CacheFileMetadataIndex does not delete rows in ExoPlayerCacheFileMetadata table after removing file from cache. Is this normal?

[hans-de-clercq]

Issue description

I'm creating an app to play music with crossfade mixes. To play music in the background, I use a foreground service.

I use ProgressiveDownloader to download the next track in the background before preparing. To prepare the player, I use a ProgressiveMediaSource.Factory with a CacheDataSourceFactory and a SimpleCache.
This seems to work perfectly. When a track is played, the track is removed from the cache with ProgressiveDownloader.remove(). The deletion of the track seems to work, but the database table, named ExoPlayerCacheFileMetadata4f582135912e0071 apparently does not remove the matching row. The deletion of the row in table ExoPlayerCacheIndex4f582135912e0071 gets executed correctly. Is this a normal procedure or a small bug?

I also tried the ExoPlayer demo app and when removing a download, I got the same. 0 rows are altered when executing the query to remove a row from the ExoPlayerCacheFileMetadata table in CacheFileMetadataIndex.java.

Reproduction steps

When I debug my app, I enter this method in CacheFileMetadataIndex.java (via CacheUtil.remove(cache, key) -> SimpleCache.removeSpan(span) -> SimpleCache.removeSpanInternal(span))

public void remove(String name) throws DatabaseIOException {
    Assertions.checkNotNull(tableName);
    try {
      SQLiteDatabase writableDatabase = databaseProvider.getWritableDatabase();
      writableDatabase.delete(tableName, WHERE_NAME_EQUALS, new String[] {name});
    } catch (SQLException e) {
      throw new DatabaseIOException(e);
    }
  }

When I dig deeper in these methode, a SQLStatement is created to remove the matching row in the database, something like DELETE FROM ExoPlayerCacheFileMetadata1e75b6426726c95c WHERE 0 = ? with bindArgs 0="3.0.1573029543652.v3.exo". This row exists in the database. No error is thrown in the next steps of the code executing this SQL statement, but when the SQL statement is executed, 0 is returned as nb rows affected. All the parameters and data seem ok, but the query does not delete the row.

Version of ExoPlayer being used

ExoPlayer version used: 2.10.1

Device(s) and version(s) of Android being used

I tried this on emulators with API 27 and API 29, and on my Samsung J5 device with API 23.

[ojw28]

Yes, this is a small bug. WHERE 0 = ? should be WHERE name = ?. We'll get that fixed.