From ab76a0bf3bff33fe35570d345cffa0a50545f3f5 Mon Sep 17 00:00:00 2001
From: Pietro Albini <pietro.albini@ferrous-systems.com>
Date: Mon, 13 Nov 2023 11:22:55 +0100
Subject: [PATCH] respect rust-lang/rust's omit-git-hash

The config.toml file in rust-lang/rust has the omit-git-hash option,
which prevents git information from being embedded into binaries. This
works for most tools, as they rely on the git information provided by
bootstrap through environment variables.

Cargo does its own git detection in its build script though, which
didn't adhere to to that option. This changes that by skipping git
detection whenever bootstrap signals the option is enabled.
---
 build.rs | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/build.rs b/build.rs
index 752221f8cdc..97678ed1bab 100644
--- a/build.rs
+++ b/build.rs
@@ -50,6 +50,14 @@ fn commit_info() {
     if !Path::new(".git").exists() {
         return;
     }
+
+    // Var set by bootstrap whenever omit-git-hash is enabled in rust-lang/rust's config.toml.
+    println!("cargo:rerun-if-env-changed=CFG_OMIT_GIT_HASH");
+    #[allow(clippy::disallowed_methods)]
+    if std::env::var_os("CFG_OMIT_GIT_HASH").is_some() {
+        return;
+    }
+
     let output = match Command::new("git")
         .arg("log")
         .arg("-1")