mattn / mruby-onig-regexp

mrbgem of 鬼雲's Regular Expression

mruby-onig-regexp

install by mrbgems

MRuby::Build.new do |conf|

    # ... (snip) ...

    conf.gem :github => 'mattn/mruby-onig-regexp'
end

Example

def matchstr(str)
  reg = Regexp.compile("abc")

  if reg =~ str then
    p "match"
  else
    p "not match"
  end
end

matchstr("abcdef") # => match
matchstr("ghijkl") # => not match
matchstr("xyzabc") # => match

License

MIT

License of Onigmo

BSD licensed.

Onigmo (Oniguruma-mod)  --  (C) K.Takata <kentkt AT csc DOT jp>
Oniguruma  ----   (C) K.Kosako <sndgk393 AT ybb DOT ne DOT jp>

Author

Yasuhiro Matsumoto (a.k.a mattn)

mruby-onig-regexp's Issues

build with bundled onigmo fails when c++ API is enabled

When I put conf.enable_cxx_api into my build_config.rb, building mruby-onig-regexp fails because it tries to build onigmo with a C++ compiler, but onigmo can not be built with a C++ compiler (e.g., it uses not as a field name in a struct, but that is a keyword in C++).

I see two ways to fix this: (1) build this mrbgem with CC even if the C++ API is enabled or (2) try to change Onigmo to build with a C++ compiler.

Doesn't freak out when replacing `^`

$cat t.rb
"Text\nFoo".gsub(/^/, ' ')

$ ruby t.rb
" Text\n Foo"

$ mruby t.rb
" Text\n ext\n xt\n t\n \n Foo"

See also https://github.com/ruby/spec/blob/0fe99d24f4a17eaa39563623209747eee278c3d1/core/string/gsub_spec.rb#L38

Segmentation fault: 11 on mirb

[koji@macbookpro:~/work/mruby/mruby]$ mirb
mirb - Embeddable Interactive Ruby Shell

This is a very early version, please test and report errors.
Thanks :)

> Regexp
 => OnigRegexp
> "foobar" =~ /bar/
Segmentation fault: 11

I'm using Mac OSX Moutain Lion(10.8), clang is,

[koji@macbookpro:~/work/mruby/mruby]$ clang --version
Apple LLVM version 4.2 (clang-425.0.28) (based on LLVM 3.2svn)
Target: x86_64-apple-darwin12.4.0
Thread model: posix

/./ should match to latin-1 letter when MRB_UTF8_STRING is not defined.

See #64

Freeze regex variable

Is there a way to free regex in variable that should not be change through out lifetime? It appear I couldn't get the match working.

Working:

/^[A]{1}[0-9]{6}[A-Z]{1}$/.match?("A123456A".freeze) ? "" : res << {"IC" => "err1"}

Wanted:

ic = Regex.new("/^[A]{1}[0-9]{6}[A-Z]{1}$").freeze

No way to explicitly use the included libonig instead of what is installed on the host system

My build machine has libonig installed for reasons unrelated to mruby. When I build my project, it links against that version instead of the one that comes with the gem. Since the installed libonig is a shared library and the project is intended to produce a distributable binary, this is a problem.

I would like a way to force the gem to always use its own version of the library even if there's a version present on the system.

I've coded the change and will submit a pull request.

Example given in README segfaults

On a clean mruby build from #958d5b7, with mruby-onig-regexp as the only gem added to default gemset, executing the sample code given in readme gives a segfault.
Working on OS X 10.8.4 with latest devtools.
Am I the only one?

Problems finding oniguruma.h

Every since #52, I've been having problems building this library in my mruby-cli project. It can't seem to find "oniguruma.h". I'm using mruby 1.2.0. Reverting to the previous commit fixes it for me.

CC    build/mrbgems/mruby-onig-regexp/src/mruby_onig_regexp.c -> build/host/mrbgems/mruby-onig-regexp/src/mruby_onig_regexp.o
/home/mruby/code/mruby/build/mrbgems/mruby-onig-regexp/src/mruby_onig_regexp.c:44:23: fatal error: oniguruma.h: No such file or directory
 #include "oniguruma.h"

Can not cross complie for x86_64-w64-mingw32 on Mac

I used 'mingw-w64-x86_64-onigmo-6.2.0-1-any.pkg.tar '.
An error on the way.

./libtool: line 1727: lib: command not found
make[2]: *** [libonigmo.la] Error 127
make[1]: *** [all-recursive] Error 1
make: *** [all] Error 2
rake aborted!
make -j1 failed
./mruby/build/mrbgems/mruby-onig-regexp/mrbgem.rake:47:in `run_command'
./mruby/build/mrbgems/mruby-onig-regexp/mrbgem.rake:70:in `block (2 levels) in bundle_onigmo'
./mruby/build/mrbgems/mruby-onig-regexp/mrbgem.rake:56:in `chdir'
./mruby/build/mrbgems/mruby-onig-regexp/mrbgem.rake:56:in `block in bundle_onigmo'

Here is my environment.

Hardware Overview:

Model Name: Mac mini
Model Identifier: Macmini8,1
Processor Name: 6-Core Intel Core i7
Processor Speed: 3.2 GHz
Number of Processors: 1
Total Number of Cores: 6
L2 Cache (per Core): 256 KB
L3 Cache: 12 MB
Hyper-Threading Technology: Enabled
Memory: 64 GB
System Firmware Version: 1715.60.5.0.0 (iBridge: 19.16.10647.0.0,0)
OS Loader Version: 540.60.2~89

clang -v
Apple clang version 13.0.0 (clang-1300.0.29.30)
Target: x86_64-apple-darwin21.2.0
Thread model: posix

Interl MacでWindows64bit用のコンパイルができませんでした。

Trouble splitting string with Regexp

Hi,

I'm having some issues splitting strings with Regexps in mruby-onig-regexp

The following:

"<%= 1 + 1 %>".split(/(<%=)|(%>)/)

doesn't split and returns ["<%= 1 + 1 %>"]. The same expression splits fine in MRI. I checked that mruby-onig-regexp substitutes String#split with a Regexp-aware implementation, so either I'm doing something seriously wrong or maybe there's a bug in mruby-onig-regexp

thanks,
Ricardo

Conflicting symbols from oniguruma and libc cause segfault / bad memory writes

Hi.

I'm not very familiar with oniguruma, so please excuse any possible misunderstandings.

Your gem always causes segfaults/aborts for me (even the example) in mruby's gc heap cleanup. Valgrind reports multiple invalid writes in "regcomp" and "regexec". From what I have seen, oniguruma defines the type regex_t and the above functions, but those same types/symbols are also defined in the posix header "regex.h", and when I trace my program, I see that indeed at eg. "regcomp" the CPU does not jump into libonig but into libc.

Now, I'm sure that the regex_t type defined in the posix header is bigger than the one in "onigposix.h", so what I think happens is that the gem allocates a too small regex_t and regcomp/regexec defined in libc access and write to unallocated memory.

This is how regex_t looks in onigposix.h:

typedef struct {
  void*   onig;          /* Oniguruma regex_t*  */
  size_t  re_nsub;
  int     comp_options;
} regex_t;

And this is how it looks in the posix header regex.h:

struct re_pattern_buffer
{
  unsigned char *__REPB_PREFIX(buffer);
  unsigned long int __REPB_PREFIX(allocated);
  unsigned long int __REPB_PREFIX(used);
  reg_syntax_t __REPB_PREFIX(syntax);
  char *__REPB_PREFIX(fastmap);
  size_t re_nsub;
  unsigned __REPB_PREFIX(can_be_null) : 1;
  unsigned __REPB_PREFIX(regs_allocated) : 2;
  unsigned __REPB_PREFIX(fastmap_accurate) : 1;
  unsigned __REPB_PREFIX(no_sub) : 1;
  unsigned __REPB_PREFIX(not_bol) : 1;
  unsigned __REPB_PREFIX(not_eol) : 1;
  unsigned __REPB_PREFIX(newline_anchor) : 1;
};
typedef struct re_pattern_buffer regex_t;

I am using oniguruma 5.9.4

Edit: I just tried it out. In onig_regexp_init:

reg = malloc(sizeof(struct mrb_onig_regexp));

this allocates 32 bytes.

But if I test sizeof(regex_t) with "regex.h" posix header, I get 64 bytes size.

(I am on a 64 bit Linux system btw.)

MatchData with range

Would it be possible to support ranges?

For example, in URI we can split the parts with destructuring assignment:

scheme, host, port, path, query = $~[1..-1]

However, this will result in invalid MatchData index type: 1..-1 in mruby.

How to cross compile this gem?

I'm trying to cross compile this gem. Unfortunately, it's not success. Do you have some steps to do that? Thanks

onigposix.h missing

Hi @mattn,

I'm getting at the moment the following error while building:

build/mrbgems/mruby-onig-regexp/src/mruby_orig_regexp.c:10:23: fatal error: onigposix.h: No such file or directory

Does it maybe make sense to integrate oniguruma directly into the GEM? What is your plan about that?

Regards
Daniel

Slice on empty string

"".slice(/^.*$/) 

In ruby this returns empty string (""), but in mruby nil is returned.

Abort on UTF-8 split with empty src

Enable MRB_UTF8_STRING on mrbconf.h

"あいうえお".split("")
#=> ["あ", "い", "う", "え", "お"]

"あいうえお".onig_regexp_split(OnigRegexp.new(""))
#=> Assertion failed: (((((const mrb_value*)((struct RArray*)((result).value.p))->ptr)[i - 1]).tt == MRB_TT_STRING)), function string_split, file /Users/ksss/src/github.com/ksss/mruby-onig-regexp/src/mruby_onig_regexp.c, line 857.
# Expect => ["あ", "い", "う", "え", "お"]

Supporting non-word char in group name

ref #90

I want to discuss about group name.

Current

mruby-onig-regexp can use non-word char in group name when linked by oniguruma.
But it can't use when linked by onigmo.

link with	oniguruma.so	onigmo.so	bundled onigmo
non-word	OK	NG	NG

Problem

So, mgem can't use non-word char in group name because it depends on mruby-onig-regexp. (e.g. mruby-uri)

Background

CRuby can use non-word char in group name.

$ ruby -e 'p Regexp.new("bad(?<aa-bb>.*)").match("badboy")["aa-bb"]'
"boy"

I investigated the background.

• oniguruma allows non-word char (like '-') in group name.
• onigmo does not allows non-word char in group name.
• CRuby change regexp library from oniguruma to onigmo. However, It kept backward compatibility by patching onigmo.

Discussion point

I think, we have some solutions.

• No change. We allow incompatibility by linked library.
• Add compile option to onigmo like ONIG_OPTION_ALLOW_NON_WORD_CHAR_IN_CAPTURE_GROUP.
• Drop supporting linking with shared library and use bundled onigmo only.
• Fork mruby-onig-regexp and it support only bundled onigmo only.
• Add patch to bundled onigmo in mruby-onig-regexp like this. But this solution can't resolve when linking with existing onigmo.so

diff --git a/mrbgem.rake b/mrbgem.rake
index 0d37b12..1404353 100644
--- a/mrbgem.rake
+++ b/mrbgem.rake
@@ -66,6 +66,7 @@ MRuby::Gem::Specification.new('mruby-onig-regexp') do |spec|
           _pp 'autotools', oniguruma_dir
           run_command e, './autogen.sh' if File.exists? 'autogen.sh'
           run_command e, "./configure --disable-shared --enable-static #{host}"
+          run_command e, "patch -p1 < #{dir}/onigmo-#{version}.patch"
           run_command e, "make -j#{$rake_jobs || 1}"
         else
           run_command e, 'cmd /c "copy /Y win32 > NUL"'
diff --git a/onigmo-6.1.3.patch b/onigmo-6.1.3.patch
new file mode 100644
index 0000000..4163913
--- /dev/null
+++ b/onigmo-6.1.3.patch
@@ -0,0 +1,13 @@
+diff --git a/regparse.c b/regparse.c
+index 431aad9..54563ac 100644
+--- a/regparse.c
++++ b/regparse.c
+@@ -2509,7 +2509,7 @@ get_name_end_code_point(OnigCodePoint start)
+ # ifdef RUBY
+ #  define ONIGENC_IS_CODE_NAME(enc, c)  TRUE
+ # else
+-#  define ONIGENC_IS_CODE_NAME(enc, c)  ONIGENC_IS_CODE_WORD(enc, c)
++#  define ONIGENC_IS_CODE_NAME(enc, c)  TRUE
+ # endif
+
+ # ifdef USE_BACKREF_WITH_LEVEL

I think mruby's regexp should support non-word char in group name.
Because I think it is better that the specification of mruby as close as possible to CRuby.
But I have to fork mruby-onig-regexp to resolve the problem perfectly.

How do you think?

rake all test failed

Hi, @mattn

rake all test was failed with mruby

Please see travis test.

https://travis-ci.org/matsumoto-r/mrbgem_test_ci/builds/22588120#L2034-L2040

Fail: $1 to $9
 - Assertion[1] Failed: Expected to be equal
    Expected: "aaab"
      Actual: nil
 - Assertion[2] Failed: Expected to be equal
    Expected: "b"
      Actual: nil

ld: symbol(s) not found for architecture x86_64

How can I integrate this mrbgem to run in IOS and Android device? I can compiled all code without errors. But when I execute the code for test on my Macbook, the error "ld: symbol(s) not found for architecture x86_64" occurs. Thanks!!

Segmentation fault: 11 on mirb

[koji@macbookpro:~/work/mruby/mruby]$ mirb
mirb - Embeddable Interactive Ruby Shell

This is a very early version, please test and report errors.
Thanks :)

> Regexp
 => OnigRegexp
> "foobar" =~ /bar/
Segmentation fault: 11

I'm using Mac OSX Moutain Lion(10.8), clang is,

[koji@macbookpro:~/work/mruby/mruby]$ clang --version
Apple LLVM version 4.2 (clang-425.0.28) (based on LLVM 3.2svn)
Target: x86_64-apple-darwin12.4.0
Thread model: posix

Second argument of Regexp#initialize.

According to ISO spec, if second argument of Regexp#initialize is other than Integer, nil and false, flag should be REG_ICASE.
Therefore, Regexp.new("abc", "im") should be equal to Regexp.new("abc", Regexp::IGNORECASE)
not to Regexp.new("abc", Regexp::IGNORECASE | Regexp::MULTILINE).

CRuby's Example

a = Regexp.new("ab.*END", "im")
p a.match("ab end\n end")[0]
  # => "ab end"  ('.' does not match "\n").

Support `Regexp#match?`

mruby/mruby#3968

Match? bug

Just discovered a bug when used in comparing against regex?

Did not match, should be match
if /jpg/.match?(env["HTTP_ACCEPT"])

Working, match as expected
if /jpg/.match(env["HTTP_ACCEPT"])

string size too big (ArgumentError)

I found a bug (strange error raised):

$ ./bin/mruby -e 'p "\xf0".gsub(/[^a]/,"X")'
trace:
    [0] -e:1
-e:1: string size too big (ArgumentError)

When using onig_regexp_gsub and OnigRegexp#new, same error is raised.

$ ./bin/mruby -e 'p "\xf0".onig_regexp_gsub(OnigRegexp.new("[^a]"),"X")'
trace:
    [0] -e:1
-e:1: string size too big (ArgumentError)

mruby Regexp check with onig

Some method in mruby, like String#slice should be able to use OnigRegexp. For example,

# in MRI
>> "123hello456".slice(/[a-z]+/) #=> "hello"

# in mruby
> "123hello456".slice(/[a-z]+/)
(mirb):1: Regexp class not implemented (NotImplementedError)

> "123hello456".slice(OnigRegexp.new("/[a-z]+/"))
(mirb):2: Regexp class not implemented (NotImplementedError)

It seems they are using mrb_regexp_check.

Any ideas?

Compilation failed on Visual Studio 2019

Summary

Compiling using Visual Studio 16.0, throws the following unresolved external symbols:

libmruby.lib(mruby_onig_regexp.obj) : error LNK2019: unresolved external symbol onig_free referenced in function onig_regexp_free
libmruby.lib(mruby_onig_regexp.obj) : error LNK2019: unresolved external symbol onig_search referenced in function onig_match_common
libmruby.lib(mruby_onig_regexp.obj) : error LNK2019: unresolved external symbol onig_region_new referenced in function create_onig_region
libmruby.lib(mruby_onig_regexp.obj) : error LNK2019: unresolved external symbol onig_region_free referenced in function match_data_free
libmruby.lib(mruby_onig_regexp.obj) : error LNK2019: unresolved external symbol onig_region_copy referenced in function match_data_copy
libmruby.lib(mruby_onig_regexp.obj) : error LNK2019: unresolved external symbol onig_name_to_backref_number referenced in function append_replace_str
libmruby.lib(mruby_onig_regexp.obj) : error LNK2019: unresolved external symbol onig_get_encoding referenced in function onig_regexp_inspect
libmruby.lib(mruby_onig_regexp.obj) : error LNK2019: unresolved external symbol onig_get_options referenced in function onig_regexp_casefold_p
libmruby.lib(mruby_onig_regexp.obj) : error LNK2019: unresolved external symbol onig_version referenced in function onig_regexp_version
libmruby.lib(mruby_onig_regexp.obj) : error LNK2001: unresolved external symbol OnigEncodingASCII
libmruby.lib(mruby_onig_regexp.obj) : error LNK2001: unresolved external symbol OnigEncodingUTF_8
libmruby.lib(mruby_onig_regexp.obj) : error LNK2001: unresolved external symbol OnigSyntaxRuby
libmruby.lib(mruby_onig_regexp.obj) : error LNK2001: unresolved external symbol OnigDefaultSyntax
mrbtest.exe : fatal error LNK1120: 15 unresolved externals
libmruby.lib(mruby_onig_regexp.obj) : error LNK2019: unresolved external symbol onig_error_code_to_str referenced in function onig_match_common
libmruby.lib(mruby_onig_regexp.obj) : error LNK2019: unresolved external symbol onig_new referenced in function onig_regexp_initialize
libmruby.lib(mruby_onig_regexp.obj) : error LNK2019: unresolved external symbol onig_free referenced in function onig_regexp_free
libmruby.lib(mruby_onig_regexp.obj) : error LNK2019: unresolved external symbol onig_search referenced in function onig_match_common
libmruby.lib(mruby_onig_regexp.obj) : error LNK2019: unresolved external symbol onig_region_new referenced in function create_onig_region
libmruby.lib(mruby_onig_regexp.obj) : error LNK2019: unresolved external symbol onig_region_free referenced in function match_data_free
libmruby.lib(mruby_onig_regexp.obj) : error LNK2019: unresolved external symbol onig_region_copy referenced in function match_data_copy
libmruby.lib(mruby_onig_regexp.obj) : error LNK2019: unresolved external symbol onig_name_to_backref_number referenced in function append_replace_str
libmruby.lib(mruby_onig_regexp.obj) : error LNK2019: unresolved external symbol onig_get_encoding referenced in function onig_regexp_inspect
libmruby.lib(mruby_onig_regexp.obj) : error LNK2019: unresolved external symbol onig_get_options referenced in function onig_regexp_casefold_p
libmruby.lib(mruby_onig_regexp.obj) : error LNK2019: unresolved external symbol onig_version referenced in function onig_regexp_version
libmruby.lib(mruby_onig_regexp.obj) : error LNK2001: unresolved external symbol OnigEncodingASCII
libmruby.lib(mruby_onig_regexp.obj) : error LNK2001: unresolved external symbol OnigEncodingUTF_8
libmruby.lib(mruby_onig_regexp.obj) : error LNK2001: unresolved external symbol OnigSyntaxRuby
libmruby.lib(mruby_onig_regexp.obj) : error LNK2001: unresolved external symbol OnigDefaultSyntax

Environment

Visual studio version: 16 (VS 2019)
Arch: x86_64
Mruby version: 2.1.2
Build config:

MRuby::Build.new do |conf|
  if ENV['VisualStudioVersion'] || ENV['VSINSTALLDIR']
    conf.toolchain :visualcpp
  else
    conf.toolchain :gcc
  end

  conf.gembox 'default'
  conf.gem github: 'mattn/mruby-onig-regexp'

  conf.enable_test

  if ENV['DEBUG'] == 'true'
    conf.enable_debug
    conf.cc.defines = %w[MRB_ENABLE_DEBUG_HOOK]
    conf.gem core: 'mruby-bin-debugger'
  end

slice! does not work with Regexp

メールにて不具合報告

■ テストコード

'abc'.slice!(/./m)

■ エラー内容 (mruby 1.4.0)

trace (most recent call last):
        [0] test.rb:1
        [1] c:\mruby\mrbgems\mruby-string-ext\mrblib\string.rb:207:in slice!
c:\mruby\mrbgems\mruby-string-ext\mrblib\string.rb:207: undefined method '<' (NoMethodError)

■ 呼び出し元 onig_regexp.rb

  def slice!(*args)
    if args.size < 2
      result = slice(*args)    ### ←この先でエラー

■ 該当コード string.rb (mruby 1.4.0)

def slice!(arg1, arg2=nil)
    raise FrozenError, "can't modify frozen String" if frozen?
    raise "wrong number of arguments (for 1..2)" if arg1.nil? && arg2.nil?

    if !arg1.nil? && !arg2.nil?
      idx = arg1
      idx += self.size if arg1 < 0   #### ←ここでエラー

■ 該当コード string.rb (mruby 2.0.1)

def slice!(arg1, arg2=nil)
  (中略)
  if arg1.kind_of?(Range)
  (略)
  elsif arg1.kind_of?(String)
        validated = true
  else
    idx = arg1
    idx += self.size if arg1 < 0   #### ←ここでエラー

mrubyもrubyも最近始めたばかりで、私はド素人なのですが
本家のString.slice!がarg1を文字列か数値でしか判断していないので、
arg1がRegexpだった場合、それを呼ばずに別の処理が必要ではないでしょうか。

gem description maybe is "鬼車", not "鬼雲" ?

oniguruma name
https://github.com/kkos/oniguruma/blob/master/README.ja

test fails when MRB_UTF8_STRING is defined

Segmentation fault occurs in the following test when MRB_UTF8_STRING is defined.

assert_raise(ArgumentError) { "\xf0".gsub(/[^a]/,"X") }

(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x107ffffe0)
  * frame #0: 0x000000019a034328 libsystem_platform.dylib`_platform_memmove + 536
    frame #1: 0x0000000100044ac8 mrbtest`str_init_embed(s=0x00000001200080f0, p="", len=-3) at string.c:53:10
    frame #2: 0x0000000100044d68 mrbtest`str_new(mrb=0x0000000102008200, p="", len=-3) at string.c:121:12
    frame #3: 0x0000000100044d0c mrbtest`mrb_str_new(mrb=0x0000000102008200, p="", len=-3) at string.c:160:24
    frame #4: 0x00000001000938c8 mrbtest`str_substr(mrb=0x0000000102008200, str=(w = 4831871456), beg=4, len=-3) at mruby_onig_regexp.c:105:10
    frame #5: 0x000000010008ff7c mrbtest`match_data_post_match(mrb=0x0000000102008200, self=(w = 4831871936)) at mruby_onig_regexp.c:646:10
    frame #6: 0x000000010005510c mrbtest`mrb_funcall_with_block(mrb=0x0000000102008200, self=(w = 4831871936), mid=1118, argc=0, argv=0x000000016fdfd958, blk=(w = 0)) at vm.c:561:13
    frame #7: 0x00000001000549c4 mrbtest`mrb_funcall_argv(mrb=0x0000000102008200, self=(w = 4831871936), mid=1118, argc=0, argv=0x000000016fdfd958) at vm.c:577:10
    frame #8: 0x0000000100054924 mrbtest`mrb_funcall(mrb=0x0000000102008200, self=(w = 4831871936), name="post_match", argc=0) at vm.c:374:10
    frame #9: 0x0000000100092f38 mrbtest`onig_match_common(mrb=0x0000000102008200, reg=0x000000010180a7e0, match_value=(w = 4831871936), str=(w = 4831873760), pos=0) at mruby_onig_regexp.c:199:16
    frame #10: 0x000000010009056c mrbtest`string_gsub(mrb=0x0000000102008200, self=(w = 4831873760)) at mruby_onig_regexp.c:794:8
    frame #11: 0x00000001000594f8 mrbtest`mrb_vm_exec(mrb=0x0000000102008200, proc=0x0000000120008b40, pc="8\U00000002") at vm.c:1636:18
    frame #12: 0x0000000100056cf8 mrbtest`mrb_vm_run(mrb=0x0000000102008200, proc=0x000000012000fa10, self=(w = 4831919648), stack_keep=0) at vm.c:1131:12
    frame #13: 0x0000000100055d30 mrbtest`mrb_top_run(mrb=0x0000000102008200, proc=0x000000012000fa10, self=(w = 4831919648), stack_keep=0) at vm.c:3040:12
    frame #14: 0x0000000100037310 mrbtest`load_irep(mrb=0x0000000102008200, proc=0x000000012000fa10, c=0x0000000000000000) at load.c:681:10
    frame #15: 0x0000000100037224 mrbtest`mrb_load_irep_cxt(mrb=0x0000000102008200, bin="RITE0300", c=0x0000000000000000) at load.c:689:10
    frame #16: 0x00000001000373a0 mrbtest`mrb_load_irep(mrb=0x0000000102008200, bin="RITE0300") at load.c:701:10
    frame #17: 0x00000001000058a0 mrbtest`GENERATED_TMP_mrb_mruby_enum_ext_gem_test(mrb=0x0000000100809800) at gem_test.c:588:3
    frame #18: 0x0000000100004ef8 mrbtest`mrbgemtest_init(mrb=0x0000000100809800) at mrbtest.c:54:5
    frame #19: 0x0000000100003d40 mrbtest`main(argc=1, argv=0x000000016fdff718) at driver.c:304:3
    frame #20: 0x00000001002b10f4 dyld`start + 520

infinite loop when empty regexp

"hello".gsub(//, ".")
# Expect => ".h.e.l.l.o."
# Actual => infinite loop

See also https://github.com/ruby/spec/blob/0fe99d24f4a17eaa39563623209747eee278c3d1/core/string/gsub_spec.rb#L25

https://github.com/ruby/ruby/blob/745f4dd5b834a00f1cc201adb72ea3c8c8d4decb/string.c#L5005-L5006