From 6ff1560487b6deaac60c0e385fd0c4496a1c673c Mon Sep 17 00:00:00 2001
From: rlar <rlar>
Date: Sat, 2 May 2015 12:33:45 +0200
Subject: [PATCH] frontend/cpitf.c, free a temporary vector which was left in
 `cp_istrue()'

reported by Marcel Hendrix.

Using conditional expressions within a .control sequence
  left some garbage vectors in the current plot.

For example

> let ix = 0
>
> while ix < 2
>   let ix = ix + 1
> end
>
> display

"display" reported a variable named "ix < 2"
which was an internal temporary value in said function `cp_istrue()'
---
 src/frontend/cpitf.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/frontend/cpitf.c b/src/frontend/cpitf.c
index 28fe87906..d1aaeff2c 100644
--- a/src/frontend/cpitf.c
+++ b/src/frontend/cpitf.c
@@ -315,7 +315,12 @@ cp_istrue(wordlist *wl)
     v = ft_evaluate(names);
 
     rv = !vec_iszero(v);
-    free_pnode(names);
+
+    /* va: garbage collection for v, if pnode names is no simple value */
+    if (names->pn_value == NULL && v != NULL)
+        vec_free(v);
+    free_pnode(names); /* free also v, if pnode names is simple value */
+
     return rv;
 }