Exact

Exact Union RegExp

usa 689a6a0a76 merge revision(s) 3f9562015e651735bfc2fdd14e8f6963b673e22a,c06ddfee878524168e4af07443217ed2f8d0954b,3b3b4a44e5: [Backport #15792] ... Get rid of indirect sharing * string.c (str_duplicate): share the root shared string if the original string is already sharing, so that all shared strings refer the root shared string directly. indirect sharing can cause a dangling pointer. [Bug #15792] str_duplicate: Don't share with a frozen shared string This is a follow up for 3f9562015e. Before this commit, it was possible to create a shared string which shares with another shared string by passing a frozen shared string to `str_duplicate`. Such string looks like: ``` -------- ----------------- | root | ------ owns -----> | root's buffer | -------- ----------------- ^ ^ ^ ----------- | | | shared1 | ------ references ----- | ----------- | ^ | ----------- | | shared2 | ------ references --------- ----------- ``` This is bad news because `rb_fstring(shared2)` can make `shared1` independent, which severs the reference from `shared1` to `root`: ```c /* from fstr_update_callback() */ str = str_new_frozen(rb_cString, shared2); /* can return shared1 */ if (STR_SHARED_P(str)) { /* shared1 is also a shared string */ str_make_independent(str); /* no frozen check */ } ``` If `shared1` was the only reference to `root`, then `root` can be reclaimed by the GC, leaving `shared2` in a corrupted state: ``` ----------- -------------------- | shared1 | -------- owns --------> | shared1's buffer | ----------- -------------------- ^ | ----------- ------------------------- | shared2 | ------ references ----> | root's buffer (freed) | ----------- ------------------------- ``` Here is a reproduction script for the situation this commit fixes. ```ruby a = ('a' * 24).strip.freeze.strip -a p a 4.times { GC.start } p a ``` - string.c (str_duplicate): always share with the root string when the original is a shared string. - test_rb_str_dup.rb: specifically test `rb_str_dup` to make sure it does not try to share with a shared string. [Bug #15792] Closes: https://github.com/ruby/ruby/pull/2159 Update dependencies git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_5@67766 b2dd03c8-39d4-4d8f-98ff-823fe69b080e		2019-08-26 15:58:57 +00:00
..
test_capacity.rb	Fixed misspelling words.	2017-10-22 11:27:06 +00:00
test_coderange.rb	Add frozen_string_literal: false for all files	2015-12-16 05:07:31 +00:00
test_cstr.rb	string.c: return reallocated pointer	2016-05-30 07:20:28 +00:00
test_ellipsize.rb	Add frozen_string_literal: false for all files	2015-12-16 05:07:31 +00:00
test_enc_associate.rb	Add FrozenError as a subclass of RuntimeError	2017-12-12 00:46:34 +00:00
test_enc_str_buf_cat.rb	Add frozen_string_literal: false for all files	2015-12-16 05:07:31 +00:00
test_external_new.rb	Add test for Bug::String.buf_new	2017-12-03 12:06:16 +00:00
test_fstring.rb	test_fstring.rb: fix exception	2016-11-12 13:24:23 +00:00
test_modify_expand.rb	test_modify_expand.rb: skip if no overflow	2016-12-22 23:20:00 +00:00
test_nofree.rb	Add frozen_string_literal: false for all files	2015-12-16 05:07:31 +00:00
test_normalize.rb	Add frozen_string_literal: false for all files	2015-12-16 05:07:31 +00:00
test_qsort.rb	Add frozen_string_literal: false for all files	2015-12-16 05:07:31 +00:00
test_rb_str_dup.rb	merge revision(s) 3f9562015e651735bfc2fdd14e8f6963b673e22a,c06ddfee878524168e4af07443217ed2f8d0954b,3b3b4a44e5: [Backport #15792]	2019-08-26 15:58:57 +00:00
test_set_len.rb	string.c: fix buffer overflow check condition in rb_str_set_len()	2016-09-13 07:08:15 +00:00