fix(input): allow Ctrl-C to interrupt a recursive mapping even if mapped (#18885)

test/functional/editor/ctrl_c_spec.lua

@@ -0,0 +1,94 @@
+local helpers = require('test.functional.helpers')(after_each)
+local Screen = require('test.functional.ui.screen')
+local clear, feed, source = helpers.clear, helpers.feed, helpers.source
+local command = helpers.command
+local sleep = helpers.sleep
+
+describe("CTRL-C (mapped)", function()
+  local screen
+
+  before_each(function()
+    clear()
+    screen = Screen.new(52, 6)
+    screen:attach()
+  end)
+
+  it("interrupts :global", function()
+    -- Crashes luajit.
+    if helpers.skip_fragile(pending) then
+      return
+    end
+
+    source([[
+      set nomore nohlsearch undolevels=-1
+      nnoremap <C-C> <NOP>
+    ]])
+
+    command("silent edit! test/functional/fixtures/bigfile.txt")
+
+    screen:expect([[
+      ^0000;<control>;Cc;0;BN;;;;;N;NULL;;;;               |
+      0001;<control>;Cc;0;BN;;;;;N;START OF HEADING;;;;   |
+      0002;<control>;Cc;0;BN;;;;;N;START OF TEXT;;;;      |
+      0003;<control>;Cc;0;BN;;;;;N;END OF TEXT;;;;        |
+      0004;<control>;Cc;0;BN;;;;;N;END OF TRANSMISSION;;;;|
+                                                          |
+    ]])
+
+    local function test_ctrl_c(ms)
+      feed(":global/^/p<CR>")
+      screen:sleep(ms)
+      feed("<C-C>")
+      screen:expect{any="Interrupt"}
+    end
+
+    -- The test is time-sensitive. Try different sleep values.
+    local ms_values = {100, 1000, 10000}
+    for i, ms in ipairs(ms_values) do
+      if i < #ms_values then
+        local status, _ = pcall(test_ctrl_c, ms)
+        if status then break end
+      else  -- Call the last attempt directly.
+        test_ctrl_c(ms)
+      end
+    end
+  end)
+
+  it('interrupts :sleep', function()
+    command('nnoremap <C-C> <Nop>')
+    feed(':sleep 100<CR>')
+    -- wait for :sleep to start
+    sleep(10)
+    feed('foo<C-C>')
+    -- wait for input buffer to be flushed
+    sleep(10)
+    feed('i')
+    screen:expect([[
+      ^                                                    |
+      ~                                                   |
+      ~                                                   |
+      ~                                                   |
+      ~                                                   |
+      -- INSERT --                                        |
+    ]])
+  end)
+
+  it('interrupts recursive mapping', function()
+    command('nnoremap <C-C> <Nop>')
+    command('nmap <F2> <Ignore><F2>')
+    feed('<F2>')
+    sleep(10)
+    feed('foo<C-C>')
+    -- wait for input buffer to be flushed
+    sleep(10)
+    feed('i')
+    screen:expect([[
+      ^                                                    |
+      ~                                                   |
+      ~                                                   |
+      ~                                                   |
+      ~                                                   |
+      -- INSERT --                                        |
+    ]])
+  end)
+end)