Nimscript listFiles should throw exception when path is not found

[dom96]

listFiles will silently return no items if the path specified does not exist, this can make it seem like a command has worked when it in fact has not.

Example

task render, "Renders SVGs to PNGs":
  for file in listFiles(getCurrentDir() / "bad_path"):
    discard

Current Output

Nothing

Expected Output

Exception

[genotrance]

listFiles() uses walkDir() which itself doesn't raise an exception when it is a bad directory, at least on Linux.

https://github.com/nim-lang/nim/blob/devel/lib/pure/os.nim#L2087

[timotheecour]

as mentioned here #13642 this issue should be re-opened as the bug is still there; #13642 would fix this

[timotheecour]

@Araq after @narimiran 's changes to #13642, this issue is still unfixed, which is really misleading.
3 choices:

• 1: mark as wontfix or reopen
• 2: introduce listFiles(dir, checkDir = false)
• 3: mark listFiles with {.deprecated: "use os.walkDir".}, os should be used in nimscript now that it works well instead of arbitrarily introducing a large number of alternate API's specific to nimscript (listFiles etc used to make sense for nimscript due to prior limitations but not anymore) (but double check that it does work, right now some adjustments would still be needed)

my preference is option 3

[timotheecour]

note that #13642 (even without the changes) would not have helped for VM code; so I went for a more general fix instead, see #13714 which fixes this issue and a host of other issues related to exceptions in VM callbacks (including nimscript and nimvm)

[Araq]

option 3 sounds good to me too.