Stream-list does not pass on info/metadata

[robpvn]

Stream-list.js does not seem to preserve info/metadata like stream-scanline does. Scanline calls getInfo on the source to get the source's parameters and then pushes them onto the stream, preserving metadata. But Stream-list does not handle info at all (except for a require('Info') at the start which is then not used again), so outputs produced using streamlist have no metadata.

Is this intentional or an omission? I can see that copying all of the metadata from an original (including bounds info) when you use stream-list to only grab a portion of the tiles wouldn't be quite correct, but in my use case I'm copying a selection of vector tiles from a tmsource/mapnik XML and need to have the vector_layers json in the resulting mbtiles file in order for it to be useable.

[robpvn]

I looked at the MBTiles spec, and bounds are optional, so it seems one should be able to get away with snipping that out of the info object before passing it on. Same goes for center and maxzoom/minzoom, although I suspect that removing it might mess with some implementations expecting that metadata to be there? (As an aside, it looks like the mbtiles spec needs some updating to reflect current usage with vector tiles.)

[yhahn]

but in my use case I'm copying a selection of vector tiles from a tmsource/mapnik XML

Hrm, usually we do this using scanline or pyramid with a min/maxzoom + bounds parameters. Is there a reason you're using a list stream for this?

[robpvn]

I'm trying to generate tiles for a very non-rectangular area, Norway, so I wanted to skip processing lots of sea and Sweden/Finland. (Norway's bounding box in web-mercator is exceptionally wasteful!) I used tile-cover to generate a minimum list of tiles from a geojson outline, and then fed the list into the list stream. I'm of course open for alternate suggestions as to how best to accomplish this.