FSFIRST/FSNEXT fail to detect subdirectories in Windows 10 1903 32-bit

[Yet Another Troll]

They also appear to throw error -33 on every call but still return something if the error is caught or ignored.

> ver
X11-BASIC Version: 1.27 Jul  8 2019 12:44:26
> load "\users\trollollio\onedrive\bas\0_dirwalk 1.bas"
> run
0       'd /'
Oopsie -33 * File %s not found
Calling FSNEXT - $Recycle.Bin
Calling FSNEXT - autoexec.bat
Calling FSNEXT - bootmgr
Calling FSNEXT - BOOTNXT
Calling FSNEXT - bootTel.dat
Calling FSNEXT - config.sys
Calling FSNEXT - Documents and Settings
Calling FSNEXT - hiberfil.sys
Calling FSNEXT - Intel
Calling FSNEXT - Logs
Calling FSNEXT - MSOCache
Calling FSNEXT - OneDriveTemp
Calling FSNEXT - pagefile.sys
Calling FSNEXT - PerfLogs
Calling FSNEXT - Program Files
Calling FSNEXT - ProgramData
Calling FSNEXT - Recovery
Calling FSNEXT - swapfile.sys
Calling FSNEXT - System Volume Information
Calling FSNEXT - TEST_TOOL
Calling FSNEXT - Users
Calling FSNEXT - Windows
Calling FSNEXT - Windows.old
Calling FSNEXT - Windows10Upgrade
Calling FSNEXT
1       1       0
0       'B0rk'
0 match(es) found.
OK
>

The code,

:::basic
#!/usr/bin/xbasic

Program DirWalkOnTheWildSide

 ' Can match all symbolic links with "s *" etc.
 ' TODO Convert this nasty NFA to an optimized DFA at run time
 Patterns$() = [ "*temp", "*tmp", "*sql*-v*", "*.mgr" ]
 Patterns$() = [ "*.wav", "*.mp3", "*.ogg", "*.amr", "*.fla", "*.flac" ]
 Patterns$() = [ "*.bas", "*.b", "*.cgi" ]
 PMFlags% = 16 ! Case insensitive GLOB() matching

 AllDirs$() = [ "d /" ]  ! Looking for adventure
 Matches$() = [ "B0rk" ] ! In whatever comes our way
 DirCount% = 1
 MatCount% = 0
 CurDir% = 0

 While CurDir% < DirCount%

  Clr P$, F$, S%
  P$ = AllDirs$(CurDir%)
  Print CurDir%, "'"; P$; "'"
  S% = InStr(P$, " ")
  ' Print "FindFirst '"; Mid$(P$, S% + 1, Len(P$) - S%); ; "'"
  ' Pause 0.1

  Clr F$
  ' Compiled code apparently doesn't like error handlers?
  ' On Error Cont
  On Error GoSub Mulligan ! We get one Mulligan per directory
  F$ = FSFirst$(Mid$(P$, S% + 1, Len(P$) - S%), "*", "dfa")
  ' If Len(F$) Then
  '  ' Use up our Mulligan if it's still unused
  '  Print 0xDEADBEEF / 0; Chr$(13);
  ' EndIf

  If Len(F$) = 0 Then
   ! No-op
  Else If Left$(P$, 2) = "d " Then
   ! No-op
  Else If Left$(P$, 2) = "s " Then
   ! No-op
  Else
   Print "Weird dir '"; P$; "' contains files like '"; F$; "'"
   Pause 5
  EndIf

  ' Discard the path's "d " or "s " prefix
  P$ = Mid$(P$, S% + 1, Len(P$) - S%)

  While Len(F$)
   S% = InStr(F$, " ")
   F$ = Left$(F$, S%) + P$ + Mid$(F$, S% + 1, Len(F$) - S%)
   ' Print "'"; F$; "'"
   ' Pause 0.1

   Clr WeHaveAContendah%, i%
   For i% = 0 To (UBound(Patterns$()) - 1)
    If Glob(F$, Patterns$(i%), PMFlags%) Then
     WeHaveAContendah% = True
     ' Is early exit just GOTO in drag?
     ' Would Dijkstra not like this?
     ' Break
     ' Exit For
    EndIf
    ' Exit If WeHaveAContendah%
   Next i%
   If WeHaveAContendah% Then
    Dim Matches$(MatCount% + 1)
    Matches$(MatCount%) = F$
    Inc MatCount%
    Print "Match "; MatCount%; " found '"; F$; "'"
    ' Pause 0.2
   EndIf

   If (Left$(F$, 2) = "d ") ! Or (Left$(F$, 2) = "s ") Then ! DO NOT FOLLOW SYMLINKS
    ' Directory, or symbolic link to maybe a directory?
    ' Could following symlinks cause an infinite loop? How to detect?
    If DirCount% = UBound(AllDirs$()) Then
     ' Hundreds of thousands of subdirectories!!!1!
     Print "REDIM PRESERVE AllDirs$("; DirCount% + (DirCount% Div 8) + 4; ")"
     Dim AllDirs$(DirCount% + (DirCount% Div 8) + 4)
    EndIf
    AllDirs$(DirCount%) = F$ + "/"
    Inc DirCount%
   Else If (Left$(F$, 2) = "- ") Then
    ' Ordinary file
    ! No-op
   Else If (Left$(F$, 2) = "s ") Then
    ' Symbolic link, can we find out what it points to?
    ! No-op
   Else
    ' We found something new!
    Dim Matches$(MatCount% + 1)
    Matches$(MatCount%) = F$
    Inc MatCount%
    Print "Weird "; MatCount%; '" found "; F$; "'"
    Pause 5
   EndIf

   Clr F$
   ' Is FSNEXT also prone to throwing exceptions? YES IT IS!
   Print "Calling FSNEXT ";
   F$ = "! UNKNOWN"
   On Error Cont ! GoSub Mulligan
   F$ = FSNext$()
   Print F$
  Wend
  Inc CurDir%
 Wend

 Print UBound(AllDirs$()), DirCount%, MatCount%
 For i% = 0 To (MatCount% - 1) ! Needs parens or it's a syntax error
  Print i%, "'"; Matches$(i%); "'"
 Next i%
 Print MatCount%; " match(es) found."

 Print "OK"
End

DefFn SubStr$(S$, First%, Last%) = Mid$(S$, First%, Last% - First% + 1)

Procedure Mulligan()
 Print "Oopsie ";
 E% = Err
 Print E%; " "; Err$(E%)
 Select E%
  Case 0   ! Divide by zero, not "all is well"
   ! No-op
  Case -13 ! Permission denied
   ! No-op
  Case -33 ! File not found (symlink to missing file/dir?)
   ! No-op
  Case -20 ! Not a directory (symlink to ordinary file?)
   ! No-op
  Default
   Stop
 EndSelect
 ' Pause 0.5
 ' Resume Next
Return

[Yet Another Troll]

...but the stepdir.bas sample does sometimes recognize subdirectories if root$ = "C:\"

I'll do more testing.

[Yet Another Troll]

I also see it in Windows 8.1 64-bit 6.3.9600 with the July Important patches installed but not the optional 2019-07 Preview of Monthly Quality Rollup for Windows 8.1 for x64-based Systems (KB4507463)

It could be the bug is in my code somehow, or FSFIRST/FSNEXT don't like "/" or "\" in Windows, or perhaps they need "C://" in order to indicate directories properly in the returned string instead of just "C:/"

[Markus Hoffmann]

I think, on WINDOWS, the root path "/" does not exist. So "d /" will cause that error.
However it probably defaults to something (like "C:/" or the current directory).
Have you tried to use "d C:/" on windows?

IF WIN32?
  AllDirs$() = [ "d C:/" ]  ! Looking for adventure
else 
AllDirs$() = [ "d /" ]  ! Looking for adventure
endif

[Yet Another Troll]

The first call to FSFIRST sort of succeeds, and the names of the files and directories in the root of the current drive, in this case C:, are found. It's just whatever is checking for -, d, or s that fails. I'll keep playing with it and/or finally dig into the sources. Thanks for looking at it.

[Yet Another Troll]

In a cmd window, DIR \ will list the root directory of the current drive. VB/VBA's Dir$ works similarly, so I expected FSFIRST/FSNEXT to also work like that,

Microsoft Windows [Version 10.0.18362.239]
(c) 2019 Microsoft Corporation. All rights reserved.

C:\Users\trollollio>dir \
 Volume in drive C has no label.
 Volume Serial Number is F696-BB0C

 Directory of C:\

10/29/2015  10:47 PM                24 autoexec.bat
10/29/2015  10:47 PM                10 config.sys
04/25/2016  01:33 PM    <DIR>          Intel
02/13/2016  05:19 AM    <DIR>          Logs
03/18/2019  07:46 PM    <DIR>          PerfLogs
07/18/2019  10:29 AM    <DIR>          Program Files
06/13/2016  01:08 AM    <DIR>          TEST_TOOL
07/18/2019  10:02 AM    <DIR>          Users
07/26/2019  06:40 AM    <DIR>          Windows
01/17/2018  03:55 PM    <DIR>          Windows10Upgrade
               2 File(s)             34 bytes
               8 Dir(s)  12,868,653,056 bytes free

C:\Users\trollollio>

Still, I may be better off inspecting environment variables like SystemRoot, ProgramData, ProgramFiles, and UserProfile to derive a list of drives to search, in case of a customized Windows installation spread amongst multiple drives or partitions. Such things were possible in the NT days and maybe still are.