panic on v0.0.76

[Vladikamira]

after an update to v0.0.76 we're facing such panic quite often, which leads to the Pod crash

{"level":"info","msg":"promxy starting with HTTP...","time":"2023-03-16T12:20:25Z"}
panic: runtime error: index out of range [3] with length 3

goroutine 85351 [running]:
github.com/prometheus/prometheus/promql.findPathRange({0xc002562a80, 0x3, 0x24e9240?}, {0xc0013d2280?, 0x1, 0xc001347d78?})
	/go/src/github.com/jacksontj/promxy/vendor/github.com/prometheus/prometheus/promql/engine_extra.go:18 +0x19b
github.com/prometheus/prometheus/promql.(*Engine).findMinMaxTime.func1({0x38ed608?, 0xc00168ec60?}, {0xc002562a80?, 0x3, 0x3})
	/go/src/github.com/jacksontj/promxy/vendor/github.com/prometheus/prometheus/promql/engine.go:768 +0x11a
github.com/prometheus/prometheus/promql/parser.inspector.Visit(0xc000d88b40, {0x38ed608?, 0xc00168ec60?}, {0xc002562a80?, 0xc001347e70?, 0x4151ba?})
	/go/src/github.com/jacksontj/promxy/vendor/github.com/prometheus/prometheus/promql/parser/ast.go:383 +0x43
github.com/prometheus/prometheus/promql/parser.Walk({0x3900f00, 0xc00011a008}, {0x38e45a0, 0xc000d88b40}, 0xc001f696d0, {0x38ed608, 0xc00168ec60}, {0xc002562a80, 0x3, 0x3}, ...)
	/go/src/github.com/jacksontj/promxy/vendor/github.com/prometheus/prometheus/promql/parser/ast.go:330 +0x209
github.com/prometheus/prometheus/promql/parser.Walk.func1(0x0, {0x38ed608, 0xc00168ec60})
	/go/src/github.com/jacksontj/promxy/vendor/github.com/prometheus/prometheus/promql/parser/ast.go:344 +0x225
created by github.com/prometheus/prometheus/promql/parser.Walk
	/go/src/github.com/jacksontj/promxy/vendor/github.com/prometheus/prometheus/promql/parser/ast.go:342 +0x405

We're having such panic on every Pod in the Deployment, so it would be easy to know if it's fixed.
there are around 400 requests per second on this Promxy instance, fyi

[jacksontj]

Thanks for the report, I'm looking into it but unable to trivially reproduce the issue (I'm still looking). If you could provide an example query to reproduce that would significantly speed up a fix, otherwise I'll continue digging in to see if I can find a repro case.

[jacksontj]

Alright, I was able to repro the issue and have a fix pending in #563

[Vladikamira]

Thanks! It works 🎉 no panic at all 👍