Backward compatibility or valid input

Hi there,

We've got an issue from an LO user about that LO does not import some tool generated Writer 
documents. I found that it's the same issue which was already reported here:
https://bugs.documentfoundation.org/show_bug.cgi?id=100033
and was closed as won't fix. I'm not sure this was the right way to handle this bug. It was said 
that the documents are invalid, so LO don't need to import it properly. The problem with this 
argument is that in earlier versions LO used to import those documents without a problem.

I thought backward-compatibility is important in LO project (after that exhaustive discussion about 
API backward compatibility). This document was loaded in earlier versions properly and so this can 
be seen as a regression from the user point of view. I'm thinking of reverting this commit which 
changes LO behavior:
https://cgit.freedesktop.org/libreoffice/core/commit/?id=de0432a9256188c7b5cd1a83858311e68c890ebf
Next to that, this commit causes a regression, it also a bit weird actually, since it still allows 
to have two frames with the same name (which was said to be invalid). It drops duplicated frames 
only from the third duplicate. So LO still accept invalid documents, which inconsistency makes LO 
behavior more unpredictable. I think the best would be to revert this commit and try to find an 
other fix for the issue for which this commit was added as a workaround (I expect this was a 
workaround since commit message speaks about crash and loading time which can be fixed only 
indirectly by droping some content).

Caolan, I don't see a bug number in the commit message. So I don't know what was the actual test 
case there. Do you remember something about what was the issue? Maybe we can find a better solution 
for that.

Thanks,
Tamás