From bc2071ef4288574ce00a7a979747fcd2ee57b67e Mon Sep 17 00:00:00 2001
From: lingniu <lingniu@lingnius-Mac-mini.local>
Date: Wed, 8 Jul 2026 14:41:53 +0800
Subject: [PATCH] fix(stats): enforce latest source endpoint only for projected
 daily mileage

---
 .superpowers/sdd/task-3-report.md                  | 14 ++++++++++++++
 .../internal/stats/source_mileage.go               |  2 +-
 .../internal/stats/source_mileage_test.go          |  8 +++++++-
 3 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/.superpowers/sdd/task-3-report.md b/.superpowers/sdd/task-3-report.md
index eb74f4bb..993e5f01 100644
--- a/.superpowers/sdd/task-3-report.md
+++ b/.superpowers/sdd/task-3-report.md
@@ -66,3 +66,17 @@ cd go/vehicle-gateway && go test ./internal/stats -run TestProjectDailyMileageSe
 cd go/vehicle-gateway && go test ./internal/stats -count=1
 # PASS: lingniu-vehicle-ingest/go/vehicle-gateway/internal/stats
 ```
+
+## Fix (reviewer findings #2)
+
+Corrected the remaining `projectDailyMileageSQL` contract issue so `trusted_source_endpoint` uses only `vehicle_data_source.latest_source_endpoint`:
+
+- In `go/vehicle-gateway/internal/stats/source_mileage.go`, changed the projection from:
+  `COALESCE(NULLIF(ds.latest_source_endpoint, ''), s.source_endpoint)`
+  to:
+  `ds.latest_source_endpoint`.
+- In `go/vehicle-gateway/internal/stats/source_mileage_test.go`, extended `TestProjectDailyMileageSelectsCandidateAndMarksSource` assertions to:
+  - require `ds.latest_source_endpoint` is selected, and
+  - explicitly verify no fallback expression using `s.source_endpoint` remains.
+
+This enforces the strict source-of-truth rule that endpoint data for final projection must come from latest connection metadata only, even when it is null/empty.
diff --git a/go/vehicle-gateway/internal/stats/source_mileage.go b/go/vehicle-gateway/internal/stats/source_mileage.go
index ccf572a4..9f8d65ba 100644
--- a/go/vehicle-gateway/internal/stats/source_mileage.go
+++ b/go/vehicle-gateway/internal/stats/source_mileage.go
@@ -192,7 +192,7 @@ SELECT
   s.latest_total_mileage_km,
   s.source_key,
   s.phone,
-  COALESCE(NULLIF(ds.latest_source_endpoint, ''), s.source_endpoint),
+  ds.latest_source_endpoint,
   s.sample_count
 FROM vehicle_daily_mileage_source s
 LEFT JOIN vehicle_data_source ds
diff --git a/go/vehicle-gateway/internal/stats/source_mileage_test.go b/go/vehicle-gateway/internal/stats/source_mileage_test.go
index 780cf50b..f64b7ec4 100644
--- a/go/vehicle-gateway/internal/stats/source_mileage_test.go
+++ b/go/vehicle-gateway/internal/stats/source_mileage_test.go
@@ -104,12 +104,18 @@ func TestProjectDailyMileageSelectsCandidateAndMarksSource(t *testing.T) {
 		"ORDER BY COALESCE(ds.trust_priority, 100)",
 		"s.quality_status = '" + QualityOK + "'",
 		"s.daily_mileage_km BETWEEN 0 AND",
-		"COALESCE(NULLIF(ds.latest_source_endpoint, ''), s.source_endpoint)",
+		"ds.latest_source_endpoint",
 	} {
 		if !strings.Contains(projectFinal, want) {
 			t.Fatalf("project query missing %q: %s", want, projectFinal)
 		}
 	}
+	if strings.Contains(projectFinal, "COALESCE(NULLIF(ds.latest_source_endpoint, ''), s.source_endpoint)") {
+		t.Fatalf("project query should not fallback to source endpoint: %s", projectFinal)
+	}
+	if strings.Contains(projectFinal, ", s.source_endpoint") {
+		t.Fatalf("project query should only project latest_source_endpoint: %s", projectFinal)
+	}
 	if !strings.Contains(markSelected, "UPDATE vehicle_daily_mileage_source s") || !strings.Contains(markSelected, "SET s.is_selected = 1") {
 		t.Fatalf("mark query should flag the elected source: %s", markSelected)
 	}