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use std::path::PathBuf;
fn main() {
// If the env var changes, we must re-run to pick up a different config.
println!("cargo:rerun-if-env-changed=CANIC_CONFIG_PATH");
// Path to this crate at build time.
let manifest_dir =
PathBuf::from(std::env::var("CARGO_MANIFEST_DIR").expect("CARGO_MANIFEST_DIR must be set"));
// Repo-default config location (works in workspace builds).
// NOTE: This path will NOT exist in `cargo package` / `cargo publish` builds because
// Cargo builds from a staged directory under target/package/ that does not include
// workspace siblings.
let repo_cfg = manifest_dir.join("../canisters/canic.toml");
// Determine the config path:
// - If CANIC_CONFIG_PATH is set, it is authoritative (relative paths resolved from the crate).
// - Otherwise, fall back to the repo default.
let env_cfg = std::env::var("CANIC_CONFIG_PATH").ok();
let cfg_path = env_cfg.as_ref().map_or(repo_cfg, |val| {
let path = PathBuf::from(val);
if path.is_relative() {
manifest_dir.join(path)
} else {
path
}
});
// If the user explicitly set CANIC_CONFIG_PATH, missing config is a hard error.
if env_cfg.is_some() {
assert!(
cfg_path.exists(),
"Missing Canic config at {}",
cfg_path.display()
);
} else if !cfg_path.exists() {
// Packaged builds won't include ../canisters. Skip build-time validation.
// This keeps `cargo package` / `cargo publish` working.
//
// IMPORTANT: Any code that consumes CANIC_CONFIG_PATH must tolerate it being unset
// in packaged builds (e.g., via option_env!).
println!(
"cargo:warning=CANIC_CONFIG_PATH not set and default config not found at {}; \
skipping config validation (likely a packaged build)",
cfg_path.display()
);
return;
}
// Re-run if the config changes.
println!("cargo:rerun-if-changed={}", cfg_path.display());
if let Some(parent) = cfg_path.parent() {
// Directory watch is not recursive, but it helps in common cases (file replaced/renamed).
println!("cargo:rerun-if-changed={}", parent.display());
}
// Validate the config early so failures are caught at build time.
let config_str = std::fs::read_to_string(&cfg_path).expect("read canic config for validation");
canic_core::config::Config::init_from_toml(&config_str).expect("Invalid Canic config");
// Export the canonicalized path for compile-time use.
println!(
"cargo:rustc-env=CANIC_CONFIG_PATH={}",
cfg_path
.canonicalize()
.expect("canonicalize canic config path")
.display()
);
}