isValidFilename seems incorrect or misleading

[timotheecour]

Example 1

when true:
  import std/os
  let name = " foo.tmp"
  writeFile(name, "baz") # works
  echo isValidFilename(name) # false

Current Output

false

Expected Output

true, since writeFile works

Example 2

the example should be converted to runnableExamples

Example 3

isValidFilename("") crashes

Possible Solution

• add an optional param to isValidFilename to specify whether the filename is actually valid or (subjective) follows recommended guidelines (eg no space)
• or fix isValidFilename implementation
• or at very least clarify semantics in doc comments

Additional Information

1.5.1 ee6d561
on osx

i was exploring whether to use this to address #17914 (comment) but turns out it's useless for this purpose (and also doesn't check presence of DirSep etc)

[juancarlospaco]

It says func only checks filenames very explicit, separators are not part of the "filename" by definition.

It is for when you need that a filename works on all OS without problems,
some filenames works on a given OS, and crash in another OS,
example you can create a file named CON on Linux, but it crashes your Windows.

Who wants filenames with trailing whitespaces anyway?.

Therefore "writeFile works" is not an absolute way to determine anything.
🤷

[juancarlospaco]

Maybe a new isValidPath() ?,
should it check whole paths, including separators, if the disk actually exists (C:/, Z:/, /something/, samba:/, etc),
if the disk is mounted, if the disk is an unix NFS is it network reachable, if the disk is an SSHFS do you have the keys,
may get more complicated, and not as cheap as the filename check, etc.

[haoyu234]

why not isValidFileName, just like randomPathName #17898