include git rev when installed from crates.io

Author: Firestar99

crates/cargo-gpu/Cargo.toml

@@ -23,6 +23,10 @@ serde_json.workspace = true
 semver.workspace = true
 dunce.workspace = true
 
+[build-dependencies]
+serde.workspace = true
+serde_json.workspace = true
+
 [dev-dependencies]
 cargo-gpu-install = { workspace = true, features = ["test"] }
 test-log.workspace = true

crates/cargo-gpu/build.rs

@@ -1,9 +1,26 @@
 //! cargo-gpu build script.
 
+use serde_json::Value;
 use std::ffi::OsStr;
 use std::path::PathBuf;
 
 fn main() {
+    compute_version_extra();
+}
+
+fn compute_version_extra() {
+    let extra = version_crates_io()
+        .or_else(version_git)
+        .unwrap_or(String::from(" installed from unknown source"));
+
+    std::fs::write(
+        PathBuf::from(std::env::var("OUT_DIR").unwrap()).join("version_extra"),
+        extra,
+    )
+    .unwrap();
+}
+
+fn version_git() -> Option<String> {
     if let Some(git_directory) = invoke_git(["rev-parse", "--git-dir"]) {
         println!("cargo:rerun-if-changed={git_directory}/HEAD");
     }
@@ -17,20 +34,15 @@ fn main() {
         "HEAD",
     ]);
 
-    let extra = if let Some(git_rev) = git_rev
+    if let Some(rev) = git_rev
         && let Some(git_date) = git_date
     {
-        let git_rev = git_rev.get(..8).unwrap_or(&git_rev);
+        let rev = rev.get(..8).unwrap_or(&rev);
         let git_date = git_date.strip_suffix("\n").unwrap_or(&git_date);
-        format!(" ({git_rev} {git_date})")
+        Some(format!(" installed from repo at rev {rev} ({git_date})"))
     } else {
-        " (installed from crates.io)".into()
-    };
-    std::fs::write(
-        PathBuf::from(std::env::var("OUT_DIR").unwrap()).join("version_extra"),
-        extra,
-    )
-    .unwrap();
+        None
+    }
 }
 
 fn invoke_git<I, S>(args: I) -> Option<String>
@@ -44,3 +56,15 @@ where
         .ok()
         .and_then(|output| String::from_utf8(output.stdout).ok())
 }
+
+/// `cargo package` adds the `.cargo_vcs_info.json` file on it's own, let's just use that to resolve the rev
+fn version_crates_io() -> Option<String> {
+    let json = std::fs::read_to_string(
+        PathBuf::from(env!("CARGO_MANIFEST_DIR")).join(".cargo_vcs_info.json"),
+    )
+    .ok()?;
+    let value = serde_json::from_str::<Value>(&json).ok()?;
+    let rev = value.get("git")?.get("sha1")?.as_str()?;
+    let rev = rev.get(..8).unwrap_or(rev);
+    Some(format!(" installed from crates.io (rev {rev})"))
+}