pd: 📦 add a tracing event with cargo version

[cratelyn]

this adds a small tracing event including the version of pd that is running, before proceeding to handle the CLI command.

this should help operators identify when they are running a stale version of pd.

[hdevalence]

Maybe I'm missing something — this doesn't actually do what we want, right? That environment variable is set by Cargo when running Cargo, not when running pd...

[cratelyn]

Maybe I'm missing something — this doesn't actually do what we want, right? That environment variable is set by Cargo when running Cargo, not when running pd...

CARGO_PKG_VERSION — The full version of your package.

https://doc.rust-lang.org/cargo/reference/environment-variables.html#environment-variables-cargo-sets-for-crates

to my understanding, this would log versions like 0.68.1 or 0.68.2 etc., based on the version of the workspace/crate. this is set at compile-time like you describe, but that'd resolve to effectively let version = "1.2.3"; in the resulting binary.

in the interest of disambiguating whether a stale pd is running, that seems like at least a small step in the right direction. i'm happy to revert this though. what do you think @hdevalence?

[hdevalence]

My read of that page is that it's set by cargo, not embedded in the binary. But an easy way to test would be to run the binary ./target/release/pd and see.

[cratelyn]

My read of that page is that it's set by cargo, not embedded in the binary. But an easy way to test would be to run the binary ./target/release/pd and see.

i confirmed this works properly with a small test program:

; eza -T --ignore-glob target
.
├── Cargo.lock
├── Cargo.toml
└── src
   └── main.rs
; bat Cargo.toml | grep version
version = "0.1.0"
; ./target/debug/env-playground
0.1.0
; sed -i -e 's/0.1.0/1.2.3/' Cargo.toml
; cargo build --quiet
; ./target/debug/env-playground
1.2.3

[hdevalence]

Ah great! This is much simpler than I'd expected then, thanks for getting it merged in!