Program: 110208
Project: 110208
Buggy source:
/** 
 * Opens the next source. If the cache contains data spanning the current read position then  {@link #cacheReadDataSource} is opened to read from it. Else {@link #upstreamDataSource} isopened to read from the upstream source and write into the cache.
 * @param checkCache If true tries to switch reading from or writing to cache instead of readingfrom upstream. If the switch isn't possible then returns without changing source.
 */
private void openNextSource(boolean checkCache) throws IOException {
  CacheSpan nextSpan;
  if (currentRequestIgnoresCache) {
    nextSpan=null;
  }
 else   if (blockOnCache) {
    try {
      nextSpan=cache.startReadWrite(key,readPosition);
    }
 catch (    InterruptedException e) {
      throw new InterruptedIOException();
    }
  }
 else {
    nextSpan=cache.startReadWriteNonBlocking(key,readPosition);
  }
  DataSpec nextDataSpec;
  DataSource nextDataSource;
  if (nextSpan == null) {
    nextDataSource=upstreamDataSource;
    nextDataSpec=new DataSpec(uri,readPosition,bytesRemaining,key,flags);
  }
 else   if (nextSpan.isCached) {
    Uri fileUri=Uri.fromFile(nextSpan.file);
    long filePosition=readPosition - nextSpan.position;
    long length=nextSpan.length - filePosition;
    if (bytesRemaining != C.LENGTH_UNSET) {
      length=Math.min(length,bytesRemaining);
    }
    nextDataSpec=new DataSpec(fileUri,readPosition,filePosition,length,key,flags);
    nextDataSource=cacheReadDataSource;
  }
 else {
    long length;
    if (nextSpan.isOpenEnded()) {
      length=bytesRemaining;
    }
 else {
      length=nextSpan.length;
      if (bytesRemaining != C.LENGTH_UNSET) {
        length=Math.min(length,bytesRemaining);
      }
    }
    nextDataSpec=new DataSpec(uri,readPosition,length,key,flags);
    if (cacheWriteDataSource != null) {
      nextDataSource=cacheWriteDataSource;
    }
 else {
      nextDataSource=upstreamDataSource;
      cache.releaseHoleSpan(nextSpan);
      nextSpan=null;
    }
  }
  if (!currentRequestIgnoresCache && nextDataSource == upstreamDataSource) {
    checkCachePosition=readPosition + MIN_READ_BEFORE_CHECKING_CACHE;
    if (checkCache) {
      return;
    }
  }
 else {
    checkCachePosition=Long.MAX_VALUE;
  }
  closeCurrentSource();
  if (nextSpan != null && nextSpan.isHoleSpan()) {
    currentHoleSpan=nextSpan;
  }
  currentDataSource=nextDataSource;
  currentDataSpecLengthUnset=nextDataSpec.length == C.LENGTH_UNSET;
  long resolvedLength=nextDataSource.open(nextDataSpec);
  if (currentDataSpecLengthUnset && resolvedLength != C.LENGTH_UNSET) {
    setBytesRemaining(resolvedLength);
  }
}

Fixed version (ground truth):
/** 
 * Opens the next source. If the cache contains data spanning the current read position then  {@link #cacheReadDataSource} is opened to read from it. Else {@link #upstreamDataSource} isopened to read from the upstream source and write into the cache. <p>There must not be a currently open source when this method is called, except in the case that  {@code checkCache} is true. If {@code checkCache} is true then there must be a currentlyopen source, and it must be  {@link #upstreamDataSource}. It will be closed and a new source opened if it's possible to switch to reading from or writing to the cache. If a switch isn't possible then the current source is left unchanged.
 * @param checkCache If true tries to switch to reading from or writing to cache instead ofreading from  {@link #upstreamDataSource}, which is the currently open source.
 */
private void openNextSource(boolean checkCache) throws IOException {
  CacheSpan nextSpan;
  if (currentRequestIgnoresCache) {
    nextSpan=null;
  }
 else   if (blockOnCache) {
    try {
      nextSpan=cache.startReadWrite(key,readPosition);
    }
 catch (    InterruptedException e) {
      throw new InterruptedIOException();
    }
  }
 else {
    nextSpan=cache.startReadWriteNonBlocking(key,readPosition);
  }
  DataSpec nextDataSpec;
  DataSource nextDataSource;
  if (nextSpan == null) {
    nextDataSource=upstreamDataSource;
    nextDataSpec=new DataSpec(uri,readPosition,bytesRemaining,key,flags);
  }
 else   if (nextSpan.isCached) {
    Uri fileUri=Uri.fromFile(nextSpan.file);
    long filePosition=readPosition - nextSpan.position;
    long length=nextSpan.length - filePosition;
    if (bytesRemaining != C.LENGTH_UNSET) {
      length=Math.min(length,bytesRemaining);
    }
    nextDataSpec=new DataSpec(fileUri,readPosition,filePosition,length,key,flags);
    nextDataSource=cacheReadDataSource;
  }
 else {
    long length;
    if (nextSpan.isOpenEnded()) {
      length=bytesRemaining;
    }
 else {
      length=nextSpan.length;
      if (bytesRemaining != C.LENGTH_UNSET) {
        length=Math.min(length,bytesRemaining);
      }
    }
    nextDataSpec=new DataSpec(uri,readPosition,length,key,flags);
    if (cacheWriteDataSource != null) {
      nextDataSource=cacheWriteDataSource;
    }
 else {
      nextDataSource=upstreamDataSource;
      cache.releaseHoleSpan(nextSpan);
      nextSpan=null;
    }
  }
  checkCachePosition=!currentRequestIgnoresCache && nextDataSource == upstreamDataSource ? readPosition + MIN_READ_BEFORE_CHECKING_CACHE : Long.MAX_VALUE;
  if (checkCache) {
    Assertions.checkState(currentDataSource == upstreamDataSource);
    if (nextDataSource == upstreamDataSource) {
      return;
    }
    try {
      closeCurrentSource();
    }
 catch (    Throwable e) {
      if (nextSpan.isHoleSpan()) {
        cache.releaseHoleSpan(nextSpan);
      }
      throw e;
    }
  }
  if (nextSpan != null && nextSpan.isHoleSpan()) {
    currentHoleSpan=nextSpan;
  }
  currentDataSource=nextDataSource;
  currentDataSpecLengthUnset=nextDataSpec.length == C.LENGTH_UNSET;
  long resolvedLength=nextDataSource.open(nextDataSpec);
  if (currentDataSpecLengthUnset && resolvedLength != C.LENGTH_UNSET) {
    setBytesRemaining(resolvedLength);
  }
}