1 files changed, 30 insertions, 5 deletions
diff --git a/.run/src/lib.rs b/.run/src/lib.rs
index cff606a..b17a61f 100644
--- a/.run/src/lib.rs
+++ b/.run/src/lib.rs
@@ -3,6 +3,8 @@ pub mod verify;
 
 use colored::Colorize;
 
+use std::io::IsTerminal as _;
+
 #[macro_export]
 macro_rules! run_cmd {
     ($fmt:literal, $($arg:tt)*) => {
@@ -201,7 +203,15 @@ pub fn run_cmd_capture_with_dir(
     let exit_code = output.status.code().unwrap_or(1);
     let stderr = String::from_utf8_lossy(&output.stderr).to_string();
     let stdout = String::from_utf8_lossy(&output.stdout).to_string();
-    let combined = if stderr.is_empty() { stdout } else { stderr };
+    // Keep both streams so a failure is never hidden: when stderr carries
+    // warnings, the real failure details (e.g. the failing test name and
+    // assertion diff) usually live on stdout and must not be dropped.
+    let combined = match (stdout.trim().is_empty(), stderr.trim().is_empty()) {
+        (false, false) => format!("{stdout}\n{stderr}"),
+        (false, true) => stdout,
+        (true, false) => stderr,
+        (true, true) => stdout,
+    };
 
     if exit_code == 0 {
         Ok(combined)
@@ -275,15 +285,30 @@ pub fn run_parallel(phase: &str, tasks: Vec<(String, String, String)>) -> Result
             if first_exit_code == 0 {
                 first_exit_code = code;
             }
-            pb.println(format!(
+            let msg = format!(
                 "{}: {} failed (exit code {})",
                 "error".bright_red().bold(),
                 labels[i],
                 code,
-            ));
+            );
+            let mut lines = Vec::new();
             if !output.is_empty() {
-                for line in output.lines() {
-                    pb.println(format!("  {line}"));
+                lines.extend(output.lines().map(|l| format!("  {l}")));
+            }
+            if std::io::stdout().is_terminal() {
+                // On a TTY, render errors through the progress bar so they
+                // appear above it.
+                pb.println(&msg);
+                for line in &lines {
+                    pb.println(line);
+                }
+            } else {
+                // On a non-TTY (CI, piped output), `ProgressBar::println` can
+                // be swallowed, hiding the failure. Emit to plain stdout so the
+                // failure is always visible.
+                println!("{msg}");
+                for line in &lines {
+                    println!("{line}");
                 }
             }
         }