build: update rerun-if conditions to watch .git/HEAD in colocated repo

Since .git/HEAD is less frequently updated, this should avoid unneeded
recompilation on test-only changes. This only applies to colocated repo.
For non-colocated repo, maybe we can watch src/ and ../lib/src files?

This also adds $NIX_JJ_GIT_HASH to reflect hash changes (and to not rerun
if no .git nor .jj directory exists.)
This commit is contained in:
Yuya Nishihara 2023-08-05 16:09:42 +09:00
parent aae14b24e0
commit 5e22e67584

View file

@ -12,11 +12,15 @@
// See the License for the specific language governing permissions and
// limitations under the License.
use std::path::Path;
use std::process::Command;
use std::str;
use cargo_metadata::MetadataCommand;
const GIT_HEAD_PATH: &str = "../.git/HEAD";
const JJ_OP_HEADS_PATH: &str = "../.jj/repo/op_heads/heads";
fn main() -> std::io::Result<()> {
let path = std::env::var("CARGO_MANIFEST_DIR").unwrap();
let meta = MetadataCommand::new()
@ -27,6 +31,16 @@ fn main() -> std::io::Result<()> {
let root = meta.root_package().unwrap();
let version = &root.version;
if Path::new(GIT_HEAD_PATH).exists() {
// In colocated repo, .git/HEAD should reflect the working-copy parent.
println!("cargo:rerun-if-changed={GIT_HEAD_PATH}");
} else if Path::new(JJ_OP_HEADS_PATH).exists() {
// op_heads changes when working-copy files are mutated, which is way more
// frequent than .git/HEAD.
println!("cargo:rerun-if-changed={JJ_OP_HEADS_PATH}");
}
println!("cargo:rerun-if-env-changed=NIX_JJ_GIT_HASH");
if let Some(git_hash) = get_git_hash() {
println!("cargo:rustc-env=JJ_VERSION={}-{}", version, git_hash);
} else {
@ -55,14 +69,12 @@ fn get_git_hash() -> Option<String> {
.output()
{
if output.status.success() {
println!("cargo:rerun-if-changed=../.jj/repo/op_heads/heads/");
return Some(String::from_utf8(output.stdout).unwrap());
}
}
if let Ok(output) = Command::new("git").args(["rev-parse", "HEAD"]).output() {
if output.status.success() {
println!("cargo:rerun-if-changed=../.git/HEAD");
let line = str::from_utf8(&output.stdout).unwrap();
return Some(line.trim_end().to_owned());
}