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Expose rust-version through env var #10713

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Merged
merged 1 commit into from
Jun 6, 2022
Merged

Expose rust-version through env var #10713

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4 changes: 4 additions & 0 deletions src/cargo/core/compiler/compilation.rs
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Expand Up @@ -347,6 +347,10 @@ impl<'cfg> Compilation<'cfg> {
metadata.license_file.as_ref().unwrap_or(&String::new()),
)
.env("CARGO_PKG_AUTHORS", &pkg.authors().join(":"))
.env(
"CARGO_PKG_RUST_VERSION",
&pkg.rust_version().unwrap_or(&String::new()),
)
.cwd(pkg.root());

// Apply any environment variables from the config
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3 changes: 3 additions & 0 deletions src/doc/src/reference/environment-variables.md
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Expand Up @@ -214,6 +214,9 @@ corresponding environment variable is set to the empty string, `""`.
* `CARGO_PKG_REPOSITORY` — The repository from the manifest of your package.
* `CARGO_PKG_LICENSE` — The license from the manifest of your package.
* `CARGO_PKG_LICENSE_FILE` — The license file from the manifest of your package.
* `CARGO_PKG_RUST_VERSION` — The Rust version from the manifest of your package.
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@epage epage May 29, 2022

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The thing going through my head is the question: "what principle governs us exposing the manifest as environment variables?".

For myself, exposing CARGO_PKG_RUST_VERSION feels very arbitrary from a cargo-design perspective. Why this field and not many of the others?

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@flip1995 flip1995 May 29, 2022 •
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Many of the other fields are already exposed. Like the version field is even exposed through 4 or 5 env vars. Most package metadata is exposed. I think this makes it more consistent.

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@ghost ghost May 30, 2022

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Also see #8758 where CARGO_PRIMARY_PACKAGE was added "primarily for Clippy".

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@epage epage May 30, 2022

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Many of the other fields are already exposed. Like the version field is even exposed through 4 or 5 env vars. Most package metadata is exposed. I think this makes it more consistent.

Except for CARGO_PRIMARY_PACKAGE , those all look targeted at the code being built, either so a crate can access its own metadata or build.rs / test purposes.

Also see #8758 where CARGO_PRIMARY_PACKAGE was added "primarily for Clippy".

Thanks for pointing out precedence on this. I am still interested in seeing if there is an answer to my question or if there is interest in creating an answer to my question. Until that time, I am not comfortable merging this though maybe others of the cargo team would be.

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@flip1995 flip1995 May 30, 2022

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I'm good with waiting on other team members. Just wanted to bring this up through a PR again, because my question some time ago on Zulip didn't get any replies 😅

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@joshtriplett joshtriplett May 31, 2022 •
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Suggested change
* `CARGO_PKG_RUST_VERSION` — The Rust version from the manifest of your package.
* `CARGO_PKG_RUST_VERSION` — The Rust version from the manifest of your package. Note that this is the minimum Rust version supported by the package, not the current Rust version.

(People regularly want Rust compiler version information, so I want to make sure people don't think this is the thing they're looking for for that.)

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@epage epage May 31, 2022

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We discussed this in the cargo team meeting and we have no guiding principle on what env variables should exist and are intending to be responsive to what different teams needs are. I'm fine merging this after the documentation gets improved.

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@epage epage May 31, 2022 •
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I'm surprised we don't link any of these fields to their manifest field's documentation. That would also be a natural way to clarify what this is intending to contain

Note that this is the minimum Rust version supported by the package, not the
current Rust version.
* `CARGO_CRATE_NAME` — The name of the crate that is currently being compiled.
* `CARGO_BIN_NAME` — The name of the binary that is currently being compiled (if it is a binary). This name does not include any file extension, such as `.exe`.
* `OUT_DIR` — If the package has a build script, this is set to the folder where the build
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3 changes: 3 additions & 0 deletions tests/testsuite/build.rs
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Expand Up @@ -1314,6 +1314,7 @@ fn crate_env_vars() {
authors = ["[email protected]"]
license = "MIT OR Apache-2.0"
license-file = "license.txt"
rust-version = "1.61.0"

[[bin]]
name = "foo-bar"
Expand All @@ -1338,6 +1339,7 @@ fn crate_env_vars() {
static LICENSE: &'static str = env!("CARGO_PKG_LICENSE");
static LICENSE_FILE: &'static str = env!("CARGO_PKG_LICENSE_FILE");
static DESCRIPTION: &'static str = env!("CARGO_PKG_DESCRIPTION");
static RUST_VERSION: &'static str = env!("CARGO_PKG_RUST_VERSION");
static BIN_NAME: &'static str = env!("CARGO_BIN_NAME");
static CRATE_NAME: &'static str = env!("CARGO_CRATE_NAME");

Expand All @@ -1356,6 +1358,7 @@ fn crate_env_vars() {
assert_eq!("MIT OR Apache-2.0", LICENSE);
assert_eq!("license.txt", LICENSE_FILE);
assert_eq!("This is foo", DESCRIPTION);
assert_eq!("1.61.0", RUST_VERSION);
let s = format!("{}.{}.{}-{}", VERSION_MAJOR,
VERSION_MINOR, VERSION_PATCH, VERSION_PRE);
assert_eq!(s, VERSION);
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