Fixed multiple discussions getting added to diff lines

Closes https://gitlab.com/gitlab-org/gitlab-ee/issues/8195

1 files changed, 9 insertions, 3 deletions

diff --git a/app/assets/javascripts/diffs/store/mutations.js b/app/assets/javascripts/diffs/store/mutations.js
index f0895661bf2..331fb052371 100644
--- a/app/assets/javascripts/diffs/store/mutations.js
+++ b/app/assets/javascripts/diffs/store/mutations.js
@@ -130,7 +130,7 @@ export default {
 
         if (file.highlighted_diff_lines) {
           file.highlighted_diff_lines = file.highlighted_diff_lines.map(line => {
-            if (lineCheck(line)) {
+            if (!line.discussions.some(({ id }) => discussion.id === id) && lineCheck(line)) {
               return {
                 ...line,
                 discussions: line.discussions.concat(discussion),
@@ -150,11 +150,17 @@ export default {
               return {
                 left: {
                   ...line.left,
-                  discussions: left ? line.left.discussions.concat(discussion) : [],
+                  discussions:
+                    left && !line.left.discussions.some(({ id }) => id === discussion.id)
+                      ? line.left.discussions.concat(discussion)
+                      : (line.left && line.left.discussions) || [],
                 },
                 right: {
                   ...line.right,
-                  discussions: right && !left ? line.right.discussions.concat(discussion) : [],
+                  discussions:
+                    right && !left && !line.right.discussions.some(({ id }) => id === discussion.id)
+                      ? line.right.discussions.concat(discussion)
+                      : (line.right && line.right.discussions) || [],
                 },
               };
             }