quotes in CPU profile tags not escaped properly

What version of pprof are you using?

00490a63f31712a6991b73391dd3decdada278d0 (i.e. main as of today), but the problem exists in all prior versions. I first stumbled upon it in Go 1.19.

What operating system and processor architecture are you using?

Irrelevant

What did you do?

Run pprof -dot on the provided file (this is a CPU profile taken of a CockroachDB 23.1 node, but these details don't matter). Note how the resulting .dot file is invalid since the " occurring in a label was not properly escaped:

N36_0 [label = "range_str:12419/2:/Table/136/1/"{NHCH-…-PWN-a"}" id="N36_0" fontsize=8 shape=box3d tooltip="0.01s"]

pprof.pb.gz.txt pprof.dot.txt

What did you expect to see?

The " in the label should have been escaped, resulting in a valid .dot file.

What did you see instead?

An invalid dot file, which in particular implies that the graph view in pprof isn't working. The line above should have been

N36_0 [label = "range_str:12419/2:/Table/136/1/\"{NHCH-…-PWN-a\"}" id="N36_0" fontsize=8 shape=box3d tooltip="0.01s"]

which would work.

I gave it a half-hearted attempt at fixing, but it seemed like there might be more than one place where the escaping isn't happening properly and it wasn't super clear to me where we'd need to throw in an escapeForDot^1 on top of here:

https://github.com/google/pprof/blob/a41b82acbcb1f6a6d0998b0fddeb1f1adb7d8fc1/internal/graph/dotgraph.go#L251

Also, it seems useful to add testing for these sorts of things.