Avoid colons in trace file names

[cmyr]

This is not an allowed character in filenames on macOS.

cc @ckoehler, @teymour-aldridge , does this patch work for you?

( to test: check out this branch, then do cargo install --path ., and then use cargo instruments as before).

[ckoehler]

No, it actually doesn't, still can't open it. I noticed that the created file/dir is only 53 kB, whereas the output trace with a direct instruments call is 26 M or so. Incidentally, opening that one doesn't do what I expect it to, either, so I've just been running Instruments and opening my app manually, which works fine.

Thank you for looking into this, and sorry for adding to the noise; I'll bow out at this point. Feel free to ignore my comments.

[cmyr]

@ckoehler I'd still like to know what's going on. Is the crate you're profiling something you are able to share with me?

edit: or more to the point: does this problem occur for all crates?

[ckoehler]

Sorry, I cannot share it, it's internal. It's a Rocket REST API app. Behavior is the same with another internal project, a command line utility. A blind guess: maybe it's related to how you spawn the instruments process?

[cmyr]

I'd love to figure out if this is a problem with specific projects, or if it's a problem with your environment, if you have a chance to try cargo instruments on some publicly available code that would be helpful.

If you don't have anything handy, something I just tested was one of the examples in [piet]:(https://github.com/linebender/piet)

git checkout https://github.com/linebender/piet.git
cd piet/piet-common
cargo instruments -t time --example=mondrian --features png

does this work for you?

[cmyr]

In any case I'm going to merge this since I think it's still an improvement, and I'll move this discussion to #41