invalid xml from `xctrace`

[jarjk]

I suppose it's not flamegraph's fault, but still...

I get (on macos)

Starting recording with the Time Profiler template. Launching process: .
Ctrl-C to stop the recording

test result: ok. 0 passed; 0 failed; 7 ignored; 1 measured; 0 filtered out; finished in 4.21s

Target app exited, ending recording...
Recording completed. Saving output file...
Output file saved as: cargo-flamegraph.trace
Error: unable to collapse generated profile data

Caused by:
    Invalid xml text from xctrace, which is not expected: UnterminatedEntity(72..77)

[djc]

I don't think this is actionable in the context of this project. The XML is generated by xctrace (I guess) and consumed by inferno.

[friedrich]

@djc symbols in the XML generated by xctrace are demangled by flamegraph without applying the necessary XML escaping, causing the generated XML to be invalid

[djc]

Pretty sure that part happens in inferno, though, not in flamegraph -- as I already explained.

[jarjk]

@friedrich you may want to ask the inferfno devs I understand

[friedrich]

The call to demangle_stream is clearly part of flamegraph: https://github.com/flamegraph-rs/flamegraph/blob/5c5129d8e1206b3be78b0a86cae12873d3587012/src/lib.rs#L533

Here is a fix that works for me: https://github.com/flamegraph-rs/flamegraph/commit/f82bc924e9e614d0b15203f01b9d2770ea74c373. I only tested it with xctrace, if other formats do not use XML it will break them.

[djc]

Ah, sorry, I forgot that demangling is done in this crate.

Pretty sure the other platforms do not use XML-based platforms, so your fix will need to be adapted. Additionally I'd prefer not to take on quick-xml as a dependency as it seems pretty heavyweight for what needs to be done here. Suggest using the xmlparser crate instead.

[friedrich]

quick-xml is already a dependency of flamegraph since it is used by inferno.

[djc]

Aahh, sorry, also didn't know about that. In that case, would be happy to review a PR.