import nativesockets raises error with enabled useNimRtl

[capocasa]

Nim Version

Nim Compiler Version 2.0.2 [Linux: amd64]
Compiled at 2023-12-15
Copyright (c) 2006-2023 by Andreas Rumpf

git hash: c4c44d1
active boot switches: -d:release

Description

# rtltest.nim
import nativesockets

echo "foo"

nim c -d:release -d:useRtl rtltest

Current Output

/home/carlo/.choosenim/toolchains/nim-2.0.2/lib/pure/nativesockets.nim(388, 52) template/generic instantiation from here
/home/carlo/.choosenim/toolchains/nim-2.0.2/lib/pure/nativesockets.nim(453, 18) Error: setSlice(ipStr) do:
  7 .. pred(strAddrLen, 1) can have an unlisted effect: RootEffect

Expected Output

Hint: mm: orc; threads: on; opt: none (DEBUG BUILD, `-d:release` generates faster code)
52820 lines; 0.844s; 71.148MiB peakmem; proj: /home/carlo/rtltest; out: /home/carlo/rtltest [SuccessX]

Known Workarounds

Use -d:useMalloc in both loading program and library and do not use -d:useNimRtl

Additional Information

No response

[capocasa]

Experimented a bit, added tag RootException to getHostByAddr (lib/pure/nativesockets.nim line 395), which stopped that error, unsure what other effects that has.

After that, some code calling getCurrentException() produced getCurrentException() can raise an unlisted exception: Exception. So the flag useNimRtl seems to somehow change the behavior of the effects system in multiple ways. I compared with strictEffects but the latter compiled all my code normally.

[ringabout]

See also #23162 #23163

[capocasa]

Added a workaround to description (Use -d:useMalloc in both loading program and library and do not use -d:useNimRtl)

[capocasa]

@ringabout Thanks for the connect! These seem like the same problem. They should be easy enough to fix but I feel a bit clueless to where to start to look.