From af0162f0dfcee57d4b572df5bb4d4a0b15887adc Mon Sep 17 00:00:00 2001
From: Burak Sekili <buraksekili@gmail.com>
Date: Thu, 8 Jul 2021 14:51:37 +0300
Subject: [PATCH] Fix fetching user members of an empty group (#1436)

Signed-off-by: Burak Sekili <buraksekili@gmail.com>
---
 users/postgres/users.go      | 18 +++++++++++++-----
 users/postgres/users_test.go | 13 +++++++++++++
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/users/postgres/users.go b/users/postgres/users.go
index 3e4a168b..ebec64dc 100644
--- a/users/postgres/users.go
+++ b/users/postgres/users.go
@@ -168,13 +168,21 @@ func (ur userRepository) RetrieveAll(ctx context.Context, offset, limit uint64,
 	if mq != "" {
 		query = append(query, mq)
 	}
-	if len(userIDs) > 0 {
-		query = append(query, fmt.Sprintf("id IN ('%s')", strings.Join(userIDs, "','")))
-	}
-	if len(query) > 0 {
-		emq = fmt.Sprintf(" WHERE %s", strings.Join(query, " AND "))
+
+	if len(userIDs) == 0 {
+		return users.UserPage{
+			Users: []users.User{},
+			PageMetadata: users.PageMetadata{
+				Total:  0,
+				Offset: offset,
+				Limit:  limit,
+			},
+		}, nil
 	}
 
+	query = append(query, fmt.Sprintf("id IN ('%s')", strings.Join(userIDs, "','")))
+	emq = fmt.Sprintf(" WHERE %s", strings.Join(query, " AND "))
+
 	q := fmt.Sprintf(`SELECT id, email, metadata FROM users %s ORDER BY email LIMIT :limit OFFSET :offset;`, emq)
 	params := map[string]interface{}{
 		"limit":    limit,
diff --git a/users/postgres/users_test.go b/users/postgres/users_test.go
index 6c8d7e50..cf659be2 100644
--- a/users/postgres/users_test.go
+++ b/users/postgres/users_test.go
@@ -137,6 +137,7 @@ func TestRetrieveAll(t *testing.T) {
 			limit:  nUsers,
 			size:   nUsers,
 			total:  nUsers,
+			ids:    ids,
 		},
 		"retrieve all users by email with limit and offset": {
 			email:  "All",
@@ -144,6 +145,7 @@ func TestRetrieveAll(t *testing.T) {
 			limit:  5,
 			size:   5,
 			total:  nUsers,
+			ids:    ids,
 		},
 		"retrieve all users by metadata": {
 			email:    "All",
@@ -152,6 +154,7 @@ func TestRetrieveAll(t *testing.T) {
 			size:     metaNum,
 			total:    nUsers,
 			metadata: meta,
+			ids:      ids,
 		},
 		"retrieve users by metadata and ids": {
 			email:    "All",
@@ -169,6 +172,7 @@ func TestRetrieveAll(t *testing.T) {
 			size:     0,
 			total:    nUsers,
 			metadata: wrongMeta,
+			ids:      ids,
 		},
 		"retrieve users by wrong metadata and ids": {
 			email:    "All",
@@ -196,6 +200,15 @@ func TestRetrieveAll(t *testing.T) {
 			ids:      ids[0:5],
 			metadata: meta,
 		},
+		"retrieve all users from empty ids": {
+			email:    "All",
+			offset:   1,
+			limit:    5,
+			size:     0,
+			total:    nUsers,
+			ids:      []string{},
+			metadata: meta,
+		},
 	}
 	for desc, tc := range cases {
 		page, err := userRepo.RetrieveAll(context.Background(), tc.offset, tc.limit, tc.ids, tc.email, tc.metadata)