fix: harden artifact verifier against missing patch command

- Add `patch` to Dockerfile.artifact_only apt install list
- Wrap subprocess calls in try/except FileNotFoundError in
  artifact_verifier_lib.sh so missing executables don't crash the
  Python heredoc
- Make apply_patches_from_review_json non-fatal in test.sh (|| echo)
  so scoring continues even when patches fail to apply

Verified: run scored 0.55 with these fixes (was RewardFileNotFoundError).

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

Author: sjarmak

benchmarks/ccb_test/aspnetcore-code-review-001/environment/Dockerfile.artifact_only

@@ -9,6 +9,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     git \
     ca-certificates \
     curl \
+    patch \
     python3 \
     ripgrep \
     && rm -rf /var/lib/apt/lists/*

benchmarks/ccb_test/aspnetcore-code-review-001/tests/artifact_verifier_lib.sh

@@ -158,34 +158,43 @@ for entry in reported:
         pf_path = pf.name
 
     # Try git apply
-    result = subprocess.run(
-        ["git", "apply", "--allow-empty", pf_path],
-        cwd=verify_repo, capture_output=True, text=True
-    )
-    if result.returncode == 0:
-        applied += 1
-        os.unlink(pf_path)
-        continue
+    try:
+        result = subprocess.run(
+            ["git", "apply", "--allow-empty", pf_path],
+            cwd=verify_repo, capture_output=True, text=True
+        )
+        if result.returncode == 0:
+            applied += 1
+            os.unlink(pf_path)
+            continue
+    except FileNotFoundError:
+        pass
 
     # Fallback: patch -p1 --fuzz=3
-    result = subprocess.run(
-        ["patch", "-p1", "--fuzz=3", "-i", pf_path],
-        cwd=verify_repo, capture_output=True, text=True
-    )
-    if result.returncode == 0:
-        applied += 1
-        os.unlink(pf_path)
-        continue
+    try:
+        result = subprocess.run(
+            ["patch", "-p1", "--fuzz=3", "-i", pf_path],
+            cwd=verify_repo, capture_output=True, text=True
+        )
+        if result.returncode == 0:
+            applied += 1
+            os.unlink(pf_path)
+            continue
+    except FileNotFoundError:
+        print("[artifact_verifier] 'patch' not installed, skipping fallback", file=sys.stderr)
 
     # Fallback: git apply with 3way
-    result = subprocess.run(
-        ["git", "apply", "--allow-empty", "--3way", pf_path],
-        cwd=verify_repo, capture_output=True, text=True
-    )
-    if result.returncode == 0:
-        applied += 1
-        os.unlink(pf_path)
-        continue
+    try:
+        result = subprocess.run(
+            ["git", "apply", "--allow-empty", "--3way", pf_path],
+            cwd=verify_repo, capture_output=True, text=True
+        )
+        if result.returncode == 0:
+            applied += 1
+            os.unlink(pf_path)
+            continue
+    except FileNotFoundError:
+        pass
 
     failed += 1
     file_name = entry.get("file", "unknown")

benchmarks/ccb_test/aspnetcore-code-review-001/tests/test.sh

@@ -32,7 +32,7 @@ if [ "${ARTIFACT_ONLY:-false}" = "true" ]; then
         exit 0
     fi
     echo "Artifact mode: review.json found, applying patches to ${VERIFY_REPO}"
-    apply_patches_from_review_json /workspace/review.json
+    apply_patches_from_review_json /workspace/review.json || echo "[verifier] Patch application returned non-zero (non-fatal, scoring continues)"
 else
     # Legacy mode: check git changes in workspace
     UNSTAGED_COUNT=$(git diff --stat 2>/dev/null | wc -l)