vim-patch:8.2.0056: execution stack is incomplete and inefficient

Problem:    Execution stack is incomplete and inefficient.
Solution:   Introduce a proper execution stack and use it instead of
            sourcing_name/sourcing_lnum.  Create a string only when used.
https://github.com/vim/vim/commit/1a47ae32cdc19b0fd5a82e19fe5fddf45db1a506

Omit test_debugger.vim: superseded by later patches.
Omit check_map_keycodes(): N/A.
Omit kword_test.c: N/A (converted to a unit test).

1 files changed, 9 insertions, 6 deletions

diff --git a/src/nvim/testing.c b/src/nvim/testing.c
index 69b687e44f..de6d445ba3 100644
--- a/src/nvim/testing.c
+++ b/src/nvim/testing.c
@@ -7,6 +7,7 @@
 #include "nvim/eval/encode.h"
 #include "nvim/ex_docmd.h"
 #include "nvim/os/os.h"
+#include "nvim/runtime.h"
 #include "nvim/testing.h"
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
@@ -17,21 +18,23 @@
 static void prepare_assert_error(garray_T *gap)
 {
   char buf[NUMBUFLEN];
+  char *sname = estack_sfile();
 
   ga_init(gap, 1, 100);
-  if (sourcing_name != NULL) {
-    ga_concat(gap, (char *)sourcing_name);
-    if (sourcing_lnum > 0) {
+  if (sname != NULL) {
+    ga_concat(gap, sname);
+    if (SOURCING_LNUM > 0) {
       ga_concat(gap, " ");
     }
   }
-  if (sourcing_lnum > 0) {
-    vim_snprintf(buf, ARRAY_SIZE(buf), "line %" PRId64, (int64_t)sourcing_lnum);
+  if (SOURCING_LNUM > 0) {
+    vim_snprintf(buf, ARRAY_SIZE(buf), "line %" PRId64, (int64_t)SOURCING_LNUM);
     ga_concat(gap, buf);
   }
-  if (sourcing_name != NULL || sourcing_lnum > 0) {
+  if (sname != NULL || SOURCING_LNUM > 0) {
     ga_concat(gap, ": ");
   }
+  xfree(sname);
 }
 
 /// Append "p[clen]" to "gap", escaping unprintable characters.