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digitalmars.D.bugs - [Issue 6993] New: File.byLine runs on an empty file, fails enforcement

reply d-bugmail puremagic.com writes:
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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next sibling parent d-bugmail puremagic.com writes:
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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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prev sibling next sibling parent d-bugmail puremagic.com writes:
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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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prev sibling parent d-bugmail puremagic.com writes:
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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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