Clarify what limitations the RelX parsers have.

Signed-off-by: Magnus Therning <magnus@therning.org>

src/Path.hs

@@ -93,6 +93,8 @@ parseAbsDir filepath =
 -- | Get a location for a relative directory. Produces a normalized
 -- path which always ends in a path separator.
 --
+-- Note that @filepath@ may contain any number of @./@ but may not consist solely of @./@.  It also may not contain a single @..@ anywhere.
+--
 -- Throws: 'PathParseException'
 --
 parseRelDir :: MonadThrow m
@@ -125,6 +127,8 @@ parseAbsFile filepath =
 
 -- | Get a location for a relative file.
 --
+-- Note that @filepath@ may contain any number of @./@ but may not contain a single @..@ anywhere.
+--
 -- Throws: 'PathParseException'
 --
 parseRelFile :: MonadThrow m

test/Main.hs

@@ -150,12 +150,15 @@ parseRelDirSpec =
      failing "~/"
      failing "/"
      failing "./"
+     failing "././"
      failing "//"
      failing "///foo//bar//mu/"
      failing "///foo//bar////mu"
      failing "///foo//bar/.//mu"
      succeeding "foo.bak" (Path "foo.bak/")
      succeeding "./foo" (Path "foo/")
+     succeeding "././foo" (Path "foo/")
+     succeeding "./foo/./bar" (Path "foo/bar/")
      succeeding "foo//bar//mu//" (Path "foo/bar/mu/")
      succeeding "foo//bar////mu" (Path "foo/bar/mu/")
      succeeding "foo//bar/.//mu" (Path "foo/bar/mu/")
@@ -193,6 +196,8 @@ parseRelFileSpec =
      failing "///foo//bar/.//mu"
      succeeding "foo.txt" (Path "foo.txt")
      succeeding "./foo.txt" (Path "foo.txt")
+     succeeding "././foo.txt" (Path "foo.txt")
+     succeeding "./foo/./bar.txt" (Path "foo/bar.txt")
      succeeding "foo//bar//mu.txt" (Path "foo/bar/mu.txt")
      succeeding "foo//bar////mu.txt" (Path "foo/bar/mu.txt")
      succeeding "foo//bar/.//mu.txt" (Path "foo/bar/mu.txt")