normal.c: No garbage collection while handling an event in normal mode

Patch by @tarruda

Fixes #3588

1 files changed, 10 insertions, 0 deletions

diff --git a/src/nvim/normal.c b/src/nvim/normal.c
index fce3558e9f..d6bc416c91 100644
--- a/src/nvim/normal.c
+++ b/src/nvim/normal.c
@@ -7701,6 +7701,16 @@ static void nv_open(cmdarg_T *cap)
 // Handle an arbitrary event in normal mode
 static void nv_event(cmdarg_T *cap)
 {
+  // Garbage collection should have been executed before blocking for events in
+  // the `os_inchar` in `state_enter`, but we also disable it here in case the
+  // `os_inchar` branch was not executed(!queue_empty(loop.events), which could
+  // have `may_garbage_collect` set to true in `normal_check`).
+  //
+  // That is because here we may run code that calls `os_inchar`
+  // later(`f_confirm` or `get_keystroke` for example), but in these cases it is
+  // not safe to perform garbage collection because there could be unreferenced
+  // lists or dicts being used.
+  may_garbage_collect = false;
   queue_process_events(loop.events);
   cap->retval |= CA_COMMAND_BUSY;       // don't call edit() now
 }