fix: ensure python3 available in OpenHands containers for MCP auth proxy

The kafka container (eclipse-temurin:17-jdk) has no Python, causing
the auth proxy to fail with "Permission denied" when nohup tried to
exec the .py file directly. Now auto-installs python3 via apt/apk/yum
before starting the proxy.

Also adds rerun4 config for 3 remaining tasks (1 no-python fix,
2 Daytona build hang retries).

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

Author: sjarmak

agents/harnesses/openhands/agent.py

@@ -105,6 +105,15 @@ async def _configure_mcp(self, environment: BaseEnvironment) -> None:
             source_path=proxy_src,
             target_path="/tmp/sg_auth_proxy.py",
         )
+        # Ensure python3 is available (Java/Go images may not have it)
+        ensure_python = (
+            "command -v python3 >/dev/null 2>&1 || command -v python >/dev/null 2>&1 || { "
+            "(apt-get update && apt-get install -y --no-install-recommends python3) 2>/dev/null || "
+            "(apk add --no-cache python3) 2>/dev/null || "
+            "(yum install -y python3) 2>/dev/null || true; }"
+        )
+        await environment.exec(ensure_python)
+
         # Start proxy as background daemon (try python3, fall back to python)
         start_cmd = (
             f"SG_MCP_URL={mcp_endpoint} "

configs/openhands_mcp_rerun4.json

@@ -0,0 +1,39 @@
+{
+  "metadata": {
+    "name": "openhands_mcp_rerun4",
+    "description": "3-task rerun: 1 no-python-in-container fix, 2 Daytona build hangs (retry)",
+    "parent": "openhands_mcp_rerun3.json",
+    "reason": {
+      "no_python_in_container": [
+        "kafka-batch-accumulator-refac-001"
+      ],
+      "daytona_build_hang_retry": [
+        "pytorch-relu-gelu-fusion-fix-001",
+        "terraform-plan-null-unknown-fix-001"
+      ]
+    }
+  },
+  "tasks": [
+    {
+      "task_id": "kafka-batch-accumulator-refac-001",
+      "benchmark": "csb_sdlc_refactor",
+      "task_dir": "csb_sdlc_refactor/kafka-batch-accumulator-refac-001",
+      "language": "java",
+      "execution_env": "daytona"
+    },
+    {
+      "task_id": "pytorch-relu-gelu-fusion-fix-001",
+      "benchmark": "csb_sdlc_fix",
+      "task_dir": "csb_sdlc_fix/pytorch-relu-gelu-fusion-fix-001",
+      "language": "cpp",
+      "execution_env": "daytona"
+    },
+    {
+      "task_id": "terraform-plan-null-unknown-fix-001",
+      "benchmark": "csb_sdlc_fix",
+      "task_dir": "csb_sdlc_fix/terraform-plan-null-unknown-fix-001",
+      "language": "go",
+      "execution_env": "daytona"
+    }
+  ]
+}