[#2123] Fix zoom bug if zUser is undefined (#2126)

Fix error thrown when zUser is undefined

Currently, an error is thrown when zUser is defined in c-zoom.vue. This
might be caused by zFilterSearch containing a query that returns no
results. Though this happening through normal user interaction is rare
(editing URL, for example), RepoSense should handle this case
gracefully rather than throwing an error.

Let's fix this bug by resetting the zoom view if the error happens.

frontend/src/views/c-summary.vue

@@ -909,7 +909,9 @@ export default defineComponent({
       if (zIsMerged) {
         this.mergeGroupByIndex(filtered, 0);
       }
-      [[info.zUser]] = filtered;
+
+      if (filtered.length) [[info.zUser]] = filtered;
+
       info.zFileTypeColors = this.fileTypeColors;
       info.isRefreshing = false;
       this.$store.commit('updateTabZoomInfo', info);

frontend/src/views/c-zoom.vue

@@ -1,5 +1,5 @@
 <template lang="pug">
-#zoom
+#zoom(v-if="filteredUser")
   .panel-title
     span Commits Panel
   .toolbar--multiline(v-if="filteredUser.commits.length && totalCommitMessageBodyCount")
@@ -199,13 +199,13 @@ export default defineComponent({
       return (a: Commit, b: Commit) => (this.toReverseSortedCommits ? -1 : 1)
         * window.comparator(commitSortFunction)(a, b);
     },
-    filteredUser(): User {
+    filteredUser(): User | undefined {
       const {
         zUser, zSince, zUntil, zTimeFrame,
       } = this.info;
 
       if (!zUser) {
-        throw new Error('zUser is not defined');
+        return undefined;
       }
 
       const filteredUser: User = Object.assign({}, zUser);
@@ -242,11 +242,11 @@ export default defineComponent({
 
     selectedCommits(): Array<Commit> {
       if (this.isSelectAllChecked) {
-        return this.filteredUser.commits;
+        return this.filteredUser?.commits ?? [];
       }
 
       const commits = [] as Array<Commit>;
-      this.filteredUser.commits.forEach((commit) => {
+      this.filteredUser?.commits.forEach((commit) => {
         const filteredCommit = { ...commit };
         filteredCommit.commitResults = [];
         commit.commitResults.forEach((slice) => {
@@ -318,6 +318,12 @@ export default defineComponent({
     },
   },
   created() {
+    // return if filteredUser is undefined since it won't make sense to render zoom tab
+    // #zoom-tab is also rendered only if filteredUser is defined
+    if (!this.filteredUser) {
+      this.removeZoomHashes();
+      return;
+    }
     this.initiate();
     this.retrieveHashes();
     this.setInfoHash();
@@ -328,7 +334,6 @@ export default defineComponent({
 
   methods: {
     initiate() {
-      // This code crashes if info.zUser is not defined
       this.updateFileTypes();
       this.selectedFileTypes = this.fileTypes.slice();
     },
@@ -404,6 +409,8 @@ export default defineComponent({
     },
 
     updateFileTypes() {
+      if (!this.filteredUser) return;
+
       const commitsFileTypes = new Set<string>();
       this.filteredUser.commits.forEach((commit) => {
         commit.commitResults.forEach((slice) => {
@@ -499,6 +506,7 @@ export default defineComponent({
       window.removeHash('zFT');
       window.removeHash('zCST');
       window.removeHash('zRSC');
+      window.removeHash('zFR');
       window.encodeHash();
     },