mirror of https://github.com/ruby/ruby.git synced 2022-11-09 12:17:21 -05:00

Aaron Patterson 62ce8f96cd

This reverts commit 02b216e5a7.
This reverts commit 9b8825b6f9.

I found that combining sweep and move is not safe.  I don't think that
we can do compaction concurrently with _anything_ unless there is a read
barrier installed.

Here is a simple example.  A class object is freed, and during it's free
step, it tries to remove itself from its parent's subclass list.
However, during the sweep step, the parent class was moved and the
"currently being freed" class didn't have references updated yet.  So we
get a segv like this:

```
(lldb) bt
* thread #1, name = 'ruby', stop reason = signal SIGSEGV
  * frame #0: 0x0000560763e344cb ruby`rb_st_lookup at st.c:320:43
    frame #1: 0x0000560763e344cb ruby`rb_st_lookup(tab=0x2f7469672f6e6f72, key=3809, value=0x0000560765bf2270) at st.c:1010
    frame #2: 0x0000560763e8f16a ruby`rb_search_class_path at variable.c:99:9
    frame #3: 0x0000560763e8f141 ruby`rb_search_class_path at variable.c:145
    frame #4: 0x0000560763e8f141 ruby`rb_search_class_path(klass=94589785585880) at variable.c:191
    frame #5: 0x0000560763ec744e ruby`rb_vm_bugreport at vm_dump.c:996:17
    frame #6: 0x0000560763f5b958 ruby`rb_bug_for_fatal_signal at error.c:675:5
    frame #7: 0x0000560763e27dad ruby`sigsegv(sig=<unavailable>, info=<unavailable>, ctx=<unavailable>) at signal.c:955:5
    frame #8: 0x00007f8b891d33c0 libpthread.so.0`___lldb_unnamed_symbol1$$libpthread.so.0 + 1
    frame #9: 0x0000560763efa8bb ruby`rb_class_remove_from_super_subclasses(klass=94589790314280) at class.c:93:56
    frame #10: 0x0000560763d10cb7 ruby`gc_sweep_step at gc.c:2674:2
    frame #11: 0x0000560763d1187b ruby`gc_sweep at gc.c:4540:2
    frame #12: 0x0000560763d101f0 ruby`gc_start at gc.c:6797:6
    frame #13: 0x0000560763d15153 ruby`rb_gc_compact at gc.c:7479:12
    frame #14: 0x0000560763eb4eb8 ruby`vm_exec_core at vm_insnhelper.c:5183:13
    frame #15: 0x0000560763ea9bae ruby`rb_vm_exec at vm.c:1953:22
    frame #16: 0x0000560763eac08d ruby`rb_yield at vm.c:1132:9
    frame #17: 0x0000560763edb4f2 ruby`rb_ary_collect at array.c:3186:9
    frame #18: 0x0000560763e9ee15 ruby`vm_call_cfunc_with_frame at vm_insnhelper.c:2575:12
    frame #19: 0x0000560763eb2e66 ruby`vm_exec_core at vm_insnhelper.c:4177:11
    frame #20: 0x0000560763ea9bae ruby`rb_vm_exec at vm.c:1953:22
    frame #21: 0x0000560763eac08d ruby`rb_yield at vm.c:1132:9
    frame #22: 0x0000560763edb4f2 ruby`rb_ary_collect at array.c:3186:9
    frame #23: 0x0000560763e9ee15 ruby`vm_call_cfunc_with_frame at vm_insnhelper.c:2575:12
    frame #24: 0x0000560763eb2e66 ruby`vm_exec_core at vm_insnhelper.c:4177:11
    frame #25: 0x0000560763ea9bae ruby`rb_vm_exec at vm.c:1953:22
    frame #26: 0x0000560763ceee01 ruby`rb_ec_exec_node(ec=0x0000560765afa530, n=0x0000560765b088e0) at eval.c:296:2
    frame #27: 0x0000560763cf3b7b ruby`ruby_run_node(n=0x0000560765b088e0) at eval.c:354:12
    frame #28: 0x0000560763cee4a3 ruby`main(argc=<unavailable>, argv=<unavailable>) at main.c:50:9
    frame #29: 0x00007f8b88e560b3 libc.so.6`__libc_start_main + 243
    frame #30: 0x0000560763cee4ee ruby`_start + 46
(lldb) f 9
frame #9: 0x0000560763efa8bb ruby`rb_class_remove_from_super_subclasses(klass=94589790314280) at class.c:93:56
   90
   91  		*RCLASS_EXT(klass)->parent_subclasses = entry->next;
   92  		if (entry->next) {
-> 93  		    RCLASS_EXT(entry->next->klass)->parent_subclasses = RCLASS_EXT(klass)->parent_subclasses;
   94  		}
   95  		xfree(entry);
   96  	    }
(lldb) command script import -r misc/lldb_cruby.py
lldb scripts for ruby has been installed.
(lldb) rp entry->next->klass
(struct RMoved) $1 = (flags = 30, destination = 94589792806680, next = 94589784369160)
(lldb)
```

2020-06-09 13:53:18 -07:00

6.5 KiB

Raw Blame History

NEWS for Ruby 2.8.0 (tentative; to be 3.0.0)

This document is a list of user visible feature changes since the 2.7.0 release, except for bug fixes.

Note that each entry is kept so brief that no reason behind or reference information is supplied with. For a full list of changes with all sufficient information, see the ChangeLog file or Redmine (e.g. https://bugs.ruby-lang.org/issues/$FEATURE_OR_BUG_NUMBER).

Language changes

Keyword arguments are now separated from positional arguments. Code that resulted in deprecation warnings in Ruby 2.7 will now result in ArgumentError or different behavior. [Feature #14183]

Procs accepting a single rest argument and keywords are no longer subject to autosplatting. This now matches the behavior of Procs accepting a single rest argument and no keywords. [Feature #16166]

pr = proc{|*a, **kw| [a, kw]}

pr.call([1])
# 2.7 => [[1], {}]
# 3.0 => [[[1]], {}]

pr.call([1, {a: 1}])
# 2.7 => [[1], {:a=>1}] # and deprecation warning
# 3.0 => [[[1, {:a=>1}]], {}]

$SAFE is now a normal global variable with no special behavior. [Feature #16131]
yield in singleton class definitions in methods is now a SyntaxError instead of a warning. yield in a class definition outside of a method is now a SyntaxError instead of a LocalJumpError. [Feature #15575]
Rightward assignment statement is added. [EXPERIMENTAL] [Feature #15921]
```
fib(10) => x
```
Endless method definition is added. [EXPERIMENTAL] [Feature #16746]
```
def square(x) = x * x
```

Command line options

`--help` option

When the environment variable RUBY_PAGER or PAGER is present and has non-empty value, and the standard input and output are tty, --help option shows the help message via the pager designated by the value. [Feature #16754]

Core classes updates

Outstanding ones only.

Dir
- Modified method
  - Dir.glob and Dir.[] now sort the results by default, and accept sort: keyword option. [Feature #8709]
Hash
- Modified method
  - Hash#transform_keys now accepts a hash that maps keys to new keys. [Feature #16274]
Kernel
- Modified method
  - Kernel#clone when called with freeze: false keyword will call #initialize_clone with the freeze: false keyword. [Bug #14266]
  - Kernel#eval when called with two arguments will use "(eval)" for __FILE__ and 1 for __LINE__ in the evaluated code. [Bug #4352]
Module
- Modified method
  - Module#include now includes the arguments in modules and classes that have already included or prepended the receiver, mirroring the behavior if the arguments were included in the receiver before the other modules and classes included or prepended the receiver. [Feature #9573]
Symbol
- Modified method
  - Symbol#to_proc now returns a lambda Proc. [Feature #16260]

Stdlib updates

Outstanding ones only.

RubyGems
- Update to RubyGems 3.2.0.pre1
Bundler
- Update to Bundler 2.2.0.dev
Net::HTTP
- New method
  - Add Net::HTTP#verify_hostname= and Net::HTTP#verify_hostname to skip hostname verification. [Feature #16555]
- Modified method
  - Net::HTTP.get, Net::HTTP.get_response, and Net::HTTP.get_print can take request headers as a Hash in the second argument when the first argument is a URI.

Compatibility issues

Excluding feature bug fixes.

Regexp literals are frozen [Feature #8948] [Feature #16377]
```
/foo/.frozen? #=> true
```
Bundled gems
- net-telnet and xmlrpc have been removed from the bundled gems. If you are interested in maintaining them, please comment on your plan to https://github.com/ruby/xmlrpc or https://github.com/ruby/net-telnet.
EXPERIMENTAL: Hash#each consistently yields a 2-element array [Bug #12706]
- Now { a: 1 }.each(&->(k, v) { }) raises an ArgumentError due to lambda's arity check.
- This is experimental; if it brings a big incompatibility issue, it may be reverted until 2.8/3.0 release.
When writing to STDOUT redirected to a closed pipe, no broken pipe error message will be shown now. [Feature #14413]
TRUE/FALSE/NIL constants are no longer defined.

Stdlib compatibility issues