merge revision(s) ac00bdc8a8ac2c62a94dd36a7784d15bbcb7df19: [Backport #15821]

	Do not modify shared array
	
	[Bug #15821]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_5@67759 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 17 insertions, 2 deletions

diff --git a/ruby.c b/ruby.c
index 5a7032ab7b..4ff30cceca 100644
--- a/ruby.c
+++ b/ruby.c
@@ -1604,8 +1604,12 @@ process_options(int argc, char **argv, ruby_cmdline_options_t *opt)
     rb_obj_freeze(opt->script_name);
     if (IF_UTF8_PATH(uenc != lenc, 1)) {
 	long i;
-	VALUE load_path = GET_VM()->load_path;
+        rb_vm_t *vm = GET_VM();
+        VALUE load_path = vm->load_path;
 	const ID id_initial_load_path_mark = INITIAL_LOAD_PATH_MARK;
+        int modifiable = FALSE;
+
+        rb_get_expanded_load_path();
 	for (i = 0; i < RARRAY_LEN(load_path); ++i) {
 	    VALUE path = RARRAY_AREF(load_path, i);
 	    int mark = rb_attr_get(path, id_initial_load_path_mark) == path;
@@ -1617,8 +1621,15 @@ process_options(int argc, char **argv, ruby_cmdline_options_t *opt)
 	    path = rb_enc_associate(rb_str_dup(path), lenc);
 #endif
 	    if (mark) rb_ivar_set(path, id_initial_load_path_mark, path);
+            if (!modifiable) {
+                rb_ary_modify(load_path);
+                modifiable = TRUE;
+            }
 	    RARRAY_ASET(load_path, i, path);
 	}
+        if (modifiable) {
+            rb_ary_replace(vm->load_path_snapshot, load_path);
+        }
     }
     Init_ext();		/* load statically linked extensions before rubygems */
     if (opt->features & FEATURE_BIT(gems)) {
diff --git a/test/ruby/test_gc.rb b/test/ruby/test_gc.rb
index 7a6309b6a3..8873813017 100644
--- a/test/ruby/test_gc.rb
+++ b/test/ruby/test_gc.rb
@@ -383,6 +383,10 @@ class TestGc < Test::Unit::TestCase
     end;
   end
 
+  def test_gc_stress_at_startup
+    assert_in_out_err([{"RUBY_DEBUG"=>"gc_stress"}], '', [], [], '[Bug #15784]', success: true)
+  end
+
   def test_gc_disabled_start
     begin
       disabled = GC.disable
diff --git a/version.h b/version.h
index 220de0f4b8..7043aa168d 100644
--- a/version.h
+++ b/version.h
@@ -1,6 +1,6 @@
 #define RUBY_VERSION "2.5.6"
 #define RUBY_RELEASE_DATE "2019-08-26"
-#define RUBY_PATCHLEVEL 178
+#define RUBY_PATCHLEVEL 179
 
 #define RUBY_RELEASE_YEAR 2019
 #define RUBY_RELEASE_MONTH 8