coverity/62615: fix leak in write_reg_contents_ex

Coverity detected a memory leak caused by not free'ing the value returned by
get_expr_line_src (basically vim_strsave(expr_line)). Replaced the copying
with direct manipulation of expr_line, since that also happens in other
parts of the codebase.

NOTE: I'm aware that this has different behaviour than vim_strnsave, namely
vim_strnsave always allocates `len` bytes, even if the string is shorter. I
don't see how that behaviour is helpful here though.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/nvim/search.c b/src/nvim/search.c
index 5ba30eeb00..08fdfa4b63 100644
--- a/src/nvim/search.c
+++ b/src/nvim/search.c
@@ -375,14 +375,14 @@ void reset_search_dir(void)
  * Set the last search pattern.  For ":let @/ =" and viminfo.
  * Also set the saved search pattern, so that this works in an autocommand.
  */
-void set_last_search_pat(char_u *s, int idx, int magic, int setlast)
+void set_last_search_pat(const char_u *s, int idx, int magic, int setlast)
 {
   free(spats[idx].pat);
   /* An empty string means that nothing should be matched. */
   if (*s == NUL)
     spats[idx].pat = NULL;
   else
-    spats[idx].pat = vim_strsave(s);
+    spats[idx].pat = (char_u *) xstrdup((char *) s);
   spats[idx].magic = magic;
   spats[idx].no_scs = FALSE;
   spats[idx].off.dir = '/';