From c9a827d6fe66f95c8fca34cb8649151d5a668f06 Mon Sep 17 00:00:00 2001
From: Adam Mohammed A Latif <latifkasuli@gmail.com>
Date: Wed, 3 Jun 2026 13:39:25 +0000
Subject: [PATCH] lean_compiler: avoid duplicate compile-and-run output

---
 crates/lean_compiler/src/lib.rs               |  1 -
 .../tests/try_compile_and_run_output.rs       | 52 +++++++++++++++++++
 2 files changed, 52 insertions(+), 1 deletion(-)
 create mode 100644 crates/lean_compiler/tests/try_compile_and_run_output.rs

diff --git a/crates/lean_compiler/src/lib.rs b/crates/lean_compiler/src/lib.rs
index 3564cfaa..b339f4e7 100644
--- a/crates/lean_compiler/src/lib.rs
+++ b/crates/lean_compiler/src/lib.rs
@@ -180,7 +180,6 @@ pub fn try_compile_and_run(
     let bytecode = try_compile_program(input)?;
     let witness = ExecutionWitness::default();
     let result = try_execute_bytecode(&bytecode, public_input, &witness, profiler)?;
-    println!("{}", result.metadata.display());
     Ok(result.metadata.display())
 }
 
diff --git a/crates/lean_compiler/tests/try_compile_and_run_output.rs b/crates/lean_compiler/tests/try_compile_and_run_output.rs
new file mode 100644
index 00000000..8af8f957
--- /dev/null
+++ b/crates/lean_compiler/tests/try_compile_and_run_output.rs
@@ -0,0 +1,52 @@
+use std::process::Command;
+
+use backend::PrimeCharacteristicRing;
+use lean_compiler::{ProgramSource, try_compile_and_run};
+use lean_vm::{DIGEST_LEN, F};
+
+const CHILD_TEST: &str = "child_calls_try_compile_and_run";
+const CHILD_ENV: &str = "LEAN_COMPILER_TRY_COMPILE_AND_RUN_CHILD";
+
+#[test]
+fn try_compile_and_run_does_not_print_summary() {
+    // Re-exec this test binary so stdout capture stays process-local and does not
+    // depend on global test harness state. `--exact` avoids recursively running
+    // this parent test in the child process.
+    let output = Command::new(std::env::current_exe().unwrap())
+        .arg("--exact")
+        .arg(CHILD_TEST)
+        .arg("--nocapture")
+        .env(CHILD_ENV, "1")
+        .output()
+        .unwrap();
+
+    assert!(
+        output.status.success(),
+        "child test failed\nstdout:\n{}\nstderr:\n{}",
+        String::from_utf8_lossy(&output.stdout),
+        String::from_utf8_lossy(&output.stderr),
+    );
+
+    let stdout = String::from_utf8_lossy(&output.stdout);
+    assert!(
+        !stdout.contains("STATS"),
+        "try_compile_and_run unexpectedly printed the execution summary:\n{stdout}"
+    );
+}
+
+#[test]
+fn child_calls_try_compile_and_run() {
+    // This test only does real work in the child process spawned above.
+    if std::env::var_os(CHILD_ENV).is_none() {
+        return;
+    }
+
+    let summary = try_compile_and_run(
+        &ProgramSource::Raw("def main():\n    return\n".to_string()),
+        &[F::ZERO; DIGEST_LEN],
+        false,
+    )
+    .unwrap();
+
+    assert!(summary.contains("STATS"));
+}