[backport release-3_22][processing] save NULL and empty values into different files in Split Vector Layer algorithm (fix #38105) #47030
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Description
Manual backport of the Split Vector Layer algorithm fix from #46997.
The Split Vector Layer algorithm exports both NULL and empty attribute values to the same filename, as a result one file overwrites another and some results are lost. Proposed PR assigns different suffixes for such files (_EMPTY and _NULL).
Fixes #38105.
Also fix unreported bug with displaying incorrect number of features written to each output file.