fix: check subprocess exit codes in Java tracer

_run_java_with_graceful_timeout() discarded the subprocess exit code in
both the no-timeout and timeout paths. If Maven/Gradle failed (compilation
error, OOM, etc.), the tracer silently continued with missing/stale data.

Now returns the exit code. Stage 1 (JFR profiling) warns on failure but
continues. Stage 2 (argument capture) raises RuntimeError since trace
data is essential for replay test generation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: mohamedashrraf222

codeflash/languages/java/tracer.py

@@ -17,17 +17,19 @@
 GRACEFUL_SHUTDOWN_WAIT = 5  # seconds to wait after SIGTERM before SIGKILL
 
 
-def _run_java_with_graceful_timeout(
-    java_command: list[str], env: dict[str, str], timeout: int, stage_name: str
-) -> None:
+def _run_java_with_graceful_timeout(java_command: list[str], env: dict[str, str], timeout: int, stage_name: str) -> int:
     """Run a Java command with graceful timeout handling.
 
     Sends SIGTERM first (allowing JFR dump and shutdown hooks to run),
     then SIGKILL if the process doesn't exit within GRACEFUL_SHUTDOWN_WAIT seconds.
+
+    Returns the process exit code, or -1 if the process was killed due to timeout.
     """
     if not timeout:
-        subprocess.run(java_command, env=env, check=False)
-        return
+        result = subprocess.run(java_command, env=env, check=False)
+        if result.returncode != 0:
+            logger.warning("%s exited with code %d", stage_name, result.returncode)
+        return result.returncode
 
     import signal
 
@@ -45,6 +47,11 @@ def _run_java_with_graceful_timeout(
             logger.warning("%s stage did not exit after SIGTERM, sending SIGKILL", stage_name)
             proc.kill()
             proc.wait()
+        return -1
+
+    if proc.returncode != 0:
+        logger.warning("%s exited with code %d", stage_name, proc.returncode)
+    return proc.returncode
 
 
 # --add-opens flags needed for Kryo serialization on Java 16+
@@ -78,21 +85,27 @@ def trace(
         jfr_file = trace_db_path.with_suffix(".jfr")
         trace_db_path.parent.mkdir(parents=True, exist_ok=True)
 
-        # Stage 1: JFR Profiling
+        # Stage 1: JFR Profiling (non-fatal — JFR data is supplementary)
         logger.info("Stage 1: Running JFR profiling...")
         jfr_env = self.build_jfr_env(jfr_file)
-        _run_java_with_graceful_timeout(java_command, jfr_env, timeout, "JFR profiling")
+        jfr_exit = _run_java_with_graceful_timeout(java_command, jfr_env, timeout, "JFR profiling")
 
-        if not jfr_file.exists():
+        if jfr_exit != 0:
+            logger.warning("JFR profiling failed (exit code %d), continuing without profiling data", jfr_exit)
+        elif not jfr_file.exists():
             logger.warning("JFR file was not created at %s", jfr_file)
 
-        # Stage 2: Argument Capture via Tracing Agent
+        # Stage 2: Argument Capture via Tracing Agent (fatal — trace data is essential)
         logger.info("Stage 2: Running argument capture...")
         config_path = self.create_tracer_config(
             trace_db_path, packages, project_root=project_root, max_function_count=max_function_count, timeout=timeout
         )
         agent_env = self.build_agent_env(config_path)
-        _run_java_with_graceful_timeout(java_command, agent_env, timeout, "Argument capture")
+        capture_exit = _run_java_with_graceful_timeout(java_command, agent_env, timeout, "Argument capture")
+
+        if capture_exit != 0:
+            msg = f"Argument capture failed with exit code {capture_exit} — cannot proceed without trace data"
+            raise RuntimeError(msg)
 
         if not trace_db_path.exists():
             logger.error("Trace database was not created at %s", trace_db_path)

tests/test_languages/test_java/test_tracer_exit_codes.py

@@ -0,0 +1,147 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+from unittest.mock import MagicMock, patch
+
+if TYPE_CHECKING:
+    from pathlib import Path
+
+import pytest
+
+from codeflash.languages.java.tracer import JavaTracer, _run_java_with_graceful_timeout
+
+
+class TestRunJavaWithGracefulTimeout:
+    def test_returns_zero_on_success(self) -> None:
+        mock_result = MagicMock()
+        mock_result.returncode = 0
+        with patch("codeflash.languages.java.tracer.subprocess.run", return_value=mock_result):
+            rc = _run_java_with_graceful_timeout(["java", "-version"], {}, 0, "test")
+        assert rc == 0
+
+    def test_returns_nonzero_on_failure(self) -> None:
+        mock_result = MagicMock()
+        mock_result.returncode = 1
+        with patch("codeflash.languages.java.tracer.subprocess.run", return_value=mock_result):
+            rc = _run_java_with_graceful_timeout(["java", "-version"], {}, 0, "test")
+        assert rc == 1
+
+    def test_returns_exit_code_137_oom_kill(self) -> None:
+        mock_result = MagicMock()
+        mock_result.returncode = 137
+        with patch("codeflash.languages.java.tracer.subprocess.run", return_value=mock_result):
+            rc = _run_java_with_graceful_timeout(["java", "-version"], {}, 0, "test")
+        assert rc == 137
+
+    def test_timeout_path_returns_zero_on_success(self) -> None:
+        mock_proc = MagicMock()
+        mock_proc.returncode = 0
+        with patch("codeflash.languages.java.tracer.subprocess.Popen", return_value=mock_proc):
+            rc = _run_java_with_graceful_timeout(["java", "-version"], {}, 60, "test")
+        assert rc == 0
+
+    def test_timeout_path_returns_nonzero_on_failure(self) -> None:
+        mock_proc = MagicMock()
+        mock_proc.returncode = 1
+        with patch("codeflash.languages.java.tracer.subprocess.Popen", return_value=mock_proc):
+            rc = _run_java_with_graceful_timeout(["java", "-version"], {}, 60, "test")
+        assert rc == 1
+
+    def test_timeout_returns_negative_one(self) -> None:
+        import subprocess
+
+        mock_proc = MagicMock()
+        # First wait() times out, SIGTERM wait succeeds
+        mock_proc.wait.side_effect = [
+            subprocess.TimeoutExpired(cmd="java", timeout=60),
+            None,  # SIGTERM wait succeeds
+        ]
+        with patch("codeflash.languages.java.tracer.subprocess.Popen", return_value=mock_proc):
+            rc = _run_java_with_graceful_timeout(["java", "-version"], {}, 60, "test")
+        assert rc == -1
+
+    def test_timeout_sends_sigterm_then_sigkill(self) -> None:
+        import signal
+        import subprocess
+
+        mock_proc = MagicMock()
+        # First wait() times out, SIGTERM wait also times out
+        mock_proc.wait.side_effect = [
+            subprocess.TimeoutExpired(cmd="java", timeout=60),
+            subprocess.TimeoutExpired(cmd="java", timeout=5),
+            None,
+        ]
+        with patch("codeflash.languages.java.tracer.subprocess.Popen", return_value=mock_proc):
+            rc = _run_java_with_graceful_timeout(["java", "-version"], {}, 60, "test")
+
+        assert rc == -1
+        mock_proc.send_signal.assert_called_once_with(signal.SIGTERM)
+        mock_proc.kill.assert_called_once()
+
+
+class TestJavaTracerExitCodeHandling:
+    def test_stage1_failure_continues(self, tmp_path: Path) -> None:
+        trace_db_path = (tmp_path / "trace.db").resolve()
+        tracer = JavaTracer()
+
+        # Stage 1 fails (exit code 1), Stage 2 succeeds (exit code 0)
+        exit_codes = iter([1, 0])
+
+        def mock_run_timeout(java_command: list[str], env: dict, timeout: int, stage_name: str) -> int:
+            rc = next(exit_codes)
+            if stage_name == "Argument capture":
+                trace_db_path.write_bytes(b"fake-db")
+            return rc
+
+        with (
+            patch("codeflash.languages.java.tracer._run_java_with_graceful_timeout", side_effect=mock_run_timeout),
+            patch.object(tracer, "build_jfr_env", return_value={}),
+            patch.object(tracer, "build_agent_env", return_value={}),
+            patch.object(tracer, "create_tracer_config", return_value=tmp_path / "config.json"),
+        ):
+            trace_db, _jfr_file = tracer.trace(
+                java_command=["java", "-cp", ".", "Main"], trace_db_path=trace_db_path, packages=["com.example"]
+            )
+        # Should complete despite Stage 1 failure
+        assert trace_db == trace_db_path
+
+    def test_stage2_failure_raises(self, tmp_path: Path) -> None:
+        trace_db_path = (tmp_path / "trace.db").resolve()
+        tracer = JavaTracer()
+
+        # Stage 1 succeeds (exit code 0), Stage 2 fails (exit code 1)
+        exit_codes = iter([0, 1])
+
+        def mock_run_timeout(java_command: list[str], env: dict, timeout: int, stage_name: str) -> int:
+            return next(exit_codes)
+
+        with (
+            patch("codeflash.languages.java.tracer._run_java_with_graceful_timeout", side_effect=mock_run_timeout),
+            patch.object(tracer, "build_jfr_env", return_value={}),
+            patch.object(tracer, "build_agent_env", return_value={}),
+            patch.object(tracer, "create_tracer_config", return_value=tmp_path / "config.json"),
+            pytest.raises(RuntimeError, match="Argument capture failed with exit code 1"),
+        ):
+            tracer.trace(
+                java_command=["java", "-cp", ".", "Main"], trace_db_path=trace_db_path, packages=["com.example"]
+            )
+
+    def test_both_stages_succeed(self, tmp_path: Path) -> None:
+        trace_db_path = (tmp_path / "trace.db").resolve()
+        tracer = JavaTracer()
+
+        def mock_run_timeout(java_command: list[str], env: dict, timeout: int, stage_name: str) -> int:
+            if stage_name == "Argument capture":
+                trace_db_path.write_bytes(b"fake-db")
+            return 0
+
+        with (
+            patch("codeflash.languages.java.tracer._run_java_with_graceful_timeout", side_effect=mock_run_timeout),
+            patch.object(tracer, "build_jfr_env", return_value={}),
+            patch.object(tracer, "build_agent_env", return_value={}),
+            patch.object(tracer, "create_tracer_config", return_value=tmp_path / "config.json"),
+        ):
+            trace_db, _jfr_file = tracer.trace(
+                java_command=["java", "-cp", ".", "Main"], trace_db_path=trace_db_path, packages=["com.example"]
+            )
+        assert trace_db == trace_db_path