From 28b7e6abff37d280f7077ed1f362ed7954753c75 Mon Sep 17 00:00:00 2001
From: Jynn Nelson <jyn.nelson@redjack.com>
Date: Fri, 31 Mar 2023 07:15:42 -0400
Subject: [PATCH] Replace any existing `build/host` symlink

This has two advantages:
1. If `build.build` changes between runs, the symlink is no longer
   silently wrong.
2. If the entire build directory is moved, the symlink is no longer
   broken because it points to the wrong absolute path.
---
 src/bootstrap/lib.rs | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/src/bootstrap/lib.rs b/src/bootstrap/lib.rs
index 2ffad594fc7ac..e3f3ab5243e2c 100644
--- a/src/bootstrap/lib.rs
+++ b/src/bootstrap/lib.rs
@@ -21,7 +21,6 @@ use std::collections::{HashMap, HashSet};
 use std::env;
 use std::fs::{self, File};
 use std::io;
-use std::io::ErrorKind;
 use std::path::{Path, PathBuf};
 use std::process::{Command, Stdio};
 use std::str;
@@ -505,16 +504,18 @@ impl Build {
         let build_triple = build.out.join(&build.build.triple);
         t!(fs::create_dir_all(&build_triple));
         let host = build.out.join("host");
-        if let Err(e) = symlink_dir(&build.config, &build_triple, &host) {
-            if e.kind() != ErrorKind::AlreadyExists {
-                panic!(
-                    "symlink_dir({} => {}) failed with {}",
-                    host.display(),
-                    build_triple.display(),
-                    e
-                );
-            }
-        }
+        if host.is_symlink() {
+            // Left over from a previous build; overwrite it.
+            // This matters if `build.build` has changed between invocations.
+            #[cfg(windows)]
+            t!(fs::remove_dir(&host));
+            #[cfg(not(windows))]
+            t!(fs::remove_file(&host));
+        }
+        t!(
+            symlink_dir(&build.config, &build_triple, &host),
+            format!("symlink_dir({} => {}) failed", host.display(), build_triple.display())
+        );
 
         build
     }