From: "jemmai (Jemma Issroff) via ruby-core" <ruby-core@...>
Date: 2023-09-20T18:10:08+00:00
Subject: [ruby-core:114849] [Ruby master Bug#19895] Memory leak in Ripper#sexp_raw called with invalid syntax

Issue #19895 has been updated by jemmai (Jemma Issroff).

Status changed from Open to Closed

Duplicate of [#19835]

----------------------------------------
Bug #19895: Memory leak in Ripper#sexp_raw called with invalid syntax
https://bugs.ruby-lang.org/issues/19895#change-104694

* Author: jemmai (Jemma Issroff)
* Status: Closed
* 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



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