# ANN: TraceCalls.jl, a debugging and profiling tool for Julia 0.6

**URL:** https://discourse.julialang.org/t/ann-tracecalls-jl-a-debugging-and-profiling-tool-for-julia-0-6/5283
**Category:** Community
**Tags:** package, announcement
**Created:** [August 8, 2017, 4:06pm UTC](https://discourse.julialang.org/t/ann-tracecalls-jl-a-debugging-and-profiling-tool-for-julia-0-6/5283 "2017-08-08T16:06:19Z")
**Posts on this page:** 1
**Showing post:** 4

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### Author: ![Per](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/per/32/10387_2.png) [@Per](https://discourse.julialang.org/u/Per)
#### Post date: [August 10, 2017, 6:23am UTC](https://discourse.julialang.org/t/ann-tracecalls-jl-a-debugging-and-profiling-tool-for-julia-0-6/5283/4 "2017-08-10T06:23:49Z")

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Thanks! This is exactly what [I’ve been looking for.](https://discourse.julialang.org/t/how-do-you-use-debuggers/4580/29)

I think, with `compare_past_trace` and just a few lines of code, I can have a function that takes two git commits and returns a set of tests that will work on one but fail on the other. (I prefer work with `runtest.jl` instead of trying out code at the REPL, so this fits perfectly into my workflow.)

Regarding mutable arguments: It’d be great if there were an option to recursively `copy` everything, always, but using a hash table so that multiple copies of the same object are only stored once. (RAM is cheap these days.)

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