ZJIT: Print a message about ZJIT_RB_BUG when unused (#13852)

1 files changed, 2 insertions, 0 deletions

diff --git a/zjit/src/cruby.rs b/zjit/src/cruby.rs
index 459c7d7d5d..eba8af318f 100644
--- a/zjit/src/cruby.rs
+++ b/zjit/src/cruby.rs
@@ -860,6 +860,8 @@ pub fn rb_bug_panic_hook() {
             let panic_message = &format!("{}", panic_info)[..];
             let len = std::cmp::min(0x100, panic_message.len()) as c_int;
             unsafe { rb_bug(b"ZJIT: %*s\0".as_ref().as_ptr() as *const c_char, len, panic_message.as_ptr()); }
+        } else {
+            eprintln!("note: run with `ZJIT_RB_BUG=1` environment variable to display a Ruby backtrace");
         }
     }));
 }