fix: Address voidmatcha review feedback + UI improvements

- Display paragraph title in search results (Angular + Classic UI)
- Dark mode: replace hardcoded colors with themeMixin design tokens
- Prettier: reformat tablesText chain to multi-line
- Hybrid search: add keyword boost so exact matches surface even when
  embedding similarity is low (e.g. searching "TETRIS" finds SQL
  containing TETRIS_VIDEO_SINGLE_MEDIA)
- Highlight query terms in semantic search snippets using <B> tags
- Make entire search result card clickable (preserves text selection)
- Deep link: wire term query param to highlight matches in editor
- Search history: persist recent searches via localStorage + datalist
- Fix InterpreterFactory NPE when interpreter group is not installed

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Kalyan Kanuri

zeppelin-server/src/main/java/org/apache/zeppelin/interpreter/InterpreterFactory.java

@@ -44,6 +44,10 @@ public Interpreter getInterpreter(String replName,
       // Get the default interpreter of the defaultInterpreterSetting
       InterpreterSetting defaultSetting =
           interpreterSettingManager.getByName(executionContext.getDefaultInterpreterGroup());
+      if (defaultSetting == null) {
+        throw new InterpreterNotFoundException("No interpreter found for group: "
+            + executionContext.getDefaultInterpreterGroup());
+      }
       return defaultSetting.getDefaultInterpreter(executionContext);
     }
 

zeppelin-server/src/main/java/org/apache/zeppelin/search/EmbeddingSearch.java

@@ -36,6 +36,7 @@
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.util.ArrayList;
+import java.util.Locale;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -106,6 +107,12 @@ public class EmbeddingSearch extends SearchService {
    * and cannot promote semantically unrelated results past {@link #MIN_SIMILARITY}.
    */
   private static final float TABLE_BOOST = 0.05f;
+  /**
+   * Additive score boost when the query string appears literally in the indexed text.
+   * Ensures exact keyword matches surface even when the embedding similarity is low
+   * (e.g. searching "TETRIS" in SQL containing TETRIS_VIDEO_SINGLE_MEDIA).
+   */
+  private static final float KEYWORD_BOOST = 0.30f;
   /**
    * Fraction of the top table's weight used as the cutoff for "relevant" tables in Phase 1
    * of {@link #query(String)}. Tables below this share are dropped from the boost set
@@ -380,6 +387,25 @@ private static float cosineSimilarity(float[] a, float[] b) {
     return dot;
   }
 
+  /**
+   * Wrap occurrences of each query word in {@code <B>} tags (case-insensitive)
+   * to match Lucene's highlighting convention.
+   */
+  static String highlightTerms(String text, String queryStr) {
+    if (StringUtils.isBlank(text) || StringUtils.isBlank(queryStr)) {
+      return text;
+    }
+    String[] words = queryStr.split("\\s+");
+    for (String word : words) {
+      if (word.isEmpty()) {
+        continue;
+      }
+      String escaped = Pattern.quote(word);
+      text = text.replaceAll("(?i)(" + escaped + ")", "<B>$1</B>");
+    }
+    return text;
+  }
+
   // ---- Text extraction ----
 
   /**
@@ -494,13 +520,18 @@ public List<Map<String, String>> query(String queryStr) {
     }
 
     float[] queryEmbedding = embed(queryStr);
+    String queryLower = queryStr.toLowerCase(Locale.ROOT);
 
     // Phase 1: find top-N results and discover relevant tables
     List<Map.Entry<String, Float>> scored = new ArrayList<>();
     indexLock.readLock().lock();
     try {
       for (Map.Entry<String, IndexEntry> entry : index.entrySet()) {
         float sim = cosineSimilarity(queryEmbedding, entry.getValue().embedding);
+        IndexEntry ie = entry.getValue();
+        if (ie.text != null && ie.text.toLowerCase(Locale.ROOT).contains(queryLower)) {
+          sim += KEYWORD_BOOST;
+        }
         scored.add(Map.entry(entry.getKey(), sim));
       }
     } finally {
@@ -559,13 +590,15 @@ public List<Map<String, String>> query(String queryStr) {
           output = output.substring(0, 300);
         }
       }
+      String snippet = highlightTerms(entry.text, queryStr);
+      String highlightedTitle = highlightTerms(title, queryStr);
       candidates.add(Map.entry(ImmutableMap.<String, String>builder()
           .put("id", docId)
           .put("name", entry.noteName != null ? entry.noteName : "")
-          .put("snippet", entry.text)
+          .put("snippet", snippet)
           .put("text", entry.text)
-          .put("header", title)
-          .put("title", title)
+          .put("header", highlightedTitle)
+          .put("title", highlightedTitle)
           .put("tables", tables)
           .put("output", output)
           .build(), sim));

zeppelin-web-angular/src/app/pages/workspace/notebook-search/result-item/result-item.component.html

@@ -10,13 +10,12 @@
   ~ limitations under the License.
   -->
 
-<nz-card [nzTitle]="titleTemplateRef">
-  <ng-template #titleTemplateRef>
-    <div class="result-header">
-      <a [routerLink]="routerLink" [queryParams]="queryParams">{{ displayName }}</a>
-      <span *ngIf="interpreter" class="badge" [ngClass]="interpreter">{{ interpreter }}</span>
-    </div>
-  </ng-template>
+<nz-card class="result-card" (click)="navigate($event)">
+  <div class="result-header">
+    <a [routerLink]="routerLink" [queryParams]="queryParams" (click)="$event.stopPropagation()">{{ displayName }}</a>
+    <span *ngIf="interpreter" class="badge" [ngClass]="interpreter">{{ interpreter }}</span>
+  </div>
+  <div *ngIf="titleHtml" class="title-block" [innerHTML]="titleHtml"></div>
   <div *ngIf="codeHtml" class="code-block">
     <pre [innerHTML]="codeHtml"></pre>
   </div>

zeppelin-web-angular/src/app/pages/workspace/notebook-search/result-item/result-item.component.less

@@ -10,11 +10,18 @@
  * limitations under the License.
  */
 
+@import 'theme-mixin';
+
 :host {
   display: block;
   margin-bottom: 12px;
 }
 
+.result-card {
+  cursor: pointer;
+  user-select: text;
+}
+
 .result-header {
   display: flex;
   align-items: center;
@@ -25,39 +32,18 @@
   font-size: 11px;
   padding: 1px 8px;
   border-radius: 10px;
-  background: #e8e8e8;
-  color: #666;
-}
-
-.badge.sql {
-  background: #e6f7e6;
-  color: #389e0d;
-}
-
-.badge.python, .badge.pyspark {
-  background: #fff7e6;
-  color: #d48806;
-}
-
-.badge.md {
-  background: #e6f0ff;
-  color: #1890ff;
 }
 
 .code-block {
-  background: #f6f8fa;
-  border: 1px solid #e1e4e8;
   border-radius: 6px;
   padding: 10px 12px;
   margin-bottom: 8px;
   overflow-x: auto;
 
   pre {
     margin: 0;
-    font-family: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
     font-size: 12px;
     line-height: 1.5;
-    color: #24292e;
     white-space: pre-wrap;
     word-break: break-word;
     max-height: 200px;
@@ -66,34 +52,88 @@
 }
 
 .output-block {
-  background: #fafbfc;
-  border-left: 3px solid #d1d5da;
   border-radius: 0 4px 4px 0;
   padding: 8px 12px;
   margin-bottom: 8px;
   overflow-x: auto;
 
   pre {
     margin: 0;
-    font-family: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
     font-size: 11px;
     line-height: 1.4;
-    color: #586069;
     white-space: pre-wrap;
     word-break: break-word;
     max-height: 120px;
     overflow-y: auto;
   }
 }
 
+.title-block {
+  font-size: 12px;
+  padding: 4px 0;
+  margin-bottom: 4px;
+}
+
 .tables-block {
   font-size: 12px;
-  color: #22863a;
   padding: 4px 0;
 }
 
 mark {
-  background-color: #fff3bf;
   padding: 0 1px;
   border-radius: 2px;
 }
+
+.themeMixin({
+  .badge {
+    background: @background-color-base;
+    color: @text-color-secondary;
+  }
+
+  .badge.sql {
+    background: @green-1;
+    color: @green-7;
+  }
+
+  .badge.python, .badge.pyspark {
+    background: @gold-1;
+    color: @gold-7;
+  }
+
+  .badge.md {
+    background: @blue-1;
+    color: @blue-6;
+  }
+
+  .code-block {
+    background: @background-color-light;
+    border: 1px solid @border-color-split;
+
+    pre {
+      font-family: @code-family;
+      color: @text-color;
+    }
+  }
+
+  .output-block {
+    background: @background-color-light;
+    border-left: 3px solid @border-color-base;
+
+    pre {
+      font-family: @code-family;
+      color: @text-color-secondary;
+    }
+  }
+
+  .title-block {
+    color: @text-color-secondary;
+  }
+
+  .tables-block {
+    color: @green-7;
+  }
+
+  mark {
+    background-color: @gold-1;
+  }
+});

zeppelin-web-angular/src/app/pages/workspace/notebook-search/result-item/result-item.component.ts

@@ -11,7 +11,7 @@
  */
 
 import { ChangeDetectionStrategy, Component, Input, OnChanges, SimpleChanges } from '@angular/core';
-import { ActivatedRoute } from '@angular/router';
+import { ActivatedRoute, Router } from '@angular/router';
 import { NotebookSearchResultItem } from '@zeppelin/interfaces';
 
 @Component({
@@ -29,18 +29,31 @@ export class NotebookSearchResultItemComponent implements OnChanges {
   codeHtml = '';
   outputText = '';
   tablesText = '';
+  titleHtml = '';
   interpreter = '';
 
-  constructor(private router: ActivatedRoute) {}
+  constructor(
+    private route: ActivatedRoute,
+    private router: Router
+  ) {}
 
   ngOnChanges(changes: SimpleChanges): void {
     if (changes.result) {
       this.parseResult();
     }
   }
 
+  navigate(event: MouseEvent): void {
+    const selection = window.getSelection();
+    if (selection && selection.toString().length > 0) {
+      return;
+    }
+    event.preventDefault();
+    this.router.navigate(this.routerLink, { queryParams: this.queryParams });
+  }
+
   private parseResult(): void {
-    const term = this.router.snapshot.params.queryStr;
+    const term = this.route.snapshot.params.queryStr;
     const listOfId = this.result.id.split('/');
     const [noteId, hasParagraph, paragraph] = listOfId;
     if (!hasParagraph) {
@@ -58,8 +71,15 @@ export class NotebookSearchResultItemComponent implements OnChanges {
     this.codeText = snippet.replace(/<\/?B>/gi, '');
     this.interpreter = this.detectInterpreter(this.codeText);
 
+    const title = this.result.title || '';
+    this.titleHtml = title.replace(/<B>/gi, '<mark>').replace(/<\/B>/gi, '</mark>');
+
     const tables = this.result.tables || '';
-    this.tablesText = tables.trim().split(/\s+/).filter(t => t).join(', ');
+    this.tablesText = tables
+      .trim()
+      .split(/\s+/)
+      .filter(t => t)
+      .join(', ');
     this.outputText = this.result.output || '';
   }
 

zeppelin-web-angular/src/app/pages/workspace/notebook/notebook.component.ts

@@ -23,7 +23,7 @@ import { Title } from '@angular/platform-browser';
 import { ActivatedRoute, Router } from '@angular/router';
 import { isNil } from 'lodash';
 import { Subject } from 'rxjs';
-import { distinctUntilKeyChanged, map, startWith, takeUntil } from 'rxjs/operators';
+import { distinctUntilKeyChanged, startWith, takeUntil } from 'rxjs/operators';
 
 import { NzResizeEvent } from 'ng-zorro-antd/resizable';
 
@@ -422,14 +422,12 @@ export class NotebookComponent extends MessageListenersManager implements OnInit
 
   ngOnInit() {
     this.activatedRoute.queryParamMap
-      .pipe(
-        startWith(this.activatedRoute.snapshot.queryParamMap),
-        takeUntil(this.destroy$),
-        map(data => data.get('paragraph'))
-      )
-      .subscribe(id => {
+      .pipe(startWith(this.activatedRoute.snapshot.queryParamMap), takeUntil(this.destroy$))
+      .subscribe(params => {
+        const id = params.get('paragraph');
         this.onParagraphSelect(id);
         this.onParagraphScrolled(id);
+        this.onParagraphSearch(params.get('term') || '');
       });
     this.activatedRoute.params.pipe(takeUntil(this.destroy$), distinctUntilKeyChanged('noteId')).subscribe(() => {
       this.noteVarShareService.clear();

zeppelin-web-angular/src/app/share/header/header.component.html

@@ -78,8 +78,18 @@
   </div>
   <div class="search">
     <nz-input-group [nzPrefixIcon]="'search'">
-      <input type="text" nz-input placeholder="Search" (keyup.enter)="onSearch()" [(ngModel)]="queryStr" />
+      <input
+        type="text"
+        nz-input
+        placeholder="Search"
+        list="search-history"
+        (keyup.enter)="onSearch()"
+        [(ngModel)]="queryStr"
+      />
     </nz-input-group>
+    <datalist id="search-history">
+      <option *ngFor="let item of searchHistory" [value]="item"></option>
+    </datalist>
   </div>
   <zeppelin-theme-toggle class="theme-toggle"></zeppelin-theme-toggle>
 </div>