Underflow of unsigned int

Some unsigned int are initialized to value -1 e.g.: MemBlock.hpp#L145

  void reset() noexcept {
    m_fileid = -1;
    m_fileBlock = -1;
    m_fSeq = -1;
    m_tapeFileBlock = -1;
    m_payload.reset();
    
    //delete the previous m_context (if allocated) 
    //and set the new one to nullptr
    m_context.reset();
  }

...

  /** CASTOR NsFileId file concerned */
  uint64_t m_fileid;

  /** number of the memory-chunk of the current file we are manipulating */
  uint64_t m_fileBlock;
  
  /** order of file on the tape */
  uint64_t m_fSeq;
  
  /** Sequence number of the first tape block file in this memory block */
  size_t m_tapeFileBlock;
  
  /** Size of the tape blocks, allowing sanity checks on the disk write side in recalls */
  size_t m_tapeBlockSize;

added cta: Tape server typebug labels

added Code Quality label

changed title from Overflow of unsigned int to Underflow of unsigned int

assigned to @afonso

assigned to @jchodak

Problem seen here, for example:

• #1082

marked this issue as related to #1082

mentioned in merge request !825 (merged)

By looking into the code, it seems that -1 is just used as a placeholder for "no value".

It was probably necessary because all these counters (m_fileid, m_fileBlock, m_fSeq, m_tapeFileBlock) start on zero.

Except for misleading log values, I think no urgent fix is neecessary. However, their type can be easily replaced by std::optional<T>, which is a better fit for this use case instead of -1.

mentioned in issue #1082

added workflowin review label

closed with merge request !825 (merged)

mentioned in commit 758ac23c

mentioned in merge request !844 (merged)

mentioned in commit 948ca466