refactor(exit): pass error message to preserve_exit() (#22097)

Problem:
1. Some calls to preserve_exit() don't put a message in IObuff, so the
   IObuff printed by preserve_exit() contains unrelated information.
2. If a TUI client runs out of memory or receives a deadly signal, the
   error message is shown on alternate screen and cannot be easily seen
   because the TUI exits alternate screen soon afterwards.

Solution:
Pass error message to preserve_exit() and exit alternate screen before
printing it.

Note that this doesn't fix the problem that server error messages cannot
be easily seen on exit. This is tracked in #21608 and #21843.

1 files changed, 4 insertions, 11 deletions

diff --git a/src/nvim/memory.c b/src/nvim/memory.c
index 5356300382..4e799dfd08 100644
--- a/src/nvim/memory.c
+++ b/src/nvim/memory.c
@@ -121,9 +121,7 @@ void *xmalloc(size_t size)
 {
   void *ret = try_malloc(size);
   if (!ret) {
-    os_errmsg(e_outofmem);
-    os_errmsg("\n");
-    preserve_exit();
+    preserve_exit(e_outofmem);
   }
   return ret;
 }
@@ -152,9 +150,7 @@ void *xcalloc(size_t count, size_t size)
     try_to_free_memory();
     ret = calloc(allocated_count, allocated_size);
     if (!ret) {
-      os_errmsg(e_outofmem);
-      os_errmsg("\n");
-      preserve_exit();
+      preserve_exit(e_outofmem);
     }
   }
   return ret;
@@ -174,9 +170,7 @@ void *xrealloc(void *ptr, size_t size)
     try_to_free_memory();
     ret = realloc(ptr, allocated_size);
     if (!ret) {
-      os_errmsg(e_outofmem);
-      os_errmsg("\n");
-      preserve_exit();
+      preserve_exit(e_outofmem);
     }
   }
   return ret;
@@ -194,8 +188,7 @@ void *xmallocz(size_t size)
 {
   size_t total_size = size + 1;
   if (total_size < size) {
-    os_errmsg(_("Vim: Data too large to fit into virtual memory space\n"));
-    preserve_exit();
+    preserve_exit(_("Vim: Data too large to fit into virtual memory space\n"));
   }
 
   void *ret = xmalloc(total_size);