8288545: Missing space in error message

Reviewed-by: hannesw

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

@@ -978,11 +978,15 @@ public Content seeTagToContent(Element element, DocTree see, TagletWriterImpl.Co
         String tagName = ch.getTagName(see);
 
         String seeText = utils.normalizeNewlines(ch.getText(see)).toString();
+        String refText;
         List<? extends DocTree> label;
         switch (kind) {
-            case LINK, LINK_PLAIN ->
+            case LINK, LINK_PLAIN -> {
                 // {@link[plain] reference label...}
-                label = ((LinkTree) see).getLabel();
+                LinkTree lt = (LinkTree) see;
+                refText = lt.getReference().toString();
+                label = lt.getLabel();
+            }
 
             case SEE -> {
                 List<? extends DocTree> ref = ((SeeTree) see).getReference();
@@ -998,6 +1002,7 @@ public Content seeTagToContent(Element element, DocTree see, TagletWriterImpl.Co
                     }
                     case REFERENCE -> {
                         // @see reference label...
+                        refText = ref.get(0).toString();
                         label = ref.subList(1, ref.size());
                     }
                     case ERRONEOUS -> {
@@ -1058,7 +1063,7 @@ public Content seeTagToContent(Element element, DocTree see, TagletWriterImpl.Co
                         messages.warning(ch.getDocTreePath(see),
                                 "doclet.see.class_or_package_not_found",
                                 "@" + tagName,
-                                seeText);
+                                refText);
                     }
                     return invalidTagOutput(resources.getText("doclet.tag.invalid", tagName),
                             Optional.of(labelContent.isEmpty() ? text: labelContent));
@@ -1112,7 +1117,7 @@ public Content seeTagToContent(Element element, DocTree see, TagletWriterImpl.Co
                     if (!configuration.isDocLintReferenceGroupEnabled()) {
                         messages.warning(
                                 ch.getDocTreePath(see), "doclet.see.class_or_package_not_found",
-                                tagName, seeText);
+                                tagName, refText);
                     }
                 }
             }

test/langtools/jdk/javadoc/doclet/testLinkTaglet/TestLinkNotFound.java

@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2022, 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      8288545
+ * @summary  Missing space in error message
+ * @library  /tools/lib ../../lib
+ * @modules  jdk.javadoc/jdk.javadoc.internal.tool
+ * @build    toolbox.ToolBox javadoc.tester.*
+ * @run main TestLinkNotFound
+ */
+
+import javadoc.tester.JavadocTester;
+import toolbox.ToolBox;
+
+import java.nio.file.Path;
+
+public class TestLinkNotFound extends JavadocTester {
+
+    public static void main(String... args) throws Exception {
+        TestLinkNotFound tester = new TestLinkNotFound();
+        tester.runTests();
+    }
+
+    ToolBox tb = new ToolBox();
+
+    @Test
+    public void test(Path base) throws Exception {
+        Path src = base.resolve("src");
+        tb.writeJavaFiles(src,
+                """
+                    /**
+                     * Comment.
+                     * {@link nowhere label}
+                     */
+                    public class C{ }
+                    """);
+
+        javadoc("-d", base.resolve("api").toString(),
+                "-Xdoclint:none",
+                "-Werror",
+                "-sourcepath", src.toString(),
+                src.resolve("C.java").toString());
+        checkExit(Exit.ERROR);
+
+        // the use of '\n' in the following check implies that the label does not appear after the reference
+        checkOutput(Output.OUT, true,
+                "reference not found: nowhere\n");
+    }
+}