Exact

Exact Union RegExp

nagachika f5930c8717 merge revision(s) 3f9562015e651735bfc2fdd14e8f6963b673e22a,c06ddfee878524168e4af07443217ed2f8d0954b,3b3b4a44e57dfe03ce3913009d69a33d6f6100be: [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_6@67731 b2dd03c8-39d4-4d8f-98ff-823fe69b080e		2019-08-07 11:45:24 +00:00
..
capacity.c	Init functions should have prefix to avoid confliction.	2017-12-03 08:02:56 +00:00
coderange.c	UNREACHABLE_RETURN	2018-07-24 05:38:07 +00:00
cstr.c	internal.h: remove dependecy on ruby/encoding.h	2018-01-09 06:24:11 +00:00
depend	merge revision(s) 3f9562015e651735bfc2fdd14e8f6963b673e22a,c06ddfee878524168e4af07443217ed2f8d0954b,3b3b4a44e57dfe03ce3913009d69a33d6f6100be: [Backport #15792]	2019-08-07 11:45:24 +00:00
ellipsize.c	Init functions should have prefix to avoid confliction.	2017-12-03 08:02:56 +00:00
enc_associate.c	Init functions should have prefix to avoid confliction.	2017-12-03 08:02:56 +00:00
enc_str_buf_cat.c	Init functions should have prefix to avoid confliction.	2017-12-03 08:02:56 +00:00
extconf.rb	auto_ext.rb	2016-05-29 03:08:45 +00:00
fstring.c	Init functions should have prefix to avoid confliction.	2017-12-03 08:02:56 +00:00
init.c	Init functions should have prefix to avoid confliction.	2017-12-03 08:02:56 +00:00
modify.c	Init functions should have prefix to avoid confliction.	2017-12-03 08:02:56 +00:00
new.c	Init functions should have prefix to avoid confliction.	2017-12-03 08:02:56 +00:00
nofree.c	Init functions should have prefix to avoid confliction.	2017-12-03 08:02:56 +00:00
normalize.c	Init functions should have prefix to avoid confliction.	2017-12-03 08:02:56 +00:00
qsort.c	Init functions should have prefix to avoid confliction.	2017-12-03 08:02:56 +00:00
rb_str_dup.c	merge revision(s) 3f9562015e651735bfc2fdd14e8f6963b673e22a,c06ddfee878524168e4af07443217ed2f8d0954b,3b3b4a44e57dfe03ce3913009d69a33d6f6100be: [Backport #15792]	2019-08-07 11:45:24 +00:00
set_len.c	Init functions should have prefix to avoid confliction.	2017-12-03 08:02:56 +00:00