# How to efficiently find the breaking dependency

**URL:** <https://discourse.julialang.org/t/how-to-efficiently-find-the-breaking-dependency/54497>\
**Category:** General Usage\
**Tags:** question, pkg\
**Created:** [February 2, 2021, 11:38pm UTC](https://discourse.julialang.org/t/how-to-efficiently-find-the-breaking-dependency/54497 "2021-02-02T23:38:18Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![mannydepresso](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mannydepresso/32/18177_2.png) [@mannydepresso](https://discourse.julialang.org/u/mannydepresso)\
**Post date:** [February 2, 2021, 11:38pm UTC](https://discourse.julialang.org/t/how-to-efficiently-find-the-breaking-dependency/54497/1 "2021-02-02T23:38:18Z")

</div>

Hi!  
Suppose I have a package `A` that I wrote myself, and I add it to a separate project environment `B`. I test `A` in `A` by running

```julia
using Pkg
Pkg.activate("A/")
Pkg.test("A")

```

and the tests fail. However, if I do the same thing but instead I activate `B/` the tests run to completion.

Some of the dependency versions in `B/Manifest.toml` are different than in `A/` so I’m lead to believe that it’s a version difference that’s causing the difference.

This bring me to my question:

**TL;DR** How do I bisect the difference between two `Manifest.toml`’s _efficiently_ to see which dependency version breaks one package/environment.