Setting array length without initializing/reallocating.

[Bastiaan Veelo]

On Saturday, 12 December 2020 at 00:53:09 UTC, Jonathan Levi 
wrote:
> Wow, there went several hours of debugging.
>
> Increasing the length of a slice, by setting its length, will 
> initialize the new elements and reallocate if necessary.
>
> I did not realize length was "smart", I guess I should have 
> guessed.
>
> Anyway, to work around this, and probably also be more clear, 
> create a new slice from the same pointer.
>
> `array = array.ptr[0..newLength];`

Hold on -- how does this not corrupt memory? As soon as the 
length exceeds the allocated capacity (the point at which the 
slice would be reallocated when setting its length) you will have 
a silent out of bounds violation, identical to overflowing a C 
array.

Am I wrong??

If you do not want the expansion to be initialized, I guess you 
could allocate a new uninitialized slice and copy contents over 
explicitly.

--Bastiaan.