Merge branch 'ph/326904/fixSquashBeingReset' into 'master'

Fixes polling in ready to merge overwriting local state

See merge request gitlab-org/gitlab!58636

app/assets/javascripts/vue_merge_request_widget/components/states/ready_to_merge.vue

@@ -54,11 +54,7 @@ export default {
       },
       manual: true,
       result({ data }) {
-        this.state = {
-          ...data.project.mergeRequest,
-          mergeRequestsFfOnlyEnabled: data.project.mergeRequestsFfOnlyEnabled,
-          onlyAllowMergeIfPipelineSucceeds: data.project.onlyAllowMergeIfPipelineSucceeds,
-        };
+        if (Object.keys(this.state).length === 0) {
           this.removeSourceBranch =
             data.project.mergeRequest.shouldRemoveSourceBranch ||
             data.project.mergeRequest.forceRemoveSourceBranch ||
@@ -67,9 +63,16 @@ export default {
           this.squashBeforeMerge = data.project.mergeRequest.squashOnMerge;
           this.isSquashReadOnly = data.project.squashReadOnly;
           this.squashCommitMessage = data.project.mergeRequest.defaultSquashCommitMessage;
+        }
+
+        this.state = {
+          ...data.project.mergeRequest,
+          mergeRequestsFfOnlyEnabled: data.project.mergeRequestsFfOnlyEnabled,
+          onlyAllowMergeIfPipelineSucceeds: data.project.onlyAllowMergeIfPipelineSucceeds,
+        };
         this.loading = false;
 
-        if (this.state.mergeTrainsCount !== null) {
+        if (this.state.mergeTrainsCount !== null && this.state.mergeTrainsCount !== undefined) {
           this.initPolling();
         }
       },