From 65186e01285ba20e966e06f505f0e89e06694601 Mon Sep 17 00:00:00 2001
From: teapot4195 <huangalex409@gmail.com>
Date: Sat, 28 Jan 2023 15:20:27 -0500
Subject: [PATCH] Gracefully exit when --keep-stage used on clean source tree

---
 src/bootstrap/lib.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/bootstrap/lib.rs b/src/bootstrap/lib.rs
index d44b96cfb991e..522b3b7e851ff 100644
--- a/src/bootstrap/lib.rs
+++ b/src/bootstrap/lib.rs
@@ -1431,6 +1431,13 @@ impl Build {
             return Vec::new();
         }
 
+        if !stamp.exists() {
+            eprintln!(
+                "Warning: Unable to find the stamp file, did you try to keep a nonexistent build stage?"
+            );
+            crate::detail_exit(1);
+        }
+
         let mut paths = Vec::new();
         let contents = t!(fs::read(stamp), &stamp);
         // This is the method we use for extracting paths from the stamp file passed to us. See