Weird behavior of FeatureMerger - Some features aren't output through any port

Hey. I solved the problem with a NullAttributeMapper transformer. But still, I don't understand why the features weren't output through the UnmergedRequestor port.

@timotheebecker​ If you can attach the sample data we can look into the why's in more detail.

Hi @markatsafe.

Here attached is a workbench and data. I have come against the same problem again with different datasets.

Thanks in advance.

@timotheebecker​ Thanks for the reproduction data & workspace. I couldn't reproduce the issue in FME 2021.2:

Perhaps try changing the Excel reader behaviour to treat empty cells as <null> rather then the default <missing> . <nulls> are generally treated as real citizens in FME were as <missing> implies the attribute doesn't exist.

If that doesn't work - can you identify the 5 records that do not join?

Hi @Mark Stoakes​ !

Yes, what you suggest works ! I suppose it's even better than what I had done : adding NullAttributeMappers (which do the exact same thing).

I suppose that is a good practise with Excel files to choose the option "Read blank cells as Null".

But I still find it weird.

Here below is a screenshot of an even simpler testcase. I attempt to merge two times the same file (just duplicated and named differently).

And it still doesn't merge when Read blank cells is set to Missing. I suppose this is "As designed". I wonder what the logic behind is...