rotation: maintain active user when deleting a user on the rotation

smoketest/rotationdeluser_test.go

@@ -0,0 +1,63 @@
+package smoketest
+
+import (
+	"encoding/json"
+	"fmt"
+	"testing"
+
+	"github.com/target/goalert/smoketest/harness"
+)
+
+// RotationDelUser tests that rotations preserve the active user when a user is deleted.
+func TestRotationDelUser(t *testing.T) {
+	t.Parallel()
+
+	const sql = `
+	insert into users (id, name, email)
+	values
+		({{uuid "uid1"}}, 'bob', 'joe'),
+		({{uuid "uid2"}}, 'ben', 'frank'),
+		({{uuid "uid3"}}, 'joe', 'bob');
+
+	insert into rotations (id, name, type, start_time, shift_length, time_zone)
+	values
+		({{uuid "rot1"}}, 'default rotation', 'daily', now(), 1, 'UTC');
+
+	insert into rotation_participants (rotation_id, user_id, position)
+	values
+		({{uuid "rot1"}}, {{uuid "uid1"}}, 0),
+		({{uuid "rot1"}}, {{uuid "uid2"}}, 1),
+		({{uuid "rot1"}}, {{uuid "uid3"}}, 2);
+	`
+	h := harness.NewHarness(t, sql, "add-daily-alert-metrics")
+	defer h.Close()
+
+	h.GraphQLQuery2(fmt.Sprintf(
+		`mutation{updateRotation(input:{id:"%s", activeUserIndex: 1})}`,
+		h.UUID("rot1"),
+	))
+
+	h.GraphQLQuery2(fmt.Sprintf(
+		`mutation{deleteAll(input:[{id:"%s", type: user}])}`,
+		h.UUID("uid1"),
+	))
+
+	resp := h.GraphQLQuery2(fmt.Sprintf(
+		`query{rotation(id:"%s"){activeUserIndex}}`,
+		h.UUID("rot1"),
+	))
+	var data struct {
+		Rotation struct {
+			ActiveUserIndex int
+		}
+	}
+	err := json.Unmarshal(resp.Data, &data)
+	if err != nil {
+		t.Fatal(err)
+		return
+	}
+	// 2nd user is now first, so index should be zero
+	if data.Rotation.ActiveUserIndex != 0 {
+		t.Errorf("expected activeUserIndex to be 0, got %d", data.Rotation.ActiveUserIndex)
+	}
+}

user/store.go

@@ -36,6 +36,8 @@ type Store struct {
 	rotationParts      *sql.Stmt
 	updateRotationPart *sql.Stmt
 	deleteRotationPart *sql.Stmt
+	rotActiveIndex     *sql.Stmt
+	rotSetActive       *sql.Stmt
 
 	findOneForUpdate *sql.Stmt
 
@@ -85,6 +87,9 @@ func NewStore(ctx context.Context, db *sql.DB) (*Store, error) {
 			WHERE id = $1
 		`),
 
+		rotActiveIndex: p.P(`SELECT position FROM rotation_state WHERE rotation_id = $1 FOR UPDATE`),
+		rotSetActive:   p.P(`UPDATE rotation_state SET position = $2, rotation_participant_id = $3 WHERE rotation_id = $1`),
+
 		setUserRole: p.P(`UPDATE users SET role = $2 WHERE id = $1`),
 		findAuthSubjects: p.P(`
 			select subject_id, user_id, provider_id
@@ -343,6 +348,7 @@ func withTx(ctx context.Context, tx *sql.Tx, stmt *sql.Stmt) *sql.Stmt {
 
 	return tx.StmtContext(ctx, stmt)
 }
+
 func (s *Store) requireTx(ctx context.Context, tx *sql.Tx, fn func(*sql.Tx) error) error {
 	return nil
 }
@@ -456,12 +462,22 @@ func (s *Store) removeUserFromRotation(ctx context.Context, tx *sql.Tx, userID,
 		participants = append(participants, p)
 	}
 
+	var activeIndex int
+	err = tx.StmtContext(ctx, s.rotActiveIndex).QueryRowContext(ctx, rotationID).Scan(&activeIndex)
+	if err != nil {
+		return fmt.Errorf("query active index: %w", err)
+	}
+
 	// update participant user IDs
 	var skipped bool
 	curIndex := -1
 	updatePart := tx.StmtContext(ctx, s.updateRotationPart)
-	for _, p := range participants {
+	for i, p := range participants {
 		if p.UserID == userID {
+			if i < activeIndex {
+				activeIndex--
+			}
+
 			skipped = true
 			continue
 		}
@@ -483,6 +499,11 @@ func (s *Store) removeUserFromRotation(ctx context.Context, tx *sql.Tx, userID,
 		}
 	}
 
+	_, err = tx.StmtContext(ctx, s.rotSetActive).ExecContext(ctx, rotationID, activeIndex, participants[activeIndex].ID)
+	if err != nil {
+		return fmt.Errorf("set active index: %w", err)
+	}
+
 	return nil
 }