Users can now switch to their own implementation of GEM.
However, we do not guarantee that this will not be a problem in the current situation.
This may need to be improved in the future.
Normal return of control from the `mrb_sys_fail()` function has unexpected results.
Example: double free, malloc with huge size used as error integer
The following is an example of an actual crash:
```console
% cat crash.rb
def SystemCallError._sys_fail(*a)
nil
end
File.readlink("/404")
% bin/mruby crash.rb
zsh: segmentation fault (core dumped) bin/mruby crash.rb
```
Internal functions can only be called from within the library.
Functions listed in `mruby/internal.h` can be called from:
* core (src/*.c)
* gems (mrbgems/**/*.c)
But not from the application linked with `libmruby`.
Since the possible values of the backtrace are limited to `nil`, `RData`, and `RAray`, they are now stored as object pointers.
This change saves memory by eliminating the need to use instance variables for common exceptions.
ref. #2485
There is no need to limit the type to `struct RString`.
Also, the `MRB_EXC_MESG_STRING_FLAG` flag can be eliminated by checking if `struct RException::mesg` is `NULL` or not.
ref. #2485
To more consistent names.
* mrb_num_plus() -> mrb_num_add()
* mrb_num_minus() -> mrb_num_sub()
Since no one seems to use those functions, there should be no problem.
We added migration macros for compatibility for safety.
ref. #2485
The `SystemCallError#to_s` method also needed to be modified, but since it has no functional difference from the `Exception#to_s` method, it will be removed.
It seems to be preferable to be able to handle pointers of type `char` as well.
For this purpose, `mrb_nanbox_tt_inline` has been reorganized.
- `MRB_NANBOX_TT_POINTER` has been split into `MRB_NANBOX_TT_OBJECT` and `MRB_NANBOX_TT_CPTR`
- `MRB_NANBOX_TT_SYMBOL` has been merged into `MRB_NANBOX_TT_MISC`
The main purpose is to increase the chances of finding presym and to prevent errors due to C++11 lambda expressions.
- The argument to receive the class may be written, for example, `mrb_class_get()`.
- The argument that receives the implementation function of the method may be a C++ lambda expression.
In this case, if multiple variable declarations are separated by colons, the preprocessor will recognize them as argument delimiters and report an error.
This patch prevents it from happening.
```c++
// When preprocessing...
func([] { int x, y, z; })
// ^^^^^^^^^^ 1st argument?
// ^ 2nd argument?
// ^^^^ 3rd argument?
```
The `__id__` method implemented in the C function has `MRB_ARGS_NONE()` specified, but it is also effective in the following cases.
```ruby
p nil.__id__ opts: 1 rescue p :a
p nil.method(:__id__).call 1 rescue p :b
p nil.method(:__id__).call opts: 1 rescue p :c
p nil.method(:__id__).to_proc.call 1 rescue p :d
p nil.method(:__id__).to_proc.call opts: 1 rescue p :e
p nil.method(:__id__).unbind.bind_call nil, 1 rescue p :f
p nil.method(:__id__).unbind.bind_call nil, opts: 1 rescue p :g
p nil.__send__ :__id__, 1 rescue p :h
p nil.__send__ :__id__, opts: 1 rescue p :i
```
After applying this patch, all items will output symbols in the same way as CRuby.
For this purpose, add `MRB_PROC_NOARG` to `struct RProc::flags`.
```console
% c++ -xc++ -std=c++03 -S -Iinclude -DMRB_NAN_BOXING -DMRB_NO_PRESYM -o- src/array.c > /dev/null
In file included from src/array.c:7:
In file included from include/mruby.h:115:
In file included from include/mruby/value.h:201:
include/mruby/boxing_nan.h:95:12: error: cannot initialize return object of type 'enum mrb_vtype' with an rvalue of type 'int'
return (enum mrb_vtype)(o.u >> 8) & 0x1f;
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
```
Adding `MRB_WORDBOX_NO_FLOAT_TRUNCATE` to the build configuration in 32-bit CPU mode had a double definition.
```console
% cat myconf.rb
MRuby::Build.new do
toolchain "clang"
defines << "MRB_WORDBOX_NO_FLOAT_TRUNCATE"
cc.flags << "-m32"
linker.flags << "-m32"
enable_debug
end
% rake CONFIG=myconf.rb
CPP src/array.c -> build/host/src/array.pi
In file included from /var/tmp/mruby/src/array.c:7:
In file included from /var/tmp/mruby/include/mruby.h:115:
In file included from /var/tmp/mruby/include/mruby/value.h:203:
/var/tmp/mruby/include/mruby/boxing_word.h:11:10: warning:
'MRB_WORDBOX_NO_FLOAT_TRUNCATE' macro redefined [-Wmacro-redefined]
# define MRB_WORDBOX_NO_FLOAT_TRUNCATE
^
<command line>:3:9: note: previous definition is here
#define MRB_WORDBOX_NO_FLOAT_TRUNCATE 1
^
1 warning generated.
...SNIP...
```
mimaki