[ANN] Lua 5.4.9 (rc1) now available

[Luiz Henrique de Figueiredo]

Lua 5.4.9 (rc1) is now available for testing at
https://www.lua.org/work/lua-5.4.9-rc1.tar.gz

The SHA256 checksum is
2335b6c582a52654f94612bf10d2f4672805d05329aa6568b1d8cd9e5c6fb8e6  -

The Git commit ID in branch v5.4 is
312b9efaa1061c2c4cad08554dbc1351c3270eef

Lua 5.4.9 fixes all bugs listed in
https://www.lua.org/bugs.html#5.4.8

The complete diffs from Lua 5.4.8 are available at
https://www.lua.org/work/diffs-lua-5.4.8-lua-5.4.9.html
https://www.lua.org/work/diffu-lua-5.4.8-lua-5.4.9.html

This is probably the last release of Lua 5.4.
Now is the time to report glitches and to try to fix any remaining bugs.

We thank everyone for their feedback on Lua 5.4 till now.

All feedback welcome. Thanks.
--lhf

[blogdron (BLOGDRON)]

Thanks!

понедельник, 10 августа 2026 г. в 12:36:15 UTC+3, Luiz Henrique de Figueiredo:

[Richard Beckmann]

Dear Lua developers

The '__builtin_expect' fix in Lua 5.5.1 hasn't been backported to Lua 5.4.9 (rc1).

In Lua 5.5.1 'luaconf.h' at line 656

```

#if !defined(LUA_NOBUILTIN) && defined(__GNUC__) && (__GNUC__ >= 3)

#define luai_likely(x) (__builtin_expect(((x) != 0), 1))

#define luai_unlikely(x) (__builtin_expect(((x) != 0), 0))

#else

#define luai_likely(x) (x)

#define luai_unlikely(x) (x)

#endif

#endif

```

In Lua 5.4.9 (rc1) 'luaconf.h' at line 683

```

#if defined(__GNUC__) && !defined(LUA_NOBUILTIN)

#define luai_likely(x) (__builtin_expect(((x) != 0), 1))

#define luai_unlikely(x) (__builtin_expect(((x) != 0), 0))

#else

#define luai_likely(x) (x)

#define luai_unlikely(x) (x)

#endif

#endif

```

The luai_likely/luai_unlikely code from Lua 5.4.9 should be the same as the code from Lua 5.5.1 with the fix in which the GNU compiler version is too low.

Sincerely,

Richard Beckmann

Sent with Proton Mail secure email.

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[Roberto Ierusalimschy]

> The '__builtin_expect' fix in Lua 5.5.1 hasn't been backported to Lua 5.4.9 (rc1).

Thanks for the feedback.

-- Roberto