From cd3bc5f08239a30169e6b5e2e89f4dc88aa26db2 Mon Sep 17 00:00:00 2001
From: Noratrieb <48135649+Noratrieb@users.noreply.github.com>
Date: Mon, 23 Jun 2025 21:01:08 +0200
Subject: [PATCH] Fix hang in --print=file-names in bootstrap

In an interactive context, the subprocess inherited a real tty stdin,
which lead it it waiting for something to happen, even though nothing
happened. By explicitly passing null as stdin we make sure an empty file
is passed, which achieves the desired behavior.

(cherry picked from commit 3003050d473abd13d56c7e7966b971bd7443194f)
---
 src/bootstrap/src/core/builder/cargo.rs | 1 +
 src/bootstrap/src/utils/exec.rs         | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/src/bootstrap/src/core/builder/cargo.rs b/src/bootstrap/src/core/builder/cargo.rs
index 0e3c3aaee0ff..99044e2a2530 100644
--- a/src/bootstrap/src/core/builder/cargo.rs
+++ b/src/bootstrap/src/core/builder/cargo.rs
@@ -683,6 +683,7 @@ fn cargo(
                         .arg("--print=file-names")
                         .arg("--crate-type=proc-macro")
                         .arg("-")
+                        .stdin(std::process::Stdio::null())
                         .run_capture(self)
                         .stderr();
 
diff --git a/src/bootstrap/src/utils/exec.rs b/src/bootstrap/src/utils/exec.rs
index eb9802bf2e1b..78b28ac18282 100644
--- a/src/bootstrap/src/utils/exec.rs
+++ b/src/bootstrap/src/utils/exec.rs
@@ -119,6 +119,11 @@ pub fn current_dir<P: AsRef<Path>>(&mut self, dir: P) -> &mut Self {
         self
     }
 
+    pub fn stdin(&mut self, stdin: std::process::Stdio) -> &mut Self {
+        self.command.stdin(stdin);
+        self
+    }
+
     #[must_use]
     pub fn delay_failure(self) -> Self {
         Self { failure_behavior: BehaviorOnFailure::DelayFail, ..self }