fix: history command shows n/a for non-scorable repos instead of 100.0/A

src/arbiter/__main__.py

@@ -1071,19 +1071,6 @@ def cmd_diff(args: argparse.Namespace) -> None:
         sys.exit(1)
 
 
-def _score_to_grade(score: float) -> str:
-    """Convert a numeric score to a letter grade."""
-    if score >= 90:
-        return "A"
-    if score >= 80:
-        return "B"
-    if score >= 70:
-        return "C"
-    if score >= 60:
-        return "D"
-    return "F"
-
-
 def _compute_deltas(rows: list[dict]) -> list[dict]:
     """Add a 'delta' key to each row based on previous score for the same repo.
 
@@ -1131,20 +1118,24 @@ def cmd_history(args: argparse.Namespace) -> None:
         print("|------|------|-------|-------|-------|")
         for r in rows_with_delta:
             ts = r["timestamp"][:10]
+            loc = r.get("total_loc", 0) or 0
             score = r["overall_score"] or 0
-            grade = _score_to_grade(score)
-            print(f"| {ts} | {r['repo_name']} | {score:.1f} | {grade} | {r['delta']} |")
+            grade = _grade_score(score, loc)
+            score_str = "n/a" if loc <= 0 else f"{score:.1f}"
+            print(f"| {ts} | {r['repo_name']} | {score_str} | {grade} | {r['delta']} |")
         return
 
     # Default: plain text table
     print(f"{'Date':12s} {'Repo':30s} {'Score':>6s} {'Grade':>6s} {'Delta':>8s}")
     print("-" * 66)
     for r in rows_with_delta:
         ts = r["timestamp"][:10]
+        loc = r.get("total_loc", 0) or 0
         score = r["overall_score"] or 0
-        grade = _score_to_grade(score)
+        grade = _grade_score(score, loc)
         name = (r.get("repo_name") or "?")[:30]
-        print(f"{ts:12s} {name:30s} {score:6.1f} {grade:>6s} {r['delta']:>8s}")
+        score_str = "n/a" if loc <= 0 else f"{score:6.1f}"
+        print(f"{ts:12s} {name:30s} {score_str:>6s} {grade:>6s} {r['delta']:>8s}")
     _print_footer()
 
 

tests/test_history.py

@@ -15,7 +15,7 @@
     cmd_trend_chart,
     _compute_deltas,
     _ascii_bar,
-    _score_to_grade,
+    _grade_score,
 )
 
 
@@ -256,14 +256,19 @@ def test_trend_chart_empty(tmp_path: Path, capsys) -> None:
 
 
 # ---------------------------------------------------------------------------
-# _score_to_grade
+# _grade_score
 # ---------------------------------------------------------------------------
 
 
-def test_score_to_grade() -> None:
-    assert _score_to_grade(95) == "A"
-    assert _score_to_grade(90) == "A"
-    assert _score_to_grade(85) == "B"
-    assert _score_to_grade(75) == "C"
-    assert _score_to_grade(65) == "D"
-    assert _score_to_grade(50) == "F"
+def test_grade_score() -> None:
+    assert _grade_score(95, total_loc=100) == "A"
+    assert _grade_score(90, total_loc=100) == "A"
+    assert _grade_score(85, total_loc=100) == "B"
+    assert _grade_score(75, total_loc=100) == "C"
+    assert _grade_score(65, total_loc=100) == "D"
+    assert _grade_score(50, total_loc=100) == "F"
+    assert _grade_score(100, total_loc=0) == "N/A"
+
+def test_grade_score_non_scorable() -> None:
+    assert _grade_score(100.0, total_loc=0) == "N/A"
+    assert _grade_score(0, total_loc=0) == "N/A"