`setLenUninit(string)` was broken on the legacy refc backend when
growing within existing spare capacity.
`setLengthStrUninit` in `lib/system/sysstr.nim` only updated len when it
had to reallocate or when shrinking.
If oldLen < newLen <= capacity, it returned early without finalizing:
```nim
var s = newStringOfCap(10)
s.add("abc")
s.setLenUninit(6)
doAssert s.len == 6 # used to fail, len stayed 3
```
This escaped `tests/stdlib/tstring.nim` because the testing routine
`checkSetLenUninit` mostly resizes strings created at **exact**
length/capacity, so growth usually took the reallocating branch.
The new regression test covers the missing edge case.
So sorry for catching this only on the day of the stable release! In my
defense, the original PR hung in limbo for quite a while and it didn't
spend enough time in devel after the merge.
Adds `system.setLenUninit` for the `string` type. Allows setting length
without initializing new memory on growth.
- Required for a follow-up to #15951
- Accompanies #22767 (ref #19727) but for strings
- Expands `stdlib/tstring` with tests for `setLen` and `setLenUninit`
---------
Co-authored-by: Andreas Rumpf <araq4k@proton.me>
* make more standard libraries work with `nimPreviewSlimSystem`
* typo
* part two
* Delete specutils.nim
* fixes more tests
* more fixes
* fixes tests
* fixes three more tests
* add formatfloat import
* fix
* last
* Error -> Defect for defects
The distinction between Error and Defect is subjective,
context-dependent and somewhat arbitrary, so when looking at an
exception, it's hard to guess what it is - this happens often when
looking at a `raises` list _without_ opening the corresponding
definition and digging through layers of inheritance.
With the help of a little consistency in naming, it's at least possible
to start disentangling the two error types and the standard lib can set
a good example here.
