5e6685c689
The BAT_SYNTAXES environment variable is injected during Nix builds and points to the build result of //third_party/bat_syntaxes, which is included in the cheddar binary. During development this is a bit annoying: Opening a Nix shell will set the right variable, but it will also mess with the Cargo environment in ways that make it annoying to use (*and* require a pre-build of all dependencies as required by naersk). For an easier development flow, this adds a build script that automatically runs Nix, fetches the path to the syntax set and sets the environment variable. It is a no-op if the variable is already set. This makes for a smoother development experience when working on cheddar in a depot checkout. Change-Id: Ib5435518897e3443247edd9f362821c0b9ff756b Reviewed-on: https://cl.tvl.fyi/c/depot/+/3081 Tested-by: BuildkiteCI Reviewed-by: flokli <flokli@flokli.de>
50 lines
1.7 KiB
Rust
50 lines
1.7 KiB
Rust
//! Build script that can be used outside of Nix builds to inject the
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//! BAT_SYNTAXES variable when building in development mode.
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//!
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//! Note that this script assumes that cheddar is in a checkout of the
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//! TVL depot.
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use std::process::Command;
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static BAT_SYNTAXES: &str = "BAT_SYNTAXES";
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static ERROR_MESSAGE: &str = r#"Failed to build syntax set.
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When building during development, cheddar expects to be in a checkout
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of the TVL depot. This is required to automatically build the syntax
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highlighting files that are needed at compile time.
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As cheddar can not automatically detect the location of the syntax
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files, you must set the `BAT_SYNTAXES` environment variable to the
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right path.
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The expected syntax files are at //third_party/bat_syntaxes in the
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depot."#;
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fn main() {
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// Do nothing if the variable is already set (e.g. via Nix)
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if let Ok(_) = std::env::var(BAT_SYNTAXES) {
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return;
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}
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// Otherwise ask Nix to build it and inject the result.
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let output = Command::new("nix-build")
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.arg("-A").arg("third_party.bat_syntaxes")
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// ... assuming cheddar is at //tools/cheddar ...
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.arg("../..")
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.output()
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.expect(ERROR_MESSAGE);
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if !output.status.success() {
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eprintln!("{}\nNix output: {}", ERROR_MESSAGE, String::from_utf8_lossy(&output.stderr));
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return;
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}
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let out_path = String::from_utf8(output.stdout)
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.expect("Nix returned invalid output after building syntax set");
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// Return an instruction to Cargo that will set the environment
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// variale during rustc calls.
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//
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// https://doc.rust-lang.org/cargo/reference/build-scripts.html#cargorustc-envvarvalue
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println!("cargo:rustc-env={}={}", BAT_SYNTAXES, out_path.trim());
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}
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