vim-patch:8.2.2764: memory leak when default function argument is allocated

Problem:    Memory leak when default function argument is allocated.
Solution:   Free the expression result.
https://github.com/vim/vim/commit/b47bed2f7ada4dfae78f76f27473b83507e40315

1 files changed, 10 insertions, 1 deletions

diff --git a/src/nvim/eval/userfunc.c b/src/nvim/eval/userfunc.c
index 689d05e079..00260bc3f7 100644
--- a/src/nvim/eval/userfunc.c
+++ b/src/nvim/eval/userfunc.c
@@ -833,6 +833,8 @@ void call_user_func(ufunc_T *fp, int argcount, typval_T *argvars,
   bool islambda = false;
   char_u numbuf[NUMBUFLEN];
   char_u      *name;
+  typval_T *tv_to_free[MAX_FUNC_ARGS];
+  int tv_to_free_len = 0;
   proftime_T wait_start;
   proftime_T call_start;
   int started_profiling = false;
@@ -985,6 +987,11 @@ void call_user_func(ufunc_T *fp, int argcount, typval_T *argvars,
     v->di_tv = isdefault ? def_rettv : argvars[i];
     v->di_tv.v_lock = VAR_FIXED;
 
+    if (isdefault) {
+      // Need to free this later, no matter where it's stored.
+      tv_to_free[tv_to_free_len++] = &v->di_tv;
+    }
+
     if (addlocal) {
       // Named arguments can be accessed without the "a:" prefix in lambda
       // expressions. Add to the l: dict.
@@ -1209,7 +1216,9 @@ void call_user_func(ufunc_T *fp, int argcount, typval_T *argvars,
 
   did_emsg |= save_did_emsg;
   depth--;
-
+  for (int i = 0; i < tv_to_free_len; i++) {
+    tv_clear(tv_to_free[i]);
+  }
   cleanup_function_call(fc);
 
   if (--fp->uf_calls <= 0 && fp->uf_refcount <= 0) {