Fix WSOD when media source file is missing

[seth-shaw-unlv]

GitHub Ticket: N/A

What does this Pull Request do?

Adds a check to the MediaHasMimetype condition plugin to ensure a source file is found before attempting to call getMimeType() on it. This will only occur in rare instances where a file is missing from the media due to a bad migration (which happened to me) or other system failure.

What's new?

Adds the file variable returned from $this->mediaSource->getSourceFile($medium) (which returns false when no file is found) to the subsequent if statement and before the getMimeType check.

How should this be tested?

• Setup a condition using the MediaHasMimetype condition
• Make a node+media where the node would trigger the condition and the media's file field is empty. (Can't be done via the UI.)
• Visit the node page and experience the WSOD.
• Apply the PR
• Visit the node page again; it should load without error.

Interested parties

@Islandora/8-x-committers

[dannylamb]

These changes are prudent 👍

[dannylamb]

Oh, apparently i have to manually kick off the actions now? I guess I'll wait