Issue #19895 has been reported by jemmai (Jemma Issroff). ---------------------------------------- Bug #19895: Memory leak in Ripper#sexp_raw called with invalid syntax https://bugs.ruby-lang.org/issues/19895 * Author: jemmai (Jemma Issroff) * Status: Open * Priority: Normal * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- There is a memory leak in `Ripper#sexp_raw` with invalid syntax I used [the ruby_memcheck gem](https://github.com/Shopify/ruby_memcheck) to find this leak. # Script to reproduce: ``` $ ruby_memcheck -e 'require "ripper"; Ripper.sexp_raw("break 1,;")' ``` # Stack trace ``` 64 bytes in 1 blocks are definitely lost in loss record 8,335 of 11,879 malloc (at /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so) objspace_xmalloc0 (gc.c:11465) *vtable_alloc_gen (ripper.y:6209) *local_push.constprop.0 (ripper.y:12587) *ripper_yyparse (ripper.y:1329) *ripper_parse0 (ripper.y:13817) rb_ensure (eval.c:997) *ripper_parse (ripper.y:13855) vm_call_cfunc_with_frame (vm_insnhelper.c:3037) vm_sendish (vm_insnhelper.c:4751) vm_exec_core (insns.def:778) rb_vm_exec (vm.c:2220) rb_ec_exec_node (eval.c:280) ruby_run_node (eval.c:321) main (main.c:47) 88 (24 direct, 64 indirect) bytes in 1 blocks are definitely lost in loss record 8,508 of 11,879 malloc (at /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so) objspace_xmalloc0 (gc.c:11465) *vtable_alloc_gen (ripper.y:6206) *local_push.constprop.0 (ripper.y:12586) *ripper_yyparse (ripper.y:1329) *ripper_parse0 (ripper.y:13817) rb_ensure (eval.c:997) *ripper_parse (ripper.y:13855) vm_call_cfunc_with_frame (vm_insnhelper.c:3037) vm_sendish (vm_insnhelper.c:4751) vm_exec_core (insns.def:778) rb_vm_exec (vm.c:2220) rb_ec_exec_node (eval.c:280) ruby_run_node (eval.c:321) main (main.c:47) Valgrind reported errors (e.g. memory leak or use-after-free) (RuntimeError) ``` # Expected behavior The [`Ripper#sexp_raw` docs](https://docs.ruby-lang.org/en/master/Ripper.html#method-c-sexp_raw) state that "By default, this method does not handle syntax errors in src, returning nil in such cases." Expected behavior, according to the documentation, would be `nil` returned without any memory leak -- https://bugs.ruby-lang.org/