Survey incomplete sidewalk tagging

[arrival-spring]

Some places only have sidewalk:left or sidewalk:right. I think this will usually imply that the other side has none, but I think it still counts as incomplete data (and would block #3735 - sidewalk surface quest).

This adds a bit more complexity than I'd hoped to the sidewalk filter, I wanted to do
and !sidewalk and !sidewalk:both and !(sidewalk:left and sidewalk:right)
but the NOT operator doesn't seem to work with brackets (it complained I'd closed too many brackets).

I wasn't about to get into rewriting the filter code, and maybe this filter is more readable than the above anyway.

Tested and works as expected, and all tests pass.

(I don't think this will have merge issues with #3735 but I'm happy to sort them if it does)

[westnordost]

and !sidewalk and !sidewalk:both and !(sidewalk:left and sidewalk:right)

Would be wrong anyway. That filter would always return true if e.g. only sidewalk:both but not any other sidewalk:* was set

[arrival-spring]

Now branched from #3735 - sidewalk surface quest

Thanks for the tip, I've now done the filters here in a similar way to AddCycleway, so any incomplete or overloaded tagging is now surveyed every time.

Runs as expected, and all tests pass.

[westnordost]

Something is wrong, the diff also includes changes from your other PR even though it is merged now

[arrival-spring]

Something is wrong, the diff also includes changes from your other PR even though it is merged now

It seems that's a bug in Github

I've sorted it now

[westnordost]

Looks good to me, thank you! I find it very important though to have a test for SidewalkParser

[arrival-spring]

Tests added (and fixed a couple of edge cases whilst at it).

When using only one of sidewalk:left and sidewalk:right SidewalkParser currently returns INVALID for the other side (rather than null).

I'm not sure if this matters, I didn't change it because it would mean adding a check for any side being null in AddSidewalk (in addition to checking for any side being INVALID.

[westnordost]

Cool, you even found some bugs with that! The tests are really easy to read, well done!

When using only one of sidewalk:left and sidewalk:right SidewalkParser currently returns INVALID for the other side (rather than null).

Hmm, I think this is fair. It would be OK either way. The important part is that the app asks the user to complete the information if it is incomplete / ambiguous this way. So, whatever you think is best.