From 3621af9b970c80d2a6ff36569d7495391599c334 Mon Sep 17 00:00:00 2001
From: zeertzjq <zeertzjq@outlook.com>
Date: Sat, 3 Jan 2026 17:55:07 +0800
Subject: [PATCH] fix(terminal): inconsistent mode change when switching buffer
 (#37215)

Problem:  When switching to another terminal buffer in Terminal mode,
          usually Nvim stays in Terminal mode, but leaves Terminal mode
          if the old terminal buffer was deleted.
Solution: Don't always leave Terminal mode when active terminal buffer
          is deleted. Instead let terminal_check_focus() decide that.
---
 src/nvim/terminal.c                           | 10 +++++--
 test/functional/terminal/ex_terminal_spec.lua | 30 ++++++++++++++++++-
 2 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/src/nvim/terminal.c b/src/nvim/terminal.c
index ebacc3224c..3ccd2bfa7d 100644
--- a/src/nvim/terminal.c
+++ b/src/nvim/terminal.c
@@ -876,6 +876,11 @@ static bool terminal_check_focus(TerminalState *const s)
   if (s->term != curbuf->terminal) {
     // Active terminal buffer changed, flush terminal's cursor state to the UI.
     terminal_focus(s->term, false);
+    if (s->close) {
+      s->term->destroy = true;
+      s->term->opts.close_cb(s->term->opts.data);
+      s->close = false;
+    }
 
     s->term = curbuf->terminal;
     s->term->pending.cursor = true;
@@ -894,6 +899,9 @@ static int terminal_check(VimState *state)
 {
   TerminalState *const s = (TerminalState *)state;
 
+  // Shouldn't reach here when pressing a key to close the terminal buffer.
+  assert(!s->close || (s->term->buf_handle == 0 && s->term != curbuf->terminal));
+
   if (stop_insert_mode || !terminal_check_focus(s)) {
     return 0;
   }
@@ -913,7 +921,6 @@ static int terminal_check(VimState *state)
   s->term->refcount--;
   if (s->term->buf_handle == 0) {
     s->close = true;
-    return 0;
   }
 
   // Autocommands above may have changed focus, scrolled, or moved the cursor.
@@ -986,7 +993,6 @@ static int terminal_execute(VimState *state, int key)
     s->term->refcount--;
     if (s->term->buf_handle == 0) {
       s->close = true;
-      return 0;
     }
     break;
 
diff --git a/test/functional/terminal/ex_terminal_spec.lua b/test/functional/terminal/ex_terminal_spec.lua
index bd63dbe2c1..587b96bcd8 100644
--- a/test/functional/terminal/ex_terminal_spec.lua
+++ b/test/functional/terminal/ex_terminal_spec.lua
@@ -4,11 +4,12 @@ local Screen = require('test.functional.ui.screen')
 
 local assert_alive = n.assert_alive
 local clear, poke_eventloop = n.clear, n.poke_eventloop
-local testprg, source, eq = n.testprg, n.source, t.eq
+local testprg, source, eq, neq = n.testprg, n.source, t.eq, t.neq
 local feed = n.feed
 local feed_command, eval = n.feed_command, n.eval
 local fn = n.fn
 local api = n.api
+local exec_lua = n.exec_lua
 local retry = t.retry
 local ok = t.ok
 local command = n.command
@@ -156,6 +157,33 @@ describe(':terminal', function()
     feed('<Ignore>') -- Add input to separate two RPC requests
     eq({ blocking = false, mode = 'nt' }, api.nvim_get_mode())
   end)
+
+  it('switching to another terminal buffer in Terminal mode', function()
+    command('terminal')
+    local buf0 = api.nvim_get_current_buf()
+    command('terminal')
+    local buf1 = api.nvim_get_current_buf()
+    command('terminal')
+    local buf2 = api.nvim_get_current_buf()
+    neq(buf0, buf1)
+    neq(buf0, buf2)
+    neq(buf1, buf2)
+    feed('i')
+    eq({ blocking = false, mode = 't' }, api.nvim_get_mode())
+    api.nvim_set_current_buf(buf1)
+    eq({ blocking = false, mode = 't' }, api.nvim_get_mode())
+    api.nvim_set_current_buf(buf0)
+    eq({ blocking = false, mode = 't' }, api.nvim_get_mode())
+    exec_lua(function()
+      vim.api.nvim_set_current_buf(buf1)
+      vim.api.nvim_buf_delete(buf0, { force = true })
+    end)
+    eq({ blocking = false, mode = 't' }, api.nvim_get_mode())
+    api.nvim_set_current_buf(buf2)
+    eq({ blocking = false, mode = 't' }, api.nvim_get_mode())
+    api.nvim_set_current_buf(buf1)
+    eq({ blocking = false, mode = 't' }, api.nvim_get_mode())
+  end)
 end)
 
 local function test_terminal_with_fake_shell(backslash)