vim-patch:9.0.2050: Vim9: crash with deferred function call and exception (#25715)

Problem:  Vim9: crash with deferred function call and exception
Solution: Save and restore exception state

Crash when a deferred function is called after an exception and another
exception is thrown

closes: vim/vim#13376
closes: vim/vim#13377

https://github.com/vim/vim/commit/c59c1e0d88651a71ece7366e418f1253abbe2a28

The change in check_due_timer() is N/A as Nvim calls timer callbacks on
the main loop.

Co-authored-by: Yegappan Lakshmanan <yegappan@yahoo.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/src/nvim/ex_eval.c b/src/nvim/ex_eval.c
index c656f785c9..7412757726 100644
--- a/src/nvim/ex_eval.c
+++ b/src/nvim/ex_eval.c
@@ -661,6 +661,35 @@ static void finish_exception(except_T *excp)
   discard_exception(excp, true);
 }
 
+/// Save the current exception state in "estate"
+void exception_state_save(exception_state_T *estate)
+{
+  estate->estate_current_exception = current_exception;
+  estate->estate_did_throw = did_throw;
+  estate->estate_need_rethrow = need_rethrow;
+  estate->estate_trylevel = trylevel;
+}
+
+/// Restore the current exception state from "estate"
+void exception_state_restore(exception_state_T *estate)
+{
+  if (current_exception == NULL) {
+    current_exception = estate->estate_current_exception;
+  }
+  did_throw |= estate->estate_did_throw;
+  need_rethrow |= estate->estate_need_rethrow;
+  trylevel |= estate->estate_trylevel;
+}
+
+/// Clear the current exception state
+void exception_state_clear(void)
+{
+  current_exception = NULL;
+  did_throw = false;
+  need_rethrow = false;
+  trylevel = 0;
+}
+
 // Flags specifying the message displayed by report_pending.
 #define RP_MAKE         0
 #define RP_RESUME       1