard::set("HERDR_WINDOWS_INPUT_PROBE", "vt");
+        assert!(!windows_win32_input_mode_enabled());
+    }
+    let _probe = EnvVarGuard::set("HERDR_WINDOWS_INPUT_PROBE", "win32");
+    assert!(windows_win32_input_mode_enabled());
+}
+
 struct EnvVarsRemovedGuard {
     previous: Vec<(&'static str, Option<OsString>)>,
 }
@@ -870,12 +887,8 @@ fn terminal_control_scroll_command_maps_to_attach_scroll() {
 
 #[test]
 fn forward_clipboard_uses_local_clipboard_path() {
-    unsafe {
-        std::env::set_var("SSH_CONNECTION", "1 2 3 4");
-    }
+    let _guard = env_lock().lock().unwrap();
+    let _ssh = EnvVarGuard::set("SSH_CONNECTION", "1 2 3 4");
     assert!(forward_clipboard("dGVzdA=="));
     assert!(!forward_clipboard("not base64"));
-    unsafe {
-        std::env::remove_var("SSH_CONNECTION");
-    }
 }
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