fix: add error logging to remaining nolint:errcheck scan sites for observability

backend/handlers/admin/custom_services.go

@@ -7,6 +7,7 @@ import (
 	"database/sql"
 	"encoding/json"
 	"errors"
+	"log"
 	"log/slog"
 	"net/http"
 	"strconv"
@@ -167,13 +168,15 @@ func GetCustomServices(w http.ResponseWriter, r *http.Request) {
 	// so pgx does not return "conn busy" on the same transaction.
 	if q != "" {
 		var countTotal int64
-//nolint:errcheck // zero value is acceptable fallback on scan failure
+		if err := db.Conn.QueryRow(r.Context(), "SELECT COUNT(*) FROM custom_services WHERE name ILIKE $1 OR description ILIKE $1", "%"+q+"%").Scan(&countTotal); err != nil {
-		_ = db.Conn.QueryRow(r.Context(), "SELECT COUNT(*) FROM custom_services WHERE name ILIKE $1 OR description ILIKE $1", "%"+q+"%").Scan(&countTotal)
+			log.Printf("Failed to scan filtered custom services count: %v", err)
+		}
 		total = countTotal
 	} else {
 		var countTotal int64
-//nolint:errcheck // zero value is acceptable fallback on scan failure
+		if err := db.Conn.QueryRow(r.Context(), "SELECT COUNT(*) FROM custom_services").Scan(&countTotal); err != nil {
-		_ = db.Conn.QueryRow(r.Context(), "SELECT COUNT(*) FROM custom_services").Scan(&countTotal)
+			log.Printf("Failed to scan custom services count: %v", err)
+		}
 		total = countTotal
 	}
 

backend/handlers/bookings/bookings.go

@@ -2776,8 +2776,9 @@ func ProgressBookingHandler(w http.ResponseWriter, r *http.Request) {
 
 			if bookingTotal > 0 {
 				var userBookingCount int
-//nolint:errcheck // zero value is acceptable fallback on scan failure
+				if err := tx.QueryRow(r.Context(), `SELECT COUNT(*) FROM bookings WHERE user_id = $1 AND status = 'completed'`, booking.User.ID).Scan(&userBookingCount); err != nil {
-				_ = tx.QueryRow(r.Context(), `SELECT COUNT(*) FROM bookings WHERE user_id = $1 AND status = 'completed'`, booking.User.ID).Scan(&userBookingCount)
+					log.Printf("Failed to scan user completed booking count: %v", err)
+				}
 
 				var milestoneCampaignID string
 				var milestonePercent float64
@@ -2817,8 +2818,9 @@ func ProgressBookingHandler(w http.ResponseWriter, r *http.Request) {
 				}
 				if !globalMilestoneApplied {
 					var globalCount int
-//nolint:errcheck // zero value is acceptable fallback on scan failure
+					if err := tx.QueryRow(r.Context(), `SELECT COUNT(*) FROM bookings WHERE status = 'completed'`).Scan(&globalCount); err != nil {
-					_ = tx.QueryRow(r.Context(), `SELECT COUNT(*) FROM bookings WHERE status = 'completed'`).Scan(&globalCount)
+						log.Printf("Failed to scan global completed booking count: %v", err)
+					}
 
 				var hasInPersonPayment bool
 				if err := tx.QueryRow(r.Context(), `
@@ -2863,8 +2865,9 @@ func ProgressBookingHandler(w http.ResponseWriter, r *http.Request) {
 				}
 
 				var firstVisitDate time.Time
-//nolint:errcheck // zero value is acceptable fallback on scan failure
+				if err := tx.QueryRow(r.Context(), `SELECT MIN(start_time) FROM bookings WHERE user_id = $1 AND status = 'completed'`, booking.User.ID).Scan(&firstVisitDate); err != nil {
-				_ = tx.QueryRow(r.Context(), `SELECT MIN(start_time) FROM bookings WHERE user_id = $1 AND status = 'completed'`, booking.User.ID).Scan(&firstVisitDate)
+					log.Printf("Failed to scan first visit date: %v", err)
+				}
 				if !firstVisitDate.IsZero() {
 					annRows, err := tx.Query(r.Context(), `
 					SELECT id, discount_percent, milestone_value, milestone_unit FROM discount_campaigns

backend/handlers/bookings/manage.go

@@ -1685,8 +1685,9 @@ func AdminListEditRequestsHandler(w http.ResponseWriter, r *http.Request) {
 	var total int
 
 	// Count query (no ORDER BY needed).
-//nolint:errcheck // zero value is acceptable fallback on scan failure
+	if err := db.Conn.QueryRow(r.Context(), "SELECT COUNT(*) FROM booking_edit_requests").Scan(&total); err != nil {
-	_ = db.Conn.QueryRow(r.Context(), "SELECT COUNT(*) FROM booking_edit_requests").Scan(&total)
+		log.Printf("Failed to scan booking edit request count: %v", err)
+	}
 
 	rows, err := db.Conn.Query(r.Context(), baseQuery, args...)
 	if err != nil {

backend/handlers/notifications/notifications.go

@@ -126,8 +126,9 @@ func GetNotifications(w http.ResponseWriter, r *http.Request) {
 	if !includeAcknowledged {
 		countWhere += " WHERE an.acknowledged_at IS NULL"
 	}
-//nolint:errcheck // zero value is acceptable fallback on scan failure
+	if err := db.Conn.QueryRow(r.Context(), "SELECT COUNT(*) FROM admin_notifications an"+countWhere).Scan(&total); err != nil {
-	_ = db.Conn.QueryRow(r.Context(), "SELECT COUNT(*) FROM admin_notifications an"+countWhere).Scan(&total)
+		log.Printf("Failed to scan notification count: %v", err)
+	}
 
 	// Query
 	rows, err := db.Conn.Query(r.Context(), baseQuery, args...)

backend/handlers/payments/giftcards.go

@@ -207,11 +207,13 @@ func GetGiftCards(w http.ResponseWriter, r *http.Request) {
 		if searchTerm != "" {
 			countArgs = append(countArgs, "%"+searchTerm+"%")
 		}
-//nolint:errcheck // zero value is acceptable fallback on scan failure
+		if err := db.Conn.QueryRow(ctx, "SELECT COUNT(*) FROM gift_cards "+whereSQL, countArgs...).Scan(&gcTotal); err != nil {
-		_ = db.Conn.QueryRow(ctx, "SELECT COUNT(*) FROM gift_cards "+whereSQL, countArgs...).Scan(&gcTotal)
+			log.Printf("Failed to scan filtered gift card count: %v", err)
+		}
 	} else {
-//nolint:errcheck // zero value is acceptable fallback on scan failure
+		if err := db.Conn.QueryRow(ctx, "SELECT COUNT(*) FROM gift_cards").Scan(&gcTotal); err != nil {
-		_ = db.Conn.QueryRow(ctx, "SELECT COUNT(*) FROM gift_cards").Scan(&gcTotal)
+			log.Printf("Failed to scan gift card count: %v", err)
+		}
 	}
 
 	gcRows, err := db.Conn.Query(ctx, gcListQuery, gcListArgs...)
@@ -283,13 +285,15 @@ func GetGiftCards(w http.ResponseWriter, r *http.Request) {
 
 	// Count query for user balances.
 	if searchTerm != "" {
-//nolint:errcheck // zero value is acceptable fallback on scan failure
+		if err := db.Conn.QueryRow(ctx, `SELECT COUNT(*) FROM user_giftcard_balances b
-		_ = db.Conn.QueryRow(ctx, `SELECT COUNT(*) FROM user_giftcard_balances b
 			JOIN users u ON b.user_id = u.id
-			WHERE u.n_first_name ILIKE $1 OR u.n_last_name ILIKE $1 OR u.email ILIKE $1`, "%"+searchTerm+"%").Scan(&ubTotal)
+			WHERE u.n_first_name ILIKE $1 OR u.n_last_name ILIKE $1 OR u.email ILIKE $1`, "%"+searchTerm+"%").Scan(&ubTotal); err != nil {
+			log.Printf("Failed to scan filtered user balance count: %v", err)
+		}
 	} else {
-//nolint:errcheck // zero value is acceptable fallback on scan failure
+		if err := db.Conn.QueryRow(ctx, "SELECT COUNT(*) FROM user_giftcard_balances").Scan(&ubTotal); err != nil {
-		_ = db.Conn.QueryRow(ctx, "SELECT COUNT(*) FROM user_giftcard_balances").Scan(&ubTotal)
+			log.Printf("Failed to scan user balance count: %v", err)
+		}
 	}
 
 	for ubRows.Next() {

backend/handlers/payments/handlers.go

@@ -165,8 +165,9 @@ func calculateDiscountPreview(ctx context.Context, bookingID string, userID stri
 		ORDER BY discount_percent DESC LIMIT 1
 	`).Scan(&campaignID, &campaignPercent, &campaignName); err == nil && campaignID != "" {
 		var exists int
-		//nolint:errcheck // zero value is acceptable fallback on scan failure
+		if err := db.Conn.QueryRow(ctx, `SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND source_id = $2`, bookingID, campaignID).Scan(&exists); err != nil {
-		_ = db.Conn.QueryRow(ctx, `SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND source_id = $2`, bookingID, campaignID).Scan(&exists)
+			log.Printf("Failed to scan campaign discount existence: %v", err)
+		}
 		if exists == 0 {
 			amount := roundTo2(bookingTotal * campaignPercent / 100)
 			resp.Discounts = append(resp.Discounts, DiscountPreview{
@@ -180,8 +181,9 @@ func calculateDiscountPreview(ctx context.Context, bookingID string, userID stri
 	}
 
 	var userBookingCount int
-	//nolint:errcheck // zero value is acceptable fallback on scan failure
+	if err := db.Conn.QueryRow(ctx, `SELECT COUNT(*) FROM bookings WHERE user_id = $1 AND status = 'completed'`, userID).Scan(&userBookingCount); err != nil {
-	_ = db.Conn.QueryRow(ctx, `SELECT COUNT(*) FROM bookings WHERE user_id = $1 AND status = 'completed'`, userID).Scan(&userBookingCount)
+		log.Printf("Failed to scan user completed booking count: %v", err)
+	}
 
 	var milestoneCampaignID string
 	var milestonePercent float64
@@ -197,8 +199,9 @@ func calculateDiscountPreview(ctx context.Context, bookingID string, userID stri
 
 	if milestoneCampaignID != "" {
 		var exists int
-		//nolint:errcheck // zero value is acceptable fallback on scan failure
+		if err := db.Conn.QueryRow(ctx, `SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND source_id = $2`, bookingID, milestoneCampaignID).Scan(&exists); err != nil {
-		_ = db.Conn.QueryRow(ctx, `SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND source_id = $2`, bookingID, milestoneCampaignID).Scan(&exists)
+			log.Printf("Failed to scan milestone discount existence: %v", err)
+		}
 		if exists == 0 {
 			amount := roundTo2(bookingTotal * milestonePercent / 100)
 			resp.Discounts = append(resp.Discounts, DiscountPreview{
@@ -212,8 +215,9 @@ func calculateDiscountPreview(ctx context.Context, bookingID string, userID stri
 	}
 
 	var firstVisitDate time.Time
-	//nolint:errcheck // zero value is acceptable fallback on scan failure
+	if err := db.Conn.QueryRow(ctx, `SELECT MIN(start_time) FROM bookings WHERE user_id = $1 AND status = 'completed'`, userID).Scan(&firstVisitDate); err != nil {
-	_ = db.Conn.QueryRow(ctx, `SELECT MIN(start_time) FROM bookings WHERE user_id = $1 AND status = 'completed'`, userID).Scan(&firstVisitDate)
+		log.Printf("Failed to scan first visit date: %v", err)
+	}
 	if !firstVisitDate.IsZero() {
 		type annCamp struct {
 			id    string
@@ -238,9 +242,10 @@ func calculateDiscountPreview(ctx context.Context, bookingID string, userID stri
 			annRows.Close()
 
 			for _, c := range campaigns {
-				var exists int
+		var exists int
-				//nolint:errcheck // zero value is acceptable fallback on scan failure
+		if err := db.Conn.QueryRow(ctx, `SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND source_id = $2`, bookingID, c.id).Scan(&exists); err != nil {
-				_ = db.Conn.QueryRow(ctx, `SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND source_id = $2`, bookingID, c.id).Scan(&exists)
+			log.Printf("Failed to scan anniversary discount existence: %v", err)
+		}
 				if exists > 0 {
 					continue
 				}
@@ -276,8 +281,9 @@ func calculateDiscountPreview(ctx context.Context, bookingID string, userID stri
 		LIMIT 1
 	`, userID).Scan(&rdID, &rdPercent); err == nil && rdID != "" {
 		exists := 0
-		//nolint:errcheck // zero value is acceptable fallback on scan failure
+		if err := db.Conn.QueryRow(ctx, `SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND discount_source = 'referral' AND source_id = $2`, bookingID, rdID).Scan(&exists); err != nil {
-		_ = db.Conn.QueryRow(ctx, `SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND discount_source = 'referral' AND source_id = $2`, bookingID, rdID).Scan(&exists)
+			log.Printf("Failed to scan referral discount existence: %v", err)
+		}
 		if exists == 0 {
 			amount := roundTo2(bookingTotal * rdPercent / 100)
 			resp.Discounts = append(resp.Discounts, DiscountPreview{
@@ -1080,11 +1086,12 @@ func CreateBookingPayment(w http.ResponseWriter, r *http.Request) {
 // would create a credit balance or require a refund.
 func applyEligibleCampaignsAtPayment(ctx context.Context, q db.Querier, bookingID string, userID string) {
 	var existingPayment int
-	//nolint:errcheck // zero value is acceptable fallback on scan failure
+	if err := q.QueryRow(ctx, `
-	_ = q.QueryRow(ctx, `
 		SELECT COUNT(*) FROM payments
 		WHERE booking_id = $1 AND status = 'completed' AND payment_method NOT IN ('discount', 'on_the_house')
-	`, bookingID).Scan(&existingPayment)
+	`, bookingID).Scan(&existingPayment); err != nil {
+		log.Printf("Failed to scan existing payment count: %v", err)
+	}
 	// Only block if this is the 2nd+ real payment — the first payment should still
 	// trigger discount application (existingPayment counts already-completed payments
 	// visible within the transaction, including the just-inserted one).
@@ -1113,8 +1120,9 @@ func applyEligibleCampaignsAtPayment(ctx context.Context, q db.Querier, bookingI
 		ORDER BY discount_percent DESC LIMIT 1
 	`).Scan(&campaignID, &campaignPercent); err == nil && campaignID != "" {
 		var exists int
-		//nolint:errcheck // zero value is acceptable fallback on scan failure
+		if err := q.QueryRow(ctx, `SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND source_id = $2`, bookingID, campaignID).Scan(&exists); err != nil {
-		_ = q.QueryRow(ctx, `SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND source_id = $2`, bookingID, campaignID).Scan(&exists)
+			log.Printf("Failed to scan time-based campaign discount existence: %v", err)
+		}
 		if exists == 0 {
 			discountAmount := roundTo2(bookingTotal * campaignPercent / 100)
 			if _, err := q.Exec(ctx, `
@@ -1139,8 +1147,9 @@ func applyEligibleCampaignsAtPayment(ctx context.Context, q db.Querier, bookingI
 	}
 
 	var userBookingCount int
-	//nolint:errcheck // zero value is acceptable fallback on scan failure
+	if err := q.QueryRow(ctx, `SELECT COUNT(*) FROM bookings WHERE user_id = $1 AND status = 'completed'`, userID).Scan(&userBookingCount); err != nil {
-	_ = q.QueryRow(ctx, `SELECT COUNT(*) FROM bookings WHERE user_id = $1 AND status = 'completed'`, userID).Scan(&userBookingCount)
+		log.Printf("Failed to scan user booking count: %v", err)
+	}
 
 	var milestoneCampaignID string
 	var milestonePercent float64
@@ -1155,8 +1164,9 @@ func applyEligibleCampaignsAtPayment(ctx context.Context, q db.Querier, bookingI
 
 	if milestoneCampaignID != "" {
 		var exists int
-		//nolint:errcheck // zero value is acceptable fallback on scan failure
+		if err := q.QueryRow(ctx, `SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND source_id = $2`, bookingID, milestoneCampaignID).Scan(&exists); err != nil {
-		_ = q.QueryRow(ctx, `SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND source_id = $2`, bookingID, milestoneCampaignID).Scan(&exists)
+			log.Printf("Failed to scan milestone campaign discount existence: %v", err)
+		}
 		if exists == 0 {
 			discountAmount := roundTo2(bookingTotal * milestonePercent / 100)
 			if _, err := q.Exec(ctx, `
@@ -1181,8 +1191,9 @@ func applyEligibleCampaignsAtPayment(ctx context.Context, q db.Querier, bookingI
 	}
 
 	var firstVisitDate time.Time
-	//nolint:errcheck // zero value is acceptable fallback on scan failure
+	if err := q.QueryRow(ctx, `SELECT MIN(start_time) FROM bookings WHERE user_id = $1 AND status = 'completed'`, userID).Scan(&firstVisitDate); err != nil {
-	_ = q.QueryRow(ctx, `SELECT MIN(start_time) FROM bookings WHERE user_id = $1 AND status = 'completed'`, userID).Scan(&firstVisitDate)
+		log.Printf("Failed to scan first visit date: %v", err)
+	}
 	if !firstVisitDate.IsZero() {
 		annRows, err := q.Query(ctx, `
 			SELECT id, discount_percent, milestone_value, milestone_unit FROM discount_campaigns
@@ -1206,9 +1217,10 @@ func applyEligibleCampaignsAtPayment(ctx context.Context, q db.Querier, bookingI
 			annRows.Close()
 
 			for _, c := range campaigns {
-				var exists int
+		var exists int
-				//nolint:errcheck // zero value is acceptable fallback on scan failure
+			if err := q.QueryRow(ctx, `SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND source_id = $2`, bookingID, c.id).Scan(&exists); err != nil {
-				_ = q.QueryRow(ctx, `SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND source_id = $2`, bookingID, c.id).Scan(&exists)
+				log.Printf("Failed to scan anniversary discount existence: %v", err)
+			}
 				if exists > 0 {
 					continue
 				}
@@ -1256,8 +1268,9 @@ func applyEligibleCampaignsAtPayment(ctx context.Context, q db.Querier, bookingI
 		SELECT payment_method FROM payments WHERE booking_id = $1 AND payment_method NOT IN ('discount', 'on_the_house') ORDER BY created_at ASC LIMIT 1
 	`, bookingID).Scan(&firstPaymentMethod); err == nil && firstPaymentMethod == "in_person_card" {
 		var globalCount int
-		//nolint:errcheck // zero value is acceptable fallback on scan failure
+		if err := q.QueryRow(ctx, `SELECT COUNT(*) FROM bookings WHERE status = 'completed'`).Scan(&globalCount); err != nil {
-		_ = q.QueryRow(ctx, `SELECT COUNT(*) FROM bookings WHERE status = 'completed'`).Scan(&globalCount)
+			log.Printf("Failed to scan global completed booking count: %v", err)
+		}
 
 		var globalCampaignID string
 		var globalPercent float64
@@ -1274,8 +1287,9 @@ func applyEligibleCampaignsAtPayment(ctx context.Context, q db.Querier, bookingI
 
 		if globalCampaignID != "" {
 			var exists int
-			//nolint:errcheck // zero value is acceptable fallback on scan failure
+			if err := q.QueryRow(ctx, `SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND source_id = $2`, bookingID, globalCampaignID).Scan(&exists); err != nil {
-			_ = q.QueryRow(ctx, `SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND source_id = $2`, bookingID, globalCampaignID).Scan(&exists)
+				log.Printf("Failed to scan global campaign discount existence: %v", err)
+			}
 			if exists == 0 {
 				discountAmount := roundTo2(bookingTotal * globalPercent / 100)
 				if _, err := q.Exec(ctx, `
@@ -1310,8 +1324,9 @@ func applyEligibleCampaignsAtPayment(ctx context.Context, q db.Querier, bookingI
 			LIMIT 1
 		`, userID).Scan(&rdID, &rdPercent); err == nil && rdID != "" {
 			exists := 0
-			//nolint:errcheck // zero value is acceptable fallback on scan failure
+			if err := q.QueryRow(ctx, `SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND discount_source = 'referral' AND source_id = $2`, bookingID, rdID).Scan(&exists); err != nil {
-			_ = q.QueryRow(ctx, `SELECT 1 FROM booking_discounts WHERE booking_id = $1 AND discount_source = 'referral' AND source_id = $2`, bookingID, rdID).Scan(&exists)
+				log.Printf("Failed to scan referral discount existence: %v", err)
+			}
 			if exists == 0 {
 				discountAmount := roundTo2(bookingTotal * rdPercent / 100)
 				if _, err := q.Exec(ctx, `

backend/handlers/user/profile.go

@@ -565,13 +565,15 @@ func ListAdminUsersHandler(w http.ResponseWriter, r *http.Request) {
 	// Run BEFORE the data query to avoid "conn busy" errors when routing
 	// through a per-test transaction (pgx.Tx does not support concurrent queries).
 	if searchTerm != "" {
-		//nolint:errcheck // zero value is acceptable fallback on scan failure
+		if err := db.Conn.QueryRow(r.Context(), `SELECT COUNT(DISTINCT u.id) FROM users u
-		_ = db.Conn.QueryRow(r.Context(), `SELECT COUNT(DISTINCT u.id) FROM users u
 			LEFT JOIN bookings b ON u.id = b.user_id
-			WHERE u.fn ILIKE $1 OR u.email ILIKE $1 OR u.phone ILIKE $1`, "%"+searchTerm+"%").Scan(&total)
+			WHERE u.fn ILIKE $1 OR u.email ILIKE $1 OR u.phone ILIKE $1`, "%"+searchTerm+"%").Scan(&total); err != nil {
+			log.Printf("Failed to scan filtered user count: %v", err)
+		}
 	} else {
-		//nolint:errcheck // zero value is acceptable fallback on scan failure
+		if err := db.Conn.QueryRow(r.Context(), "SELECT COUNT(*) FROM users").Scan(&total); err != nil {
-		_ = db.Conn.QueryRow(r.Context(), "SELECT COUNT(*) FROM users").Scan(&total)
+			log.Printf("Failed to scan user count: %v", err)
+		}
 	}
 
 	// Get users list