Make error messages include more information when migrating files

Running tests.

I'm new to Drupal and it's community, so I don't have the knowledge or the time right now to write a test and make this a patch, but this code was very useful to me in 'making error messages include more information', at least for file migrations. I simply added a try/catch to the copyFile function in modules\migrate\plugins\destinations\file.inc and added the exception message to the migration message. My new function reads as follows:

protected function copyFile($destination) {
	$this->sourcePath = self::urlencode($this->sourcePath);
	try {
		if (copy($this->sourcePath, $destination)) {
			return TRUE;
		}
	} catch (Exception $e) {
		$migration = Migration::currentMigration();
		$migration->saveMessage(t('The specified file %file could not be copied to ' .
			'%destination. Error: ' . $e->getMessage(),
			array('%file' => $this->sourcePath, '%destination' => $destination)));
		return FALSE;
	}
}

As much time as various un-informative errors have cost our team, I thought it would be more helpful to the community to put this out there than to wait until I could submit it as a proper patch.

@dan3h: Could you submit a proper Drupal patch? tl;dr - do a git diff in the module directory.

Thanks.

I badly needed this to debug a WordPress import. I created a patch from @dan3h's code, but with typos and formatting fixed.

Error message before:

The specified file http://www.domain.se/wp-content/uploads/1234.png could not be copied to public://wp-content/uploads/1234.png.

Error message after:

The specified file http://www.domain.se/wp-content/uploads/1234.png could not be copied to public://wp-content/uploads/1234.png: "copy(): http:// wrapper is disabled in the server configuration by allow_url_fopen=0 File C:\wamp\www\abc\sites\all\modules\contrib\migrate\plugins\destinations\file.inc, line 410"

Committed, thanks!