[RFC] glob needs a way to do error reporting (eg unaccessible files)

[timotheecour]

this is related to nim-lang/Nim#13163

currently, walkGlob won't report any errors when trying to recurse inside dirs with invalid permissions.
there should be a way to report such errors; exactly how needs to be discussed;
eg:

• via a callback(we already have callbacks in api, filterDescend, and filterYield)
• (preferred IMO) by adding an additional field in GlobEntry, eg a ErrorKind

type ErrorKind=enum
  none,
  invalidPermission,
type
  GlobEntry* =
    tuple[path: string, kind: PathComponent, error: ErrorKind]

question is whether this would break any code

[haltcase]

@timotheecour I would also prefer option 2, but it is a breaking change. Any code using walkGlobKinds will break if it's using tuple destructuring:

# will fail when `GlobEntry` is a 3-tuple
for path, kind in walkGlobKinds():
  discard

# will work
for path, kind, error in walkGlobKinds():
  discard

I'm ok with that given we document the change properly and we're still < v1, although I wonder if we should change GlobEntry to be an object at that point in case anything else needs to be added. And maybe rename walkGlobKinds to something else (walkGlobEntries?).

[timotheecour]

• object seems better than tuple (for the exact reason you mentioned + other reasons)
• instead of breaking code, how about deprecating walkGlobKinds (via {.deprecated: "use walkGlobEntries".}) and adding walkGlobEntries ?

[haltcase]

Well, interestingly enough walkGlobKinds is technically the base implementation and walkGlob is just a wrapper that drops the kind.