From 47396e78ceddc8178a81a63d0c8a7f14b814fc4c Mon Sep 17 00:00:00 2001
From: Johannes Altmanninger <aclopte@gmail.com>
Date: Fri, 3 Oct 2025 18:17:33 +0200
Subject: [PATCH] Stop requesting modifyOtherKeys on old Midnight Commander
 again

This upstream issue was fixed in 0ea77d2ec (Ticket #4597: fix CSI
parser, 2024-10-09); for old mc's we had worked around this but the
workaround was accidentally removed. Add it back for all the versions
that don't have that fix.

Fixes f0e007c4397 (Relocate tty metadata and protocols and clean
it up, 2025-06-19) Turns out this was why the "Capability" enum was
added in 2d234bb676c (Only request keyboard protocols once we know
if kitty kbd is supported, 2025-01-26).

Fixes #11869

(cherry picked from commit fcd246064b465340103da30fb694dd7c45c3e334)
---
 src/reader.rs      |  2 +-
 src/tty_handoff.rs | 21 ++++++++++++++++-----
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/src/reader.rs b/src/reader.rs
index c329df2a6..cecf03ff8 100644
--- a/src/reader.rs
+++ b/src/reader.rs
@@ -279,7 +279,7 @@ pub fn terminal_init(vars: &dyn Environment, inputfd: RawFd) -> InputEventQueue
     );
 
     let _init_tty_metadata = ScopeGuard::new((), |()| {
-        initialize_tty_protocols();
+        initialize_tty_protocols(vars);
     });
 
     if !querying_allowed(vars) {
diff --git a/src/tty_handoff.rs b/src/tty_handoff.rs
index 77ff42cdb..59fe388b8 100644
--- a/src/tty_handoff.rs
+++ b/src/tty_handoff.rs
@@ -2,6 +2,8 @@
 //! and reclaiming it after.
 
 use crate::common::{self, safe_write_loop};
+use crate::env::Environment;
+use crate::env_dispatch::MIDNIGHT_COMMANDER_SID;
 use crate::flog::{FLOG, FLOGF};
 use crate::global_safety::RelaxedAtomicBool;
 use crate::job_group::JobGroup;
@@ -60,6 +62,8 @@ pub fn xtversion() -> Option<&'static wstr> {
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
 pub enum TtyQuirks {
     None,
+    // Running Midnight Commander which can't parse CSI/OSC/DCS yet.
+    MidnightCommander,
     // Running in iTerm2 before 3.5.12, which causes issues when using the kitty keyboard protocol.
     PreKittyIterm2,
     // Whether we are running under tmux.
@@ -70,9 +74,13 @@ pub enum TtyQuirks {
 
 impl TtyQuirks {
     // Create a new TtyQuirks instance with the current environment.
-    fn detect(xtversion: &wstr) -> Self {
+    fn detect(vars: &dyn Environment, xtversion: &wstr) -> Self {
         use TtyQuirks::*;
-        if get_iterm2_version(xtversion).is_some_and(|v| v < (3, 5, 12)) {
+        if vars.get(MIDNIGHT_COMMANDER_SID).is_some()
+            && vars.get(L!("__mc_kitty_keyboard")).is_none()
+        {
+            MidnightCommander
+        } else if get_iterm2_version(xtversion).is_some_and(|v| v < (3, 5, 12)) {
             PreKittyIterm2
         } else if xtversion.starts_with(L!("tmux ")) {
             Tmux
@@ -148,7 +156,10 @@ impl TtyQuirks {
     // Determine which keyboard protocol.
     // This is used from a signal handler.
     fn safe_get_supported_protocol(&self) -> ProtocolKind {
-        use TtyQuirks::{PreKittyIterm2, Wezterm};
+        use TtyQuirks::{MidnightCommander, PreKittyIterm2, Wezterm};
+        if *self == MidnightCommander {
+            return ProtocolKind::None;
+        }
         if *self == PreKittyIterm2 {
             return ProtocolKind::Other;
         }
@@ -232,7 +243,7 @@ fn tty_protocols() -> Option<&'static TtyProtocolsSet> {
 }
 
 // Initialize serialized commands for enabling/disabling TTY protocols in signal handlers.
-pub fn initialize_tty_protocols() {
+pub fn initialize_tty_protocols(vars: &dyn Environment) {
     // Default missing query responses.
     KITTY_KEYBOARD_SUPPORTED.get_or_init(|| false);
     SCROLL_CONTENT_UP_SUPPORTED.get_or_init(|| false);
@@ -243,7 +254,7 @@ pub fn initialize_tty_protocols() {
     let mut p = TTY_PROTOCOLS.load(Acquire);
     if p.is_null() {
         // Try to swap in a new TTY protocols set.
-        p = Box::into_raw(Box::new(TtyQuirks::detect(xtversion).get_protocols()));
+        p = Box::into_raw(Box::new(TtyQuirks::detect(vars, xtversion).get_protocols()));
         if let Err(_e) = TTY_PROTOCOLS.compare_exchange(std::ptr::null_mut(), p, Release, Acquire) {
             // Safety: p comes from Box::into_raw right above,
             // and wasn't shared with any other thread.