GCC emits a lot of false positives for rb_scan_args because:
* `rb_scan_args(argc, argv, "*:", NULL, &opts);` makes `n_mand == 0`,
* `n_mand == argc + 1` implies `argc == -1`, and
* `memcpy(ptr, argv, sizeof(VALUE)*argc);` explodes
However, we know that argc is never so big, thus this is a false
positive. This change suppresses it by adding a condition `n_mand > 0`.
```
In file included from /usr/include/string.h:494,
from ./include/ruby/defines.h:145,
from ./include/ruby/ruby.h:29,
from ./include/ruby/encoding.h:27,
from dir.c:14:
In function 'memcpy',
inlined from 'ruby_nonempty_memcpy.part.0' at ./include/ruby/ruby.h:1763:17,
inlined from 'ruby_nonempty_memcpy' at ./include/ruby/ruby.h:1760:1,
inlined from 'rb_scan_args_set' at ./include/ruby/ruby.h:2594:9,
inlined from 'dir_s_aref' at dir.c:2774:12:
/usr/include/x86_64-linux-gnu/bits/string_fortified.h:34:10: warning: '__builtin___memcpy_chk' pointer overflow between offset 0 and size [-8, 9223372036854775807] [-Warray-bounds]
return __builtin___memcpy_chk (__dest, __src, __len, __bos0 (__dest));
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/x86_64-linux-gnu/bits/string_fortified.h:34:10: warning:
'__builtin___memcpy_chk' specified size 18446744073709551608 exceeds maximum object size 9223372036854775807 [-Wstringop-overflow=]
```
This approach uses a flag bit on the final hash object in the regular splat,
as opposed to a previous approach that used a VM frame flag. The hash flag
approach is less invasive, and handles some cases that the VM frame flag
approach does not, such as saving the argument splat array and splatting it
later:
ruby2_keywords def foo(*args)
@args = args
bar
end
def bar
baz(*@args)
end
def baz(*args, **kw)
[args, kw]
end
foo(a:1) #=> [[], {a: 1}]
foo({a: 1}, **{}) #=> [[{a: 1}], {}]
foo({a: 1}) #=> 2.7: [[], {a: 1}] # and warning
foo({a: 1}) #=> 3.0: [[{a: 1}], {}]
It doesn't handle some cases that the VM frame flag handles, such as when
the final hash object is replaced using Hash#merge, but those cases are
probably less common and are unlikely to properly support keyword
argument separation.
Use ruby2_keywords to handle argument delegation in the delegate library.
Cfuncs that use rb_scan_args with the : entry suffer similar keyword
argument separation issues that Ruby methods suffer if the cfuncs
accept optional or variable arguments.
This makes the following changes to : handling.
* Treats as **kw, prompting keyword argument separation warnings
if called with a positional hash.
* Do not look for an option hash if empty keywords are provided.
For backwards compatibility, treat an empty keyword splat as a empty
mandatory positional hash argument, but emit a a warning, as this
behavior will be removed in Ruby 3. The argument number check
needs to be moved lower so it can correctly handle an empty
positional argument being added.
* If the last argument is nil and it is necessary to treat it as an option
hash in order to make sure all arguments are processed, continue to
treat the last argument as the option hash. Emit a warning in this case,
as this behavior will be removed in Ruby 3.
* If splitting the keyword hash into two hashes, issue a warning, as we
will not be splitting hashes in Ruby 3.
* If the keyword argument is required to fill a mandatory positional
argument, continue to do so, but emit a warning as this behavior will
be going away in Ruby 3.
* If keyword arguments are provided and the last argument is not a hash,
that indicates something wrong. This can happen if a cfunc is calling
rb_scan_args multiple times, and providing arguments that were not
passed to it from Ruby. Callers need to switch to the new
rb_scan_args_kw function, which allows passing of whether keywords
were provided.
This commit fixes all warnings caused by the changes above.
It switches some function calls to *_kw versions with appropriate
kw_splat flags. If delegating arguments, RB_PASS_CALLED_KEYWORDS
is used. If creating new arguments, RB_PASS_KEYWORDS is used if
the last argument is a hash to be treated as keywords.
In open_key_args in io.c, use rb_scan_args_kw.
In this case, the arguments provided come from another C
function, not Ruby. The last argument may or may not be a hash,
so we can't set keyword argument mode. However, if it is a
hash, we don't want to warn when treating it as keywords.
In Ruby files, make sure to appropriately use keyword splats
or literal keywords when calling Cfuncs that now issue keyword
argument separation warnings through rb_scan_args. Also, make
sure not to pass nil in place of an option hash.
Work around Kernel#warn warnings due to problems in the Rubygems
override of the method. There is an open pull request to fix
these issues in Rubygems, but part of the Rubygems tests for
their override fail on ruby-head due to rb_scan_args not
recognizing empty keyword splats, which this commit fixes.
Implementation wise, adding rb_scan_args_kw is kind of a pain,
because rb_scan_args takes a variable number of arguments.
In order to not duplicate all the code, the function internals need
to be split into two functions taking a va_list, and to avoid passing
in a ton of arguments, a single struct argument is used to handle
the variables previously local to the function.
It says:
vm.c:2519:34: warning: expression does not compute the number of elements in this array; element type is 'const struct __jmp_buf_tag', not 'VALUE' (aka 'unsigned long') [-Wsizeof-array-div]
sizeof(ec->machine.regs) / sizeof(VALUE));
~~~~~~~~~~~~~~~~ ^
vm.c:2519:34: note: place parentheses around the 'sizeof(VALUE)' expression to silence this warning
The original st.c was public domain hash table implementation, but
Ruby's st.c is highly modified, and its data structure is not
compatiblie with the original one.
Therefore, when creating an extension library to wrap C code that uses
the original st.c, the symbols conflict, which leads to segfault.
This changes the prefix `st_*` of st.c functions to `rb_st_*` for
reflecting that they are specific to Ruby's, and avoid symbol conflicts.
This function was created as a variant of st_copy with firing write
barrier.
It should have more explicit name, such as st_copy_with_write_barrier.
But because it is used only for copying iv_tbl, so I rename it to
rb_iv_tbl_copy now. If we face other use case than iv_tbl, we may want
to rename it to more general name.
`check-snapshot-ruby_2_4` uses `make test` instead of `make check`.
95692e54f4/.github/workflows/snapshot.yml (L448-L449)
`draft-release` use `make check` to make it simple, and
actions is required regardless of success or failure.
On the other hand, snapshot success can be ignored,
so normally it should not fail.
This is how Kernel#{Array,String,Float,Integer,Hash,Rational} work.
BigDecimal and Complex instances are always frozen, so this should
not cause backwards compatibility issues for those. Pathname
instances are not frozen, so potentially this could cause backwards
compatibility issues by not returning a new object.
Based on a patch from Joshua Ballanco, some minor changes by me.
Fixes [Bug #7522]
Yusuke Endoh
Nobuyoshi Nakada
Jeremy Evans
git
Koichi Sasada
Kazuhiro NISHIYAMA
卜部昌平
aycabta
Lourens Naudé