Querier panic with `{job="fluxy/prose",__name__!=""}`

[aaron7]

When executing {job="fluxy/prose",__name__!=""} across a range, we see a 422 Unprocessable Entity response.

{"status":"error","errorType":"execution","error":"unexpected error"}

We also see the querier panic.

level=error msg="parser panic: runtime error: invalid memory address or nil pointer dereference
panic(0x18ceb00, 0x281c420)
/usr/local/go/src/runtime/panic.go:489 +0x2cf

This does not occur with an instant query.

[leth]

This seems to be fixed in #583 ; I ran the query and saw no panics

[juliusv]

Yep, the LazySeriesIterator in the Prom1 Cortex is broken - I fixed this in the Prom2 port #583, which is hopefully soon ready for rollout.

[bboreham]

Closing as fixed in #583