Quick, automated Cargo dependencies

2020.01.12 Rust

For a long time, I have been adding cargo dependencies one by one, using crates.io to copy and paste a version string to copy and paste into Cargo.toml.

Recently, however, I found a quick and simple solution to sidestep this unnecessary effort, using the excellent cargo-edit.

Once installed with

cargo install cargo-edit

...cargo edit installs cargo commands, including cargo upgrade, which handily upgrades all of the dependencies in a Cargo.toml. This is nice on its own, and something I was looking for for a while anyway.

EDIT: previously missing the blindingly obvious, cargo-edit also provides cargo add <crate> which achieves exactly the same thing as below.

A nice side effect of this beautiful command, however, is that you can add a new dependency, e.g. dirs, with an "any"/* dependency:

[dependencies]
aocf = {version = "0.1.1", path = ".."}
chrono = "0.4.10"
docopt = "1.1.0"
dirs = "*"
failure = "0.1.6"
serde = "1.0.104"
serde_derive = "1.0.104"
tempfile = "3.1.0"
toml = "0.5.5"

And then after running cargo upgrade, you are magically left with the latest version of the crate from crates.io:

[dependencies]
aocf = {version = "0.1.1", path = ".."}
chrono = "0.4.10"
docopt = "1.1.0"
dirs = "2.0.2"
failure = "0.1.6"
serde = "1.0.104"
serde_derive = "1.0.104"
tempfile = "3.1.0"
toml = "0.5.5"

Clearly this works best if you keep all of your other dependencies up to date, but I think this is either a) good practice, or b) you could always use git add -p.

Alternatively, in this case, you can use:

cargo upgrade dirs

...and it will only upgrade the dirs dependency.