#158 EListError when add/deleting same filename multiple (3) times.

[Barry Staes]

I have found that calling TAbZipKit.DeleteAt() before TAbZipKit.AddFromStream(), for the 3th time with the same filename, results in an EListError exception.

When using identical filenames, this takes just three attempts:

• TAbZipKit.AddFromStream()
• TAbZipKit.DeleteFiles()
• TAbZipKit.AddFromStream()
• TAbZipKit.DeleteFiles()
• TAbZipKit.AddFromStream() // <-- EListError: List index out of bounds (-1)
  When using random filenames, this happens after the same filename is add/deleted three times.
  The attached console program demonstrates this.

Exception seems to be caused by AddFromStream() and raised in TAbArchiveList.Get(), see stacktrace:

• Classes.TList.Get(???)
• TAbArchiveList.Get
• AbArcTyp.TAbArchiveList.Get(-1)
• AbArcTyp.TAbArchive.AddFromStream('file.txt', stream)

I have also seen:

• TAbCustomZipKit.ExtractToStream() causes TAbArchiveList.Get() to raise EListError
• TAbCustomZipKit.ExtractToStream() causes TAbArchive.FindFile() to raise EAccessViolation
• TAbCustomZipKit.ExtractToStream() causes TAbArchiveList.Find() to raise EPrivilege
  Which is why DeleteAt() is my suspect. I do not grasp the internal hash mechanism, but perhaps it does not update the hash list correctly?

Tested with TpAbbrevia v5.0, svn revision 530.

[Barry Staes]

I think i can further narrow it down and say that EListError occurs after DeleteAt() is called 3 times for files that where added by AddFromStream().

So whenever a file already exists in an opened file, it can be deleted 4 times in total.
Workaround is reopening whole archive after each DeleteAt(), as example shows.

[Barry Staes]

I can verify that the problem still exists in the latest svn revision 536.

Capeterson please run attached demo DPR to reproduce EListError exception and mark this issue as verified.