grok-build-upstream-mirror/crates/build/xai-proto-build/src/find_protoc.rs
grokkybara[bot] c68e39f604 Publish harness and TUI open-source
initial sync from the monorepo
2026-07-16 06:46:02 +01:00

93 lines
3.3 KiB
Rust

use anyhow::{Context, bail};
use std::env;
use std::path::{Path, PathBuf};
use std::process::Command;
fn check_protoc_good(protoc: &Path) -> anyhow::Result<()> {
let output = Command::new(protoc)
.arg("--version")
.output()
.context("Failed to execute protoc")?;
if !output.status.success() {
let stdout = String::from_utf8_lossy(&output.stdout);
let stderr = String::from_utf8_lossy(&output.stderr);
bail!(
"protoc --version failed, likely dotslash is missing; \
try `cargo install dotslash`; stdout: {stdout:?}, stderr: {stderr:?}"
);
}
Ok(())
}
fn is_github_actions() -> bool {
env::var_os("GITHUB_ACTIONS").is_some()
}
/// Find `protoc` command.
///
/// Search order:
/// 1. `$PROTOC` environment variable (set by Bazel `build_script_env` or user override)
/// 2. `bin/protoc` walking up parent directories (dotslash wrapper for local dev)
/// 3. `protoc` on `$PATH` (system install or other tooling)
///
/// When `bin/protoc` exists but fails to execute (e.g. the dotslash wrapper running
/// in Bazel remote execution where `dotslash` is not installed), the error is not fatal —
/// we fall through to the PATH-based lookup instead.
///
/// Returns `Ok(None)` if not found and not in a strict environment (GitHub Actions).
pub fn find_protoc() -> anyhow::Result<Option<PathBuf>> {
// 1. Check the PROTOC env var first. This is the standard override used by prost-build
// and is set by Bazel cargo_build_script build_script_env to point at a hermetic
// protoc binary instead of the dotslash wrapper.
if let Ok(protoc_env) = env::var("PROTOC") {
let protoc = PathBuf::from(&protoc_env);
if protoc.try_exists()? {
check_protoc_good(&protoc)?;
return Ok(Some(protoc));
}
}
// 2. Walk up directories looking for bin/protoc (dotslash wrapper).
let cwd = env::current_dir()?;
let mut dir = cwd.clone();
let mut dir_rel = PathBuf::new();
loop {
// Return relative path to make build more deterministic.
let protoc = dir_rel.join("bin/protoc");
if protoc.try_exists()? {
match check_protoc_good(&protoc) {
Ok(()) => return Ok(Some(protoc)),
Err(e) => {
// bin/protoc exists but can't execute — likely the dotslash wrapper
// in an environment without dotslash (e.g. Bazel remote execution).
// Fall through to PATH-based lookup below.
eprintln!(
"bin/protoc found at `{}` but failed to execute: {e:#}; \
trying protoc from PATH as fallback",
protoc.display()
);
break;
}
}
}
if !dir.pop() {
break;
}
dir_rel.push("..");
}
// 3. Try protoc from PATH (system install or other tooling).
if check_protoc_good(Path::new("protoc")).is_ok() {
return Ok(Some(PathBuf::from("protoc")));
}
// 4. Not found anywhere.
if is_github_actions() {
return Err(anyhow::anyhow!(
"`protoc` not found (checked $PROTOC env, bin/protoc, and PATH)"
));
}
eprintln!("`protoc` not found; likely it is missing in docker image");
Ok(None)
}