fix: assert failure when changing 'ut' while waiting for CursorHold (#20241)

2 files changed, 17 insertions, 5 deletions

diff --git a/src/nvim/os/input.c b/src/nvim/os/input.c
index 8fc4a5dce5..fc7390a303 100644
--- a/src/nvim/os/input.c
+++ b/src/nvim/os/input.c
@@ -133,7 +133,7 @@ int os_inchar(uint8_t *buf, int maxlen, int ms, int tb_change_cnt, MultiQueue *e
     }
   } else {
     uint64_t wait_start = os_hrtime();
-    assert((int)p_ut >= cursorhold_time);
+    cursorhold_time = MIN(cursorhold_time, (int)p_ut);
     if ((result = inbuf_poll((int)p_ut - cursorhold_time, events)) == kInputNone) {
       if (read_stream.closed && silent_mode) {
         // Drained eventloop & initial input; exit silent/batch-mode (-es/-Es).
@@ -148,7 +148,6 @@ int os_inchar(uint8_t *buf, int maxlen, int ms, int tb_change_cnt, MultiQueue *e
       }
     } else {
       cursorhold_time += (int)((os_hrtime() - wait_start) / 1000000);
-      cursorhold_time = MIN(cursorhold_time, (int)p_ut);
     }
   }
 
diff --git a/test/functional/autocmd/cursorhold_spec.lua b/test/functional/autocmd/cursorhold_spec.lua
index 5d54610e1d..b04bd5233a 100644
--- a/test/functional/autocmd/cursorhold_spec.lua
+++ b/test/functional/autocmd/cursorhold_spec.lua
@@ -2,7 +2,6 @@ local helpers = require('test.functional.helpers')(after_each)
 
 local clear = helpers.clear
 local eq = helpers.eq
-local eval = helpers.eval
 local feed = helpers.feed
 local retry = helpers.retry
 local exec = helpers.source
@@ -12,13 +11,16 @@ local meths = helpers.meths
 before_each(clear)
 
 describe('CursorHold', function()
-  it('is triggered correctly #12587', function()
+  before_each(function()
     exec([[
+      let g:cursorhold = 0
       augroup test
         au CursorHold * let g:cursorhold += 1
       augroup END
     ]])
+  end)
 
+  it('is triggered correctly #12587', function()
     local function test_cursorhold(fn, early)
       local ut = 2
       -- if testing with small 'updatetime' fails, double its value and test again
@@ -47,6 +49,17 @@ describe('CursorHold', function()
     test_cursorhold(function() feed('<Ignore>') end, 0)
     test_cursorhold(function() meths.feedkeys(ignore_key, 'n', true) end, 0)
   end)
+
+  it("reducing 'updatetime' while waiting for CursorHold #20241", function()
+    meths.set_option('updatetime', 10000)
+    feed('0')  -- reset did_cursorhold
+    meths.set_var('cursorhold', 0)
+    sleep(50)
+    eq(0, meths.get_var('cursorhold'))
+    meths.set_option('updatetime', 20)
+    sleep(10)
+    eq(1, meths.get_var('cursorhold'))
+  end)
 end)
 
 describe('CursorHoldI', function()
@@ -64,7 +77,7 @@ describe('CursorHoldI', function()
     feed('ifoo')
     retry(5, nil, function()
       sleep(1)
-      eq(1, eval('g:cursorhold'))
+      eq(1, meths.get_var('cursorhold'))
     end)
   end)
 end)