Rollup merge of #100040 - ChrisDenton:broken-pipe, r=davidtwco

Error on broken pipe but do not backtrace or ICE

Windows will report a broken pipe as a normal error which in turn `println!` will panic on. Currently this causes rustc to produce a backtrace and ICE. However, this is not a bug with rustc so a backtrace is overly verbose and ultimately unhelpful to the user.

Kind of fixes #98700. Although this is admittedly a bit of a hack because at panic time all we have is a string to inspect. On zulip it was suggested that libstd might someday provide a way to indicate a soft panic but that day isn't today.

1 files changed, 11 insertions, 0 deletions

diff --git a/compiler/rustc_driver/src/lib.rs b/compiler/rustc_driver/src/lib.rs
index 53ae913f94f..94639bf8e1e 100644
--- a/compiler/rustc_driver/src/lib.rs
+++ b/compiler/rustc_driver/src/lib.rs
@@ -1148,6 +1148,17 @@ static DEFAULT_HOOK: LazyLock<Box<dyn Fn(&panic::PanicInfo<'_>) + Sync + Send +
     LazyLock::new(|| {
         let hook = panic::take_hook();
         panic::set_hook(Box::new(|info| {
+            // If the error was caused by a broken pipe then this is not a bug.
+            // Write the error and return immediately. See #98700.
+            #[cfg(windows)]
+            if let Some(msg) = info.payload().downcast_ref::<String>() {
+                if msg.starts_with("failed printing to stdout: ") && msg.ends_with("(os error 232)")
+                {
+                    early_error_no_abort(ErrorOutputType::default(), &msg);
+                    return;
+                }
+            };
+
             // Invoke the default handler, which prints the actual panic message and optionally a backtrace
             (*DEFAULT_HOOK)(info);