How to use Cargo patch for dependency overrides

Add a [patch] section to your Cargo.toml file to override a dependency with a local path or git repository. This tells Cargo to ignore the version on crates.io and use your specified source instead.

[patch.crates-io]
serde = { path = "../my-local-serde" }
# or
# serde = { git = "https://github.com/your-org/serde", branch = "main" }

Run cargo build to apply the override. Cargo will now compile your project using the patched version of serde instead of the one from crates.io.

Cargo patch lets you swap a standard library dependency with your own custom version. This is useful when you need to test a fix or a new feature before it is officially released. Think of it like replacing a standard part in a car with a custom-made one to see if it works better.