Thread overview
dirEntries throws exception on broken symlinks
Jan 05, 2014
dennis
Jan 05, 2014
FreeSlave
Jan 06, 2014
dennis
Jan 07, 2014
Timothee Cour
January 05, 2014
I a using dirEntries to list recursively build a list of all files in all subdirectories but dirEntries is throwing an exception when it encounters a broken link.

I want just report the exception, then ignore the broken link and then continue processing the rest of the dir's and files.

Do I need to create my own implementation of a dirEntries function to solve this?

Also in the example code below I am getting a segfault when I try to extract the errno from the exception object and I am not sure why the segfault is happening, is it my code or a bug?

Example Code:

import std.stdio;
import std.file;


void main(string[] args)
{

    try {
        foreach (string name; dirEntries(args[1], SpanMode.breadth))
        {
            writefln(name);
        }
    }
    catch(Exception o) {
        writefln(o.toString());
        writefln("%d",(cast(FileException)o).errno);

    }
}
January 05, 2014
You must not cast base class to derived class, when you don't know actual type (and even if you know exact type it's still bad practice to cast instance of more generic type to more specific one). Use multiple catch statements instead:

catch(FileException o)
{
//handle FileException
}
catch(Exception o)
{
//handle all other types of exceptions
}

About dirEntries, you need to move your try/catch statements into loop somehow. You probably should save result of dirEntries to variable and then make manual loop instead of foreach. Result of dirEntries is lazy, so it will not throw exception when you just get it.

It may look like

auto entries = dirEntries(your args);
while(!entries.empty)
{
    try
    {
        entry = entries.front;
        //do your stuff
    }
    //"catch" statements
    finally
    {
        entries.popFront();
    }
}
January 06, 2014
On Sunday, 5 January 2014 at 21:33:56 UTC, FreeSlave wrote:
> You must not cast base class to derived class, when you don't know actual type (and even if you know exact type it's still bad practice to cast instance of more generic type to more specific one). Use multiple catch statements instead:
>
> catch(FileException o)
> {
> //handle FileException
> }
> catch(Exception o)
> {
> //handle all other types of exceptions
> }
>
> About dirEntries, you need to move your try/catch statements into loop somehow. You probably should save result of dirEntries to variable and then make manual loop instead of foreach. Result of dirEntries is lazy, so it will not throw exception when you just get it.
>
> It may look like
>
> auto entries = dirEntries(your args);
> while(!entries.empty)
> {
>     try
>     {
>         entry = entries.front;
>         //do your stuff
>     }
>     //"catch" statements
>     finally
>     {
>         entries.popFront();
>     }
> }

Thank you for the quick feedback.  Your explanation of the two problems works for me.
January 07, 2014
I reported this here some time ago:
http://d.puremagic.com/issues/show_bug.cgi?id=11501 (dup of
http://d.puremagic.com/issues/show_bug.cgi?id=8298)
and there's a pull request ready, not sure why it isn't being merged


On Sun, Jan 5, 2014 at 10:20 PM, dennis <dennisr@visi.com> wrote:

> On Sunday, 5 January 2014 at 21:33:56 UTC, FreeSlave wrote:
>
>> You must not cast base class to derived class, when you don't know actual type (and even if you know exact type it's still bad practice to cast instance of more generic type to more specific one). Use multiple catch statements instead:
>>
>> catch(FileException o)
>> {
>> //handle FileException
>> }
>> catch(Exception o)
>> {
>> //handle all other types of exceptions
>> }
>>
>> About dirEntries, you need to move your try/catch statements into loop somehow. You probably should save result of dirEntries to variable and then make manual loop instead of foreach. Result of dirEntries is lazy, so it will not throw exception when you just get it.
>>
>> It may look like
>>
>> auto entries = dirEntries(your args);
>> while(!entries.empty)
>> {
>>     try
>>     {
>>         entry = entries.front;
>>         //do your stuff
>>     }
>>     //"catch" statements
>>     finally
>>     {
>>         entries.popFront();
>>     }
>> }
>>
>
> Thank you for the quick feedback.  Your explanation of the two problems works for me.
>