8351332: Line breaks in search tag descriptions corrupt JSON search index

Reviewed-by: hannesw, liach

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/HtmlDocletWriter.java

@@ -1890,7 +1890,7 @@ public abstract class HtmlDocletWriter {
         }
         // Generate index item
         if (!headingContent.isEmpty() && configuration.indexBuilder != null) {
-            String tagText = headingContent.replaceAll("\\s+", " ");
+            String tagText = utils.normalizeWhitespace(headingContent);
             IndexItem item = IndexItem.of(element, node, tagText,
                     getTagletWriterInstance(context).getHolderName(element),
                     "",

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/taglets/IndexTaglet.java

@@ -58,10 +58,10 @@ public class IndexTaglet extends BaseTaglet {
         if (tagText.charAt(0) == '"' && tagText.charAt(tagText.length() - 1) == '"') {
             tagText = tagText.substring(1, tagText.length() - 1);
         }
-        tagText = tagText.replaceAll("\\s+", " ");
+        tagText = utils.normalizeWhitespace(tagText);
 
         Content desc = tagletWriter.htmlWriter.commentTagsToContent(element, indexTree.getDescription(), context.within(indexTree));
-        String descText = extractText(desc);
+        String descText = utils.normalizeWhitespace(extractText(desc));
 
         return tagletWriter.createAnchorAndSearchIndex(element, tagText, descText, tag);
     }

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/taglets/SpecTaglet.java

@@ -123,7 +123,7 @@ public class SpecTaglet extends BaseTaglet implements InheritableTaglet {
         List<? extends DocTree> specTreeLabel = specTree.getTitle();
         Content label = htmlWriter.commentTagsToContent(holder, specTreeLabel, tagletWriter.context.isFirstSentence);
         return getExternalSpecContent(holder, specTree, specTreeURL,
-                textOf(label).replaceAll("\\s+", " "), label);
+                utils.normalizeWhitespace(textOf(label)), label);
     }
 
     // this is here, for now, but might be a useful addition elsewhere,

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/toolkit/util/Utils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -1132,6 +1132,15 @@ public class Utils {
         return result.toString();
     }
 
+    /**
+     * Replaces each group of one or more whitespace characters with a single canonical space
+     * @param s the string to be normalized
+     * @return normalized string
+     */
+    public String normalizeWhitespace(String s) {
+        return s.replaceAll("\\s+", " ");
+    }
+
     /**
      * Returns a locale independent lower cased String. That is, it
      * always uses US locale, this is a clone of the one in StringUtils.

test/langtools/jdk/javadoc/doclet/testIndexLineBreaks/TestIndexLineBreaks.java

@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8351332
+ * @summary Line breaks in the description of `{@index}` tags may corrupt JSON search index
+ * @library /tools/lib ../../lib
+ * @modules jdk.javadoc/jdk.javadoc.internal.tool
+ * @build toolbox.ToolBox javadoc.tester.*
+ * @run main TestIndexLineBreaks
+ */
+
+import java.io.IOException;
+import java.nio.file.Path;
+
+import javadoc.tester.JavadocTester;
+import toolbox.ToolBox;
+
+public class TestIndexLineBreaks extends JavadocTester {
+
+    public static void main(String... args) throws Exception {
+        var tester = new TestIndexLineBreaks ();
+        tester.runTests();
+    }
+
+    ToolBox tb = new ToolBox();
+
+    @Test
+    public void test() throws IOException {
+        Path src = Path.of("src");
+        tb.writeJavaFiles(src,
+                """
+                            package p;
+                            public interface I {
+                                /**
+                                 *
+                                 * The {@index "phrase1
+                                 * phrase2" description1
+                                 * description2 }
+                                 */
+                                int a();
+                            }
+                        """);
+
+        javadoc("-d",
+                "out",
+                "-sourcepath",
+                src.toString(),
+                "p");
+
+        checkExit(Exit.OK);
+
+        checkOutput("tag-search-index.js", true,
+                """
+                        {"l":"phrase1 phrase2","h":"p.I.a()","d":"description1 description2 ","u":"p/I.html#phrase1phrase2"},{"l":"Search Tags","h":"","k":"18","u":"search-tags.html"}""");
+
+        checkOutput("tag-search-index.js", false,
+                """
+                        {"l":"phrase1 phrase2","h":"p.I.a()","d":"description1
+                        description2 ","u":"p/I.html#phrase1phrase2"},{"l":"Search Tags","h":"","k":"18","u":"search-tags.html"}""");
+    }
+}