Improve handling of incorrect paths in validator

[notartom]

If a path is incorrect in the validator, this is not handled gracefully, and instead we get a whole bunch of errors because the following code in application/libraries/Librivox_mp3gain.php that parses the mp3gain output does not have a second line to work with:

$this->flag     = ' -o  ';
$command = $this->mp3gain .  ' ' . $this->flag . $dir. $file_name;
exec($command, $output);
$parts = explode("\t", $output[1]);

Here's a screenshot of an incorrect validator path (notice the period at the end of the first file):

And here are the PHP errors we get:

A PHP Error was encountered
Severity: Notice
Message: Undefined offset: 1
Filename: libraries/Librivox_mp3gain.php
Line Number: 73

A PHP Error was encountered
Severity: Notice
Message: Undefined index: playtime_string
Filename: libraries/Librivox_id3tag.php
Line Number: 171

A PHP Error was encountered
Severity: Notice
Message: Undefined offset: 2
Filename: libraries/Librivox_id3tag.php
Line Number: 172

A PHP Error was encountered
Severity: Notice
Message: Undefined index: audio
Filename: libraries/Librivox_id3tag.php
Line Number: 173

A PHP Error was encountered
Severity: Notice
Message: Undefined index: audio
Filename: libraries/Librivox_id3tag.php
Line Number: 177

A PHP Error was encountered
Severity: Notice
Message: Undefined index: audio
Filename: libraries/Librivox_id3tag.php
Line Number: 179

[twinkietoes-on]

This is happening frequently; a timely fix would be very helpful!

I also have this issue, the first two files are the guilty ones. I added them separately, the original two were renamed with the date, but now I can't edit the ID tags for the new ones (or for all in general) because of this error: All files must be linked to sections before you can edit the tags
https://librivox.org/validator/16345
Also, when I try to delete any file, all buttons freeze and I can't click anything, only after I refresh.

A PHP Error was encountered
Severity: Notice
Message: Undefined offset: 1
Filename: libraries/Librivox_mp3gain.php
Line Number: 71

A PHP Error was encountered
Severity: Notice
Message: Undefined index: playtime_string
Filename: libraries/Librivox_id3tag.php
Line Number: 171

A PHP Error was encountered
Severity: Notice
Message: Undefined offset: 2
Filename: libraries/Librivox_id3tag.php
Line Number: 172

A PHP Error was encountered
Severity: Notice
Message: Undefined index: audio
Filename: libraries/Librivox_id3tag.php
Line Number: 173

A PHP Error was encountered
Severity: Notice
Message: Undefined index: audio
Filename: libraries/Librivox_id3tag.php
Line Number: 177

A PHP Error was encountered
Severity: Notice
Message: Undefined index: audio
Filename: libraries/Librivox_id3tag.php
Line Number: 179

A PHP Error was encountered
Severity: Notice
Message: Undefined offset: 1
Filename: libraries/Librivox_mp3gain.php
Line Number: 71

A PHP Error was encountered
Severity: Notice
Message: Undefined index: playtime_string
Filename: libraries/Librivox_id3tag.php
Line Number: 171

A PHP Error was encountered
Severity: Notice
Message: Undefined offset: 2
Filename: libraries/Librivox_id3tag.php
Line Number: 172

A PHP Error was encountered
Severity: Notice
Message: Undefined index: audio
Filename: libraries/Librivox_id3tag.php
Line Number: 173

A PHP Error was encountered
Severity: Notice
Message: Undefined index: audio
Filename: libraries/Librivox_id3tag.php
Line Number: 177

A PHP Error was encountered
Severity: Notice
Message: Undefined index: audio
Filename: libraries/Librivox_id3tag.php
Line Number: 179

[notartom]

The change from the PR is on the server. @twinkietoes-on does it make sense? I'm basically just skipping any file that mp3gain cannot process for whatever reason.

[notartom]

Alright, I think the commit above (7f63d1c) should prevent broken files form reaching the validator. Is that the only problem though? What about the filenames with the period at the end? How do they end up happening?

[redrun45]

I was able to reproduce this one last night. A bug in a feature we don't seem to use anymore. This is much less urgent now that the warning messages don't interfere with AJAX requests, but worth fixing when the dust settles on other changes.