This commit renames rb_str_tmp_frozen_no_embed_acquire to rb_str_no_gvl_safe_acquire
and makes it part of the public C API.
There is currently no way for C extensions that use no GVL operations to
safely read from a string because it has no way of guaranteeing that the
string is not embedded. Embedded strings are not safe for no GVL operations
because GC compaction can run, which will mprotect the memory region and
will cause any read to SEGV.
See https://github.com/ruby/ruby/pull/9817 for when rb_str_tmp_frozen_no_embed_acquire
was introduced.
capa does not include the terminator, so when a buffer moves
between strings with different terminator lengths the capacity has to
be converted or we will try to free the buffer with the wrong size:
[BUG] buffer 0x00005030039ff768 freed with old_size=18, but was allocated with size=17
[BUG] buffer 0x00005631adc48f48 freed with old_size=8268, but was allocated with size=8269
Three related fixes:
* `rb_str_tmp_frozen_release`: convert tmp's capacity to orig's
terminator length when handing the buffer back. This is the inverse
of a calculation added to `rb_str_tmp_frozen_no_embed_acquire` in
91619f0230.
* `heap_str_make_shared`: since bdf3032e35
the root created by `rb_str_tmp_frozen_acquire` does not copy the
encoding of the string it takes the buffer from, so the two can have
different terminator lengths and the root's capacity has to be
adjusted as well, otherwise the root frees fewer bytes than were
allocated once its only child stops sharing the buffer. termlen is
passed in because the caller assigns the encoding of the root after
this function returns.
* `rb_str_tmp_frozen_no_embed_acquire`: unset `STR_BORROWED` on the
root. `STR_SET_SHARED` sets `STR_BORROWED` on roots with
`klass == 0` to mark the ones that may have other children, but this
root only ever has orig as its child, so unset it like
`heap_str_make_shared` does. Any string that starts sharing the
root later will set the flag again. Without this
`rb_str_tmp_frozen_release` never gives the buffer back, so strings
written by `io_fwrite` stay shared and are copied on their next
modification.
The release and make_shared adjustments go together
as they were previously canceling each other out.
45a2c95d0f mistakenly rewrote
FL_TEST_RAW(orig, STR_SHARED) && !FL_TEST_RAW(orig, STR_TMPLOCK|RUBY_FL_FREEZE)
as
FL_TEST_RAW(orig, STR_SHARED | STR_TMPLOCK) == STR_TMPLOCK
requiring orig to not be shared, the opposite of the original
condition. orig always shares the buffer with tmp here, so the buffer
was never given back and the string stayed shared until its next
modification copied it. The code then read aux.shared from strings
that are not shared, where the union holds aux.capa.
This should be backported to 4.0
Replace `tool/update-deps` with a Ruby source scanner so dependency
updates no longer require GNU make, a configured build, or compiler
preprocessor output.
Keep compact source mappings and scanner declarations in dependency
files, and expand complete rules into the build directory. Avoid the
temporary fixture headers required by the compiler-driven prototype.
Use the generated rules from GNU make, BSD make, and NMake builds.
Support out-of-tree and read-only source trees, and retain expanded
dependencies shipped in release archives when baseruby is unavailable.
Followup: https://github.com/ruby/ruby/pull/17671
[Bug #22184]
`onigmo.h` contains a lot of declarations that can easily
conflict with third party code, hence it's better to keep
it opaque. That however requires a few hacks.
When embeddeding `struct re_pattern_buffer`, `RRegexp` end up
488B large, which result in a rather minimal 24B waste in 512B slots.
This however requires a few changes:
- Stop relying on `RREGEXP_PTR == NULL` to check for initialization.
- `reg_copy` requires a new `onig_reg_copy_body` API.
For now the provided size is just for GC statistics, but in the future
we may want to forward it to C23's `free_sized` and passing an incorrect
size to it is undefined behavior.
`File.join` is a hotspot for common libraries such as Zeitwerk
and Bootsnap. It has a fairly flexible signature, but 99% of
the time it's called with just two (or a small number of) UTF-8 strings.
If we optimistically optimize for that use case we can cut down a large
number of type and encoding checks, significantly speeding up the method.
The one remaining expensive check we could try to optimize is `str_null_check`.
Given it's common to use the same base string for joining, we could memoize it.
Also we could precompute it for literal strings.
```
compare-ruby: ruby 4.1.0dev (2026-01-17T14:40:03Z master 00a3b71eaf) +PRISM [arm64-darwin25]
built-ruby: ruby 4.1.0dev (2026-01-18T12:10:38Z spedup-file-join 069bab58d4) +PRISM [arm64-darwin25]
warming up....
| |compare-ruby|built-ruby|
|:-------------|-----------:|---------:|
|two_strings | 2.475M| 9.444M|
| | -| 3.82x|
|many_strings | 551.975k| 2.346M|
| | -| 4.25x|
|array | 514.946k| 522.034k|
| | -| 1.01x|
|mixed | 621.236k| 633.189k|
| | -| 1.02x|
```
[Feature #20205]
Now that chilled strings no longer appear as frozen, there is no
need to offer an API to check for chilled strings.
We however need to change `rb_check_frozen_internal` to no
longer be a macro, as it needs to check for chilled strings.
Some extensions (like stringio) may need to differentiate between
chilled strings and frozen strings.
They can now use rb_str_chilled_p but must check for its presence since
the function will be removed when chilled strings are removed.
[Bug #20389]
[Feature #20205]
Co-authored-by: Jean Boussier <byroot@ruby-lang.org>
The documentation for `rb_enc_interned_str_cstr` notes that `enc` can be
a null pointer, but this currently causes a segmentation fault when
trying to autoload the encoding. This commit fixes the issue by checking
for NULL before calling `rb_enc_autoload`.
* Unify length field for embedded and heap strings
The length field is of the same type and position in RString for both
embedded and heap allocated strings, so we can unify it.
* Remove RSTRING_EMBED_LEN
Remove !USE_RVARGC code
[Feature #19579]
The Variable Width Allocation feature was turned on by default in Ruby
3.2. Since then, we haven't received bug reports or backports to the
non-Variable Width Allocation code paths, so we assume that nobody is
using it. We also don't plan on maintaining the non-Variable Width
Allocation code, so we are going to remove it.
Fixes [Feature #13381]
When passed a `fake_str`, `register_fstring` would create new strings
with `str_new_static`. That's not what was expected, and answer
almost no use cases.
Saves comitters' daily life by avoid #include-ing everything from
internal.h to make each file do so instead. This would significantly
speed up incremental builds.
We take the following inclusion order in this changeset:
1. "ruby/config.h", where _GNU_SOURCE is defined (must be the very
first thing among everything).
2. RUBY_EXTCONF_H if any.
3. Standard C headers, sorted alphabetically.
4. Other system headers, maybe guarded by #ifdef
5. Everything else, sorted alphabetically.
Exceptions are those win32-related headers, which tend not be self-
containing (headers have inclusion order dependencies).
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
