?_trace=1 fails with datasette-geojson for some reason

[simonw]

view-source:https://calands.datasettes.com/calands/CPAD_2020a_SuperUnits.geojson?_sort=id&id__exact=4&_labels=on&_trace=1 is showing me a blank page.

[simonw]

The same URL with .json instead works fine: https://calands.datasettes.com/calands/CPAD_2020a_SuperUnits.json?_sort=id&id__exact=4&_labels=on&_trace=1

[eyeseast]

Where is _trace getting injected? And is it something a plugin should be able to handle? (If it is, I guess I should handle it in this case.)

[simonw]

The trace mechanism is a bit gnarly - it's actually done by some ASGI middleware I wrote, so I'm pretty sure the bug is in there somewhere: https://github.com/simonw/datasette/blob/280ff372ab30df244f6c54f6f3002da57334b3d7/datasette/tracer.py#L73

[eyeseast]

Just to add a wrinkle here, this loads fine: https://alltheplaces-datasette.fly.dev/alltheplaces/places.geojson?_trace=1

But also, this doesn't add any trace data: https://alltheplaces-datasette.fly.dev/alltheplaces/places.json?_trace=1

What am I missing?