feat(opencode_review): python fallback for summary fields

pilot/opencode_review.py

@@ -55,6 +55,8 @@ import time
 import urllib.error
 import urllib.request
 
+from ai_review import is_test_path
+
 # Where the factory lives (opencode.json + .opencode/). Default: the pragent
 # repo root (this file is at <root>/pilot/opencode_review.py).
 _DEFAULT_FACTORY = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
@@ -565,6 +567,14 @@ _LENS_ID_RE = re.compile(r"^[a-z0-9-]{1,32}$")
 SEVERITY_ORDER = ("low", "medium", "high", "critical")
 SEVERITY_RANK = {s: i for i, s in enumerate(SEVERITY_ORDER)}
 
+# Local emoji map for the synthesized walkthrough. Kept separate from
+# `ai_review._SEVERITY_EMOJI` (which also has "trivial"/"info"/"nit") so
+# this stays a small surface for the fallback path.
+_SEVERITY_EMOJI_SUMMARY = {
+    "critical": "🔴", "high": "🔴", "medium": "🟡",
+    "low": "🔵", "trivial": "⚪", "info": "⚪",
+}
+
 
 @_dc.dataclass(frozen=True)
 class ReviewerSpec:
@@ -917,12 +927,69 @@ def _synthesize_summary_fields(
     (`ai_review.parse_review_output` extracts them as the 5th, 6th, and
     7th tuple elements, defaulting to `[]` / `""` when missing).
 
-    STUB for Task 7. The real implementation arrives in Task 8; for now
-    every return is empty so the synthesized JSON shape stays parseable
-    and downstream tests that default the new fields to `[]` / `""`
-    continue to pass.
+    Real implementation (Task 8). Python fallback used when the lens
+    fan-out path is engaged (the synthesized JSON fence in `run_lenses_review`
+    has no model to call, so we build these fields deterministically from
+    the merged findings + the diff):
+      - walkthrough: one line per changed file. When findings exist, group
+        by path and pick the peak-severity problem as the headline; when
+        no findings exist, just announce "changed".
+      - risk_verdict: a one-line verdict driven by the highest severity
+        bucket that has any findings ("Critical risk" / "High risk" /
+        "Medium risk" / "Low risk").
+      - test_coverage: "Tests changed" if any changed path matches
+        `is_test_path`, else "No tests for behavioral change in `<path>`."
+        pointing at the first non-test path.
     """
-    return [], "", ""
+    # walkthrough
+    walkthrough: list[str] = []
+    if findings:
+        by_path: dict[str, list[dict]] = {}
+        for f in findings:
+            by_path.setdefault(f.get("path", "?"), []).append(f)
+        for path, group in sorted(by_path.items()):
+            peak = max(
+                group,
+                key=lambda x: SEVERITY_RANK.get(x.get("severity", "low"), 0),
+            )
+            problem_lines = (peak.get("problem") or "").splitlines()
+            problem = problem_lines[0][:80].strip() if problem_lines else ""
+            emoji = _SEVERITY_EMOJI_SUMMARY.get(
+                peak.get("severity", "low"), "⚪")
+            walkthrough.append(f"`{path}` — {emoji} {problem}")
+    else:
+        files = changed_paths if changed_paths is not None else changed_files(diff)
+        for p in files:
+            walkthrough.append(f"`{p}` — changed")
+
+    # risk_verdict
+    sev_counts = {"critical": 0, "high": 0, "medium": 0, "low": 0}
+    for f in findings:
+        s = f.get("severity", "low")
+        sev_counts[s] = sev_counts.get(s, 0) + 1
+    if sev_counts["critical"]:
+        rv = f"Critical risk: {sev_counts['critical']} critical finding(s)."
+    elif sev_counts["high"]:
+        rv = f"High risk: {sev_counts['high']} high finding(s)."
+    elif sev_counts["medium"]:
+        rv = f"Medium risk: {sev_counts['medium']} medium finding(s)."
+    else:
+        rv = "Low risk: clean or minor nits only."
+
+    # test_coverage
+    paths = changed_paths if changed_paths is not None else changed_files(diff)
+    test_changed = any(is_test_path(p) for p in paths)
+    non_test = [p for p in paths if not is_test_path(p)]
+    if test_changed and non_test:
+        tc = "Tests changed"
+    elif non_test:
+        tc = f"No tests for behavioral change in `{non_test[0]}`."
+    elif test_changed:
+        tc = "Tests changed"
+    else:
+        tc = ""
+
+    return walkthrough, rv, tc
 
 
 # ---------------------------------------------------------------------------
@@ -1334,6 +1401,8 @@ def run_lenses_review(
         )
         synthesized_payload = {
             "summary": summary,
+            "summary_changes": [],
+            "risks": [],
             "walkthrough": walkthrough,
             "risk_verdict": risk_verdict,
             "test_coverage": test_coverage,

tests/pilot/test_opencode_review.py

@@ -859,3 +859,49 @@ def test_no_surface_response_zero_lenses_wording():
     summary, findings, _c, _r, _w, _rv, _tc = ai_review.parse_review_output(text)
     assert findings == []
     assert "after path filtering" in summary
+
+
+# ---------------------------------------------------------------------------
+# _synthesize_summary_fields — Task 8: real Python fallback implementation
+# ---------------------------------------------------------------------------
+
+
+def test_synthesize_walkthrough_groups_findings_by_path():
+    findings = [
+        {"path": "a.py", "line": 1, "severity": "medium", "problem": "fix x"},
+        {"path": "b.py", "line": 2, "severity": "high", "problem": "fix y"},
+    ]
+    w, _, _ = oc._synthesize_summary_fields(findings, "")
+    assert any("a.py" in line for line in w)
+    assert any("b.py" in line for line in w)
+
+
+def test_synthesize_walkthrough_empty_when_no_findings_uses_changed_files():
+    w, _, _ = oc._synthesize_summary_fields(
+        [],
+        "diff --git a/x.py b/x.py\n@@ -1 +1 @@\n-old\n+new\n+++ b/x.py\n",
+    )
+    assert any("x.py" in line for line in w)
+
+
+def test_synthesize_risk_verdict_critical():
+    findings = [{"severity": "critical"}]
+    _, rv, _ = oc._synthesize_summary_fields(findings, "")
+    assert "Critical risk" in rv
+
+
+def test_synthesize_risk_verdict_clean():
+    _, rv, _ = oc._synthesize_summary_fields([], "")
+    assert "Low risk" in rv
+
+
+def test_synthesize_test_coverage_with_test_path():
+    _, _, tc = oc._synthesize_summary_fields(
+        [], "+diff\n", changed_paths=["pilot/foo.py", "tests/test_foo.py"])
+    assert tc == "Tests changed"
+
+
+def test_synthesize_test_coverage_missing_tests():
+    _, _, tc = oc._synthesize_summary_fields(
+        [], "+diff\n", changed_paths=["pilot/foo.py"])
+    assert "No tests for behavioral change" in tc