http://d.puremagic.com/issues/show_bug.cgi?id=6993

           Summary: File.byLine runs on an empty file, fails enforcement
           Product: D
           Version: D2
          Platform: Other
        OS/Version: Windows
            Status: NEW
          Severity: major
          Priority: P2
         Component: Phobos
        AssignedTo: nobody@puremagic.com
        ReportedBy: andrej.mitrovich@gmail.com


--- Comment #0 from Andrej Mitrovic <andrej.mitrovich@gmail.com> 2011-11-22 21:04:53 PST ---
Create a new file "empty.d" and run this:

import std.stdio;

void main()
{
    auto file = File("empty.d", "r");
    foreach (aLine; file.byLine)
    {
    }
}

object.Exception@D:\DMD\dmd2\windows\bin\..\..\src\phobos\std\stdio.d(943):
Enforcement failed

Line 943:
enforce(file.isOpen);

So the file was not successfully opened, but why wasn't an exception thrown in the File constructor then?

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Jonathan M Davis <jmdavisProg@gmx.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |jmdavisProg@gmx.com
         Resolution|                            |DUPLICATE


--- Comment #1 from Jonathan M Davis <jmdavisProg@gmx.com> 2011-11-22 21:49:06 PST ---
I don't see any reason why an exception would be thrown from File's constructor for an empty file. It certainly doesn't say that it does. The problem is that ByLine clearly isn't set up to handle empty files correctly.

Duplicate of Bug# 6944

*** This issue has been marked as a duplicate of issue 6944 ***

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--- Comment #2 from Andrej Mitrovic <andrej.mitrovich@gmail.com> 2011-11-23 09:15:25 PST ---
(In reply to comment #1)
> I don't see any reason why an exception would be thrown from File's constructor for an empty file. It certainly doesn't say that it does. The problem is that ByLine clearly isn't set up to handle empty files correctly.
> 
> Duplicate of Bug# 6944
> 
> *** This issue has been marked as a duplicate of issue 6944 ***

I agree, but the file handle was closed so I *assumed* that meant the file was not opened. I would rather have byLine not iterate than throw just because a file is empty.

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--- Comment #3 from Jonathan M Davis <jmdavisProg@gmx.com> 2011-11-23 09:26:47 PST ---
Oh. I agree completely. I think that byLine should just be empty when the file is empty, so no iteration occurs. I don't know what the exact details of opening the file are, but I don't see why an empty file should throw when you try and open it. Certainly, File's docs don't say anything of the sort. In Linux however, I ended up hitting an assertion rather than the exception that you hit, so there may be system-dependent behavior going on.

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