From 971857c3326b163c45f02922bb5c5143d54e520d Mon Sep 17 00:00:00 2001
From: John Hawthorn <john@hawthorn.email>
Date: Thu, 9 Jul 2020 14:59:59 -0700
Subject: [PATCH] Fix method name escaping in ObjectSpace.dump

It's possible to define methods with any name, even if the parser
doesn't support it and it can only be used with ex. send.

This fixes an issue where invalid JSON was output from ObjectSpace.dump
when a method name needed escaping.
---
 ext/objspace/objspace_dump.c   |  3 ++-
 test/objspace/test_objspace.rb | 18 ++++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/ext/objspace/objspace_dump.c b/ext/objspace/objspace_dump.c
index d5996f67a8..f7b9b0b26c 100644
--- a/ext/objspace/objspace_dump.c
+++ b/ext/objspace/objspace_dump.c
@@ -313,7 +313,8 @@ dump_object(VALUE obj, struct dump_config *dc)
 	dump_append(dc, ", \"file\":\"%s\", \"line\":%lu", ainfo->path, ainfo->line);
 	if (RTEST(ainfo->mid)) {
 	    VALUE m = rb_sym2str(ainfo->mid);
-	    dump_append(dc, ", \"method\":\"%s\"", RSTRING_PTR(m));
+	    dump_append(dc, ", \"method\":");
+	    dump_append_string_value(dc, m);
 	}
 	dump_append(dc, ", \"generation\":%"PRIuSIZE, ainfo->generation);
     }
diff --git a/test/objspace/test_objspace.rb b/test/objspace/test_objspace.rb
index 5073bbee06..42fbc3e03c 100644
--- a/test/objspace/test_objspace.rb
+++ b/test/objspace/test_objspace.rb
@@ -362,6 +362,24 @@ class TestObjSpace < Test::Unit::TestCase
     end
   end
 
+  def test_dump_escapes_method_name
+    method_name = "foo\"bar"
+    klass = Class.new do
+      define_method(method_name) { "TEST STRING" }
+    end
+    ObjectSpace.trace_object_allocations_start
+
+    obj = klass.new.send(method_name)
+
+    dump = ObjectSpace.dump(obj)
+    assert_includes dump, '"method":"foo\"bar"'
+
+    parsed = JSON.parse(dump)
+    assert_equal "foo\"bar", parsed["method"]
+  ensure
+    ObjectSpace.trace_object_allocations_stop
+  end
+
   def test_dump_reference_addresses_match_dump_all_addresses
     assert_in_out_err(%w[-robjspace], "#{<<-"begin;"}\n#{<<-'end;'}") do |output, error|
       begin;