feat(composer): bake the dev build warning deadline in at build time

Composer defines COMPOSER_DEV_WARNING_TIME from its phar stub when the
compiled version is a commit hash rather than a tag, so the value exists
only in the build artifact. It was a todo!() in the PHP shim, leaving the
warning branch in Application::do_run unreachable.

A build script now derives it the way Compiler does, from git describe
and the HEAD commit date, and composer::COMPOSER_DEV_WARNING_TIME holds
the result as a Rust constant instead of a runtime-defined one.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

1 files changed, 55 insertions, 0 deletions

diff --git a/crates/shirabe/build.rs b/crates/shirabe/build.rs
new file mode 100644
index 00000000..22c8be58
--- /dev/null
+++ b/crates/shirabe/build.rs
@@ -0,0 +1,55 @@
+//! ref: composer/src/Composer/Compiler.php
+//!
+//! Generates a constant value of `composer::COMPOSER_DEV_WARNING_TIME`.
+
+fn git(repo_root: &std::path::Path, args: &[&str]) -> Option<String> {
+    let output = std::process::Command::new("git")
+        .args(args)
+        .current_dir(repo_root)
+        .output()
+        .ok()?;
+    if !output.status.success() {
+        return None;
+    }
+    Some(String::from_utf8(output.stdout).ok()?.trim().to_string())
+}
+
+fn main() {
+    println!("cargo::rerun-if-changed=build.rs");
+
+    let manifest_dir = std::env::var("CARGO_MANIFEST_DIR").unwrap();
+    let repo_root = std::path::Path::new(&manifest_dir)
+        .parent()
+        .unwrap()
+        .parent()
+        .unwrap();
+
+    if let Some(git_dir) = git(repo_root, &["rev-parse", "--git-dir"]) {
+        let git_dir = repo_root.join(git_dir);
+        for path in ["HEAD", "packed-refs", "refs/tags"] {
+            let path = git_dir.join(path);
+            if path.exists() {
+                println!("cargo::rerun-if-changed={}", path.display());
+            }
+        }
+    }
+
+    let dev_warning_time =
+        if git(repo_root, &["describe", "--tags", "--exact-match", "HEAD"]).is_some() {
+            None
+        } else {
+            git(repo_root, &["log", "-n1", "--pretty=%ct", "HEAD"])
+                .and_then(|date| date.parse::<i64>().ok())
+                .map(|date| date + 60 * 86400)
+        };
+
+    let out_dir = std::env::var("OUT_DIR").unwrap();
+    std::fs::write(
+        std::path::Path::new(&out_dir).join("dev_warning_time.rs"),
+        match dev_warning_time {
+            Some(time) => format!("Some({time})"),
+            None => "None".to_string(),
+        },
+    )
+    .unwrap();
+}