Alloca is a fundmentally insecure way of doing allocations. Languages that promote alloca will find themselves stuck in a morass of security messes and buffer overflows. If Zig were to adopt alloca, it would make the catastrophic mistake that plagued C for over several decades and introduce permanently unfixable security issues for another generation of programming languages.
alloca is a significantly better and safer allocation strategy than the thing it supersedes (fixed size buffers). It's not great but it's definitely better.
I’ve been defending alloca() here, but no, strdupa() (not to be confused with shlwapi!StrDupA on Windows) is a bad idea. In cases that I think are acceptable, the size of the allocation is reasonably small and does not come from outside the program. Here you’re duplicating a string that you probably got somewhere else and don’t really control. That means you don’t really know if and when you’re going to overflow the stack, which is not a good position to be in.
(Once upon a time, MSLU, a Microsoft-provided Unicode compatibility layer for Windows 9x, used stack-allocated buffers to convert strings from WTF-16 to the current 8-bit encoding. That was also a bad idea.)
