fix(tui): attribute TermResponse to source channel #40330

Problem: Attach-time terminal probes cannot distinguish responses from
different attached UIs.

Solution: Identify the UI by RPC channel id in `TermResponse` and make
`vim.tty.request()` filter responses by channel.

runtime/doc/autocmd.txt

@@ -1227,6 +1227,7 @@ TermResponse			When Nvim receives a DA1, OSC, DCS, or APC response from
 				the host terminal. Sets |v:termresponse|.
 
 				The |event-data| has these keys (type: `vim.event.termresponse.data`):
+				- chan: the source channel id
 				- sequence: the received sequence
 
 				This is triggered even when inside an

runtime/lua/vim/_core/defaults.lua

@@ -922,7 +922,7 @@ do
   --- @param sync boolean When true (a TTY is present at startup), also send a
   --- DSR probe and synchronously wait so 'background' is set before user config,
   --- warning (E1568) if the terminal never answers the DSR.
-  local function detect_background(sync)
+  local function detect_background(sync, chan)
     -- Re-create (clear) the handler's augroup on each call so only the
     -- most-recently-attached TUI's handler remains.
     local bg_group = vim.api.nvim_create_augroup('nvim.tty.background', {})
@@ -938,36 +938,40 @@ do
     -- also reacts to runtime theme changes; the per-response bg_user_set() guard
     -- stops it once the user pins 'background'.
     local did_dsr_response = false
-    vim.tty.request(osc11 .. (sync and dsr or ''), { group = bg_group, timeout = 0 }, function(resp)
-      -- DSR response that should come after the OSC 11 response if the terminal
-      -- supports it.
-      if sync and string.match(resp, '^\027%[0n$') then
-        did_dsr_response = true
-        -- Don't stop listening: the bg response may come after the DSR response
-        -- if the terminal handles requests out of sequence. In that case, the bg
-        -- will simply be set later in the startup sequence.
-        return
-      end
+    vim.tty.request(
+      osc11 .. (sync and dsr or ''),
+      { group = bg_group, timeout = 0, chan = chan },
+      function(resp)
+        -- DSR response that should come after the OSC 11 response if the terminal
+        -- supports it.
+        if sync and string.match(resp, '^\027%[0n$') then
+          did_dsr_response = true
+          -- Don't stop listening: the bg response may come after the DSR response
+          -- if the terminal handles requests out of sequence. In that case, the bg
+          -- will simply be set later in the startup sequence.
+          return
+        end
 
-      -- Never override an explicit user value: stop once the user pins it.
-      if bg_user_set() then
-        return true
-      end
+        -- Never override an explicit user value: stop once the user pins it.
+        if bg_user_set() then
+          return true
+        end
 
-      local r, g, b = parseosc11(resp)
-      if r and g and b then
-        local rr = parsecolor(r)
-        local gg = parsecolor(g)
-        local bb = parsecolor(b)
+        local r, g, b = parseosc11(resp)
+        if r and g and b then
+          local rr = parsecolor(r)
+          local gg = parsecolor(g)
+          local bb = parsecolor(b)
 
-        if rr and gg and bb then
-          local luminance = (0.299 * rr) + (0.587 * gg) + (0.114 * bb)
-          local bg = luminance < 0.5 and 'dark' or 'light'
-          -- Use :noautocmd to suppress OptionSet event; OSC11 response may arrive after VimEnter.
-          vim.cmd('noautocmd set background=' .. bg)
+          if rr and gg and bb then
+            local luminance = (0.299 * rr) + (0.587 * gg) + (0.114 * bb)
+            local bg = luminance < 0.5 and 'dark' or 'light'
+            -- Use :noautocmd to suppress OptionSet event; OSC11 response may arrive after VimEnter.
+            vim.cmd('noautocmd set background=' .. bg)
+          end
         end
       end
-    end)
+    )
 
     if not sync then
       return
@@ -1133,7 +1137,7 @@ do
       -- runtime theme changes (mode 2031 -> TUI re-queries -> |TermResponse|);
       -- the per-response bg_user_set() guard preserves an explicit user value.
       if vim.o.ttyfast then
-        detect_background(false)
+        detect_background(false, ui.chan)
       end
     end)
   end

runtime/lua/vim/_meta/events.lua

@@ -60,4 +60,5 @@ error('Cannot require a meta file')
 --- @field cursor integer[]
 
 --- @class vim.event.termresponse.data
+--- @field chan integer
 --- @field sequence string

runtime/lua/vim/tty.lua

@@ -10,10 +10,11 @@ local M = {}
 ---
 ---@param payload string Sequence to send via nvim_ui_send(). Use empty string ('') to just register
 ---                      a listener (no sending).
----@param opts? { timeout?: integer, on_timeout?: fun(), group?: integer|string }
+---@param opts? { timeout?: integer, on_timeout?: fun(), group?: integer|string, chan?: integer }
 ---       - `timeout` (default: 1000) ms to wait before giving up, or 0 for never (caller must remove the autocmd).
 ---       - `on_timeout` optional fn called when the timeout fires.
 ---       - `group`: augroup for the TermResponse autocmd.
+---       - `chan`: only handle responses from this channel.
 ---@param on_response fun(resp:string):boolean? Called for each TermResponse. Return `true` to stop listening.
 ---@return integer # autocmd id of the TermResponse handler.
 function M.request(payload, opts, on_response)
@@ -32,7 +33,11 @@ function M.request(payload, opts, on_response)
     'TermResponse',
     opts.group,
     { nested = true },
+    ---@param ev {data: vim.event.termresponse.data}
     function(ev)
+      if opts.chan and ev.data.chan ~= opts.chan then
+        return
+      end
       local stop = on_response(ev.data.sequence)
       -- If on_response is done, cancel the timeout so on_timeout doesn't fire spuriously.
       if stop and timer and not timer:is_closing() then

src/nvim/api/events.c

@@ -66,6 +66,6 @@ void nvim_ui_term_event(uint64_t channel_id, String event, Object value, Error *
 
     const String termresponse = value.data.string;
     set_vim_var_string(VV_TERMRESPONSE, termresponse.data, (ptrdiff_t)termresponse.size);
-    do_termresponse_autocmd(termresponse);
+    do_termresponse_autocmd(termresponse, channel_id);
   }
 }

src/nvim/autocmd.c

@@ -106,6 +106,7 @@ static bool autocmd_nested = false;
 static bool autocmd_include_groups = false;
 
 static bool termresponse_changed = false;
+static uint64_t termresponse_chan_id = 0;
 
 // Map of autocmd group names and ids.
 //  name -> ID
@@ -2085,13 +2086,15 @@ BYPASS_AU:
   return retval;
 }
 
-void do_termresponse_autocmd(const String sequence)
+void do_termresponse_autocmd(const String sequence, uint64_t channel_id)
 {
-  MAXSIZE_TEMP_DICT(data, 1);
+  MAXSIZE_TEMP_DICT(data, 2);
   PUT_C(data, "sequence", STRING_OBJ(sequence));
+  PUT_C(data, "chan", INTEGER_OBJ((Integer)channel_id));
   apply_autocmds_group(EVENT_TERMRESPONSE, NULL, NULL, true, AUGROUP_ALL, NULL, NULL,
                        &DICT_OBJ(data), false);
   termresponse_changed = true;
+  termresponse_chan_id = channel_id;
 }
 
 // Block triggering autocommands until unblock_autocmd() is called.
@@ -2101,6 +2104,7 @@ void block_autocmds(void)
   // Detect if v:termresponse is set while blocked.
   if (!is_autocmd_blocked()) {
     termresponse_changed = false;
+    termresponse_chan_id = 0;
   }
   autocmd_blocked++;
 }
@@ -2115,7 +2119,7 @@ void unblock_autocmds(void)
   if (!is_autocmd_blocked() && termresponse_changed && has_event(EVENT_TERMRESPONSE)) {
     // Copied to a new allocation, as termresponse may be freed during the event.
     const String sequence = cstr_to_string(get_vim_var_str(VV_TERMRESPONSE));
-    do_termresponse_autocmd(sequence);
+    do_termresponse_autocmd(sequence, termresponse_chan_id);
     api_free_string(sequence);
   }
 }

test/functional/api/ui_spec.lua

@@ -7,6 +7,7 @@ local command = n.command
 local eq = t.eq
 local eval = n.eval
 local exec = n.exec
+local exec_lua = n.exec_lua
 local feed = n.feed
 local api = n.api
 local request = n.request
@@ -172,9 +173,10 @@ describe('nvim_ui_send', function()
   end)
 end)
 
-it('autocmds UIEnter/UILeave', function()
-  clear { args_rm = { '--headless' } }
-  exec([[
+describe('UI event channels', function()
+  it('sets chan for UIEnter/UILeave', function()
+    clear { args_rm = { '--headless' } }
+    exec([[
     let g:evs = []
     autocmd UIEnter * call add(g:evs, "UIEnter") | let g:uienter_ev = deepcopy(v:event)
     autocmd UILeave * call add(g:evs, "UILeave") | let g:uileave_ev = deepcopy(v:event)
@@ -182,62 +184,105 @@ it('autocmds UIEnter/UILeave', function()
     autocmd VimLeave * call add(g:evs, "VimLeave")
   ]])
 
-  local screen = Screen.new()
-  eq({ chan = 1 }, eval('g:uienter_ev'))
-  eq({ 'VimEnter', 'UIEnter' }, eval('g:evs'))
+    local screen = Screen.new()
+    eq({ chan = 1 }, eval('g:uienter_ev'))
+    eq({ 'VimEnter', 'UIEnter' }, eval('g:evs'))
 
-  screen:detach()
-  eq({ chan = 1 }, eval('g:uileave_ev'))
-  eq({ 'VimEnter', 'UIEnter', 'UILeave' }, eval('g:evs'))
+    screen:detach()
+    eq({ chan = 1 }, eval('g:uileave_ev'))
+    eq({ 'VimEnter', 'UIEnter', 'UILeave' }, eval('g:evs'))
 
-  local servername = api.nvim_get_vvar('servername')
+    local servername = api.nvim_get_vvar('servername')
 
-  local session2 = n.connect(servername)
-  local status2, chan2 = session2:request('nvim_get_chan_info', 0)
-  t.ok(status2)
+    local session2 = n.connect(servername)
+    local status2, chan2 = session2:request('nvim_get_chan_info', 0)
+    t.ok(status2)
 
-  local session3 = n.connect(servername)
-  local status3, chan3 = session3:request('nvim_get_chan_info', 0)
-  t.ok(status3)
+    local session3 = n.connect(servername)
+    local status3, chan3 = session3:request('nvim_get_chan_info', 0)
+    t.ok(status3)
 
-  local screen2 = Screen.new(nil, nil, nil, session2)
-  eq({ chan = chan2.id }, eval('g:uienter_ev'))
-  eq({ 'VimEnter', 'UIEnter', 'UILeave', 'UIEnter' }, eval('g:evs'))
+    local screen2 = Screen.new(nil, nil, nil, session2)
+    eq({ chan = chan2.id }, eval('g:uienter_ev'))
+    eq({ 'VimEnter', 'UIEnter', 'UILeave', 'UIEnter' }, eval('g:evs'))
 
-  screen2:detach()
-  eq({ chan = chan2.id }, eval('g:uileave_ev'))
-  eq({ 'VimEnter', 'UIEnter', 'UILeave', 'UIEnter', 'UILeave' }, eval('g:evs'))
+    screen2:detach()
+    eq({ chan = chan2.id }, eval('g:uileave_ev'))
+    eq({ 'VimEnter', 'UIEnter', 'UILeave', 'UIEnter', 'UILeave' }, eval('g:evs'))
 
-  command('let g:evs = ["…"]')
+    command('let g:evs = ["…"]')
 
-  screen2:attach(session2)
-  eq({ chan = chan2.id }, eval('g:uienter_ev'))
-  eq({ '…', 'UIEnter' }, eval('g:evs'))
+    screen2:attach(session2)
+    eq({ chan = chan2.id }, eval('g:uienter_ev'))
+    eq({ '…', 'UIEnter' }, eval('g:evs'))
 
-  Screen.new(nil, nil, nil, session3)
-  eq({ chan = chan3.id }, eval('g:uienter_ev'))
-  eq({ '…', 'UIEnter', 'UIEnter' }, eval('g:evs'))
+    Screen.new(nil, nil, nil, session3)
+    eq({ chan = chan3.id }, eval('g:uienter_ev'))
+    eq({ '…', 'UIEnter', 'UIEnter' }, eval('g:evs'))
 
-  screen:attach(n.get_session())
-  eq({ chan = 1 }, eval('g:uienter_ev'))
-  eq({ '…', 'UIEnter', 'UIEnter', 'UIEnter' }, eval('g:evs'))
+    screen:attach(n.get_session())
+    eq({ chan = 1 }, eval('g:uienter_ev'))
+    eq({ '…', 'UIEnter', 'UIEnter', 'UIEnter' }, eval('g:evs'))
 
-  session3:close()
-  t.retry(nil, 1000, function()
-    eq({}, api.nvim_get_chan_info(chan3.id))
+    session3:close()
+    t.retry(nil, 1000, function()
+      eq({}, api.nvim_get_chan_info(chan3.id))
+    end)
+    eq({ chan = chan3.id }, eval('g:uileave_ev'))
+    eq({ '…', 'UIEnter', 'UIEnter', 'UIEnter', 'UILeave' }, eval('g:evs'))
+
+    command('let g:evs = ["…"]')
+    command('autocmd UILeave * call writefile(g:evs, "Xevents.log")')
+    finally(function()
+      os.remove('Xevents.log')
+    end)
+    n.expect_exit(command, 'qall!')
+    n.check_close() -- Wait for process exit.
+    -- UILeave should have been triggered for both remaining UIs.
+    eq('…\nVimLeave\nUILeave\nUILeave\n', t.read_file('Xevents.log'))
   end)
-  eq({ chan = chan3.id }, eval('g:uileave_ev'))
-  eq({ '…', 'UIEnter', 'UIEnter', 'UIEnter', 'UILeave' }, eval('g:evs'))
 
-  command('let g:evs = ["…"]')
-  command('autocmd UILeave * call writefile(g:evs, "Xevents.log")')
-  finally(function()
-    os.remove('Xevents.log')
+  it('sets chan for TermResponse and filters tty requests', function()
+    clear()
+    local main_chan = api.nvim_get_chan_info(0).id
+    local session2 = n.connect(api.nvim_get_vvar('servername'))
+    local status2, chan2 = session2:request('nvim_get_chan_info', 0)
+    t.ok(status2)
+
+    exec_lua([[
+    _G.responses = {}
+    vim.api.nvim_create_autocmd('TermResponse', {
+      callback = function(ev)
+        table.insert(_G.responses, ev.data)
+      end,
+    })
+  ]])
+
+    request('nvim_ui_term_event', 'termresponse', 'main')
+    session2:request('nvim_ui_term_event', 'termresponse', 'other')
+
+    eq({
+      { sequence = 'main', chan = main_chan },
+      { sequence = 'other', chan = chan2.id },
+    }, exec_lua('return _G.responses'))
+
+    exec_lua(
+      [[
+      _G.filtered = {}
+      vim.tty.request('', { timeout = 0, chan = ... }, function(resp)
+        table.insert(_G.filtered, resp)
+        return true
+      end)
+    ]],
+      chan2.id
+    )
+
+    request('nvim_ui_term_event', 'termresponse', 'ignored')
+    session2:request('nvim_ui_term_event', 'termresponse', 'accepted')
+    eq({ 'accepted' }, exec_lua('return _G.filtered'))
+
+    session2:close()
   end)
-  n.expect_exit(command, 'qall!')
-  n.check_close() -- Wait for process exit.
-  -- UILeave should have been triggered for both remaining UIs.
-  eq('…\nVimLeave\nUILeave\nUILeave\n', t.read_file('Xevents.log'))
 end)
 
 it('autocmds VimSuspend/VimResume #22041', function()

test/functional/terminal/tui_spec.lua

@@ -2974,13 +2974,14 @@ describe('TUI', function()
         end,
       })
     ]])
+    local chan = child_exec_lua('return vim.api.nvim_list_uis()[1].chan')
     feed_data('\027P0$r\027\\')
     retry(nil, 4000, function()
       eq('\027P0$r', child_exec_lua('return vim.v.termresponse'))
     end)
     eq(vim.NIL, child_exec_lua('return _G.data'))
     child_exec_lua('require("ffi").C.unblock_autocmds()')
-    eq({ sequence = '\027P0$r' }, child_exec_lua('return _G.data'))
+    eq({ sequence = '\027P0$r', chan = chan }, child_exec_lua('return _G.data'))
 
     -- If TermResponse during TermResponse changes v:termresponse, data.sequence contains the actual
     -- response that triggered the autocommand.