# What's the meaning of project\_hash in Manifest.toml?

**URL:** https://discourse.julialang.org/t/whats-the-meaning-of-project-hash-in-manifest-toml/97923
**Category:** General Usage
**Tags:** pkg
**Created:** [April 26, 2023, 2:30am UTC](https://discourse.julialang.org/t/whats-the-meaning-of-project-hash-in-manifest-toml/97923 "2023-04-26T02:30:51Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![ettersi](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ettersi/32/6829_2.png) [@ettersi](https://discourse.julialang.org/u/ettersi)
#### Post date: [April 26, 2023, 2:30am UTC](https://discourse.julialang.org/t/whats-the-meaning-of-project-hash-in-manifest-toml/97923/1 "2023-04-26T02:30:52Z")

</div>

Let’s create a new environment in Julia 1.8.5:

```julia
(@v1.8) pkg> activate .
  Activating new project at `/private/tmp/test`

(test) pkg> add Example
    Updating registry at `~/.julia/registries/General.toml`
   Resolving package versions...
    Updating `/private/tmp/test/Project.toml`
  [7876af07] + Example v0.5.3
    Updating `/private/tmp/test/Manifest.toml`
  [7876af07] + Example v0.5.3

```

The Manifest.toml file then looks as follows:

```julia
# This file is machine-generated - editing it directly is not advised

julia_version = "1.8.5"
manifest_format = "2.0"
project_hash = "2ca1c6c58cb30e79e021fb54e5626c96d05d5fdc" # <- What's this?

[[deps.Example]]
git-tree-sha1 = "46e44e869b4d90b96bd8ed1fdcf32244fddfb6cc"
uuid = "7876af07-990d-54b4-ab0e-23690620f79a"
version = "0.5.3"

```

My question is, what is the meaning of `project_hash`? Is it a hash of `Manifest.toml`? Or maybe `Project.toml`? Or something else entirely? Searching for `project_hash` on [https://pkgdocs.julialang.org/](https://pkgdocs.julialang.org/) didn’t yield any results…

---

<div class="post-metadata">

### Author: ![GunnarFarneback](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/gunnarfarneback/32/1827_2.png) [@GunnarFarneback](https://discourse.julialang.org/u/GunnarFarneback)
#### Post date: [April 26, 2023, 5:43am UTC](https://discourse.julialang.org/t/whats-the-meaning-of-project-hash-in-manifest-toml/97923/2 "2023-04-26T05:43:28Z")

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It’s computed here: [Pkg.jl/Types.jl at master · JuliaLang/Pkg.jl · GitHub](https://github.com/JuliaLang/Pkg.jl/blob/master/src/Types.jl#L257-L263)

So it’s a content hash of the `deps` and `compat` sections of `Project.toml`. Judging from the comment this is used to determine whether the Manifest is up to date with the Project.