From 84e7b08a631bac0f209259fb74ee463593ef6e8c Mon Sep 17 00:00:00 2001
From: Benjamin Peinhardt <benjaminpeinhardt@gmail.com>
Date: Wed, 5 Jan 2022 11:23:06 -0600
Subject: [PATCH] Oops two lines of unsafe code and I do a double free

---
 src/xpath.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/xpath.rs b/src/xpath.rs
index b3f51ce6e0..0b1356f7a4 100644
--- a/src/xpath.rs
+++ b/src/xpath.rs
@@ -257,6 +257,8 @@ pub fn xml_xpath_compiles(xpath: &str) -> bool {
   let c_xpath = CString::new(xpath).unwrap();
     let xml_xpath_comp_expr_ptr = unsafe { xmlXPathCompile(c_xpath.as_bytes().as_ptr()) };
     let result = !xml_xpath_comp_expr_ptr.is_null();
-    unsafe { libc::free(xml_xpath_comp_expr_ptr as *mut c_void); }
+    if result {
+      unsafe { libc::free(xml_xpath_comp_expr_ptr as *mut c_void); }
+    }
     result
 }