8267126: javadoc should show "line and caret" for diagnostics.

Reviewed-by: prappo

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/toolkit/WorkArounds.java

@@ -60,6 +60,7 @@
 import com.sun.tools.javac.comp.Env;
 import com.sun.tools.javac.model.JavacElements;
 import com.sun.tools.javac.util.Names;
+import com.sun.tools.javac.util.Options;
 
 import jdk.javadoc.internal.doclets.toolkit.util.Utils;
 import jdk.javadoc.internal.tool.ToolEnvironment;
@@ -536,4 +537,21 @@ public boolean isReflectivePreviewAPI(Element el) {
         return (sym.flags() & Flags.PREVIEW_REFLECTIVE) != 0;
     }
 
+    /**
+     * Returns whether or not to permit dynamically loaded components to access
+     * part of the javadoc internal API. The flag is the same (hidden) compiler
+     * option that allows javac plugins and annotation processors to access
+     * javac internal API.
+     *
+     * As with all workarounds, it is better to consider updating the public API,
+     * rather than relying on undocumented features like this, that may be withdrawn
+     * at any time, without notice.
+     *
+     * @return true if access is permitted to internal API
+     */
+    public boolean accessInternalAPI() {
+        Options compilerOptions = Options.instance(toolEnv.context);
+        return compilerOptions.isSet("accessInternalAPI");
+    }
+
 }

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/toolkit/taglets/TagletManager.java

@@ -185,6 +185,8 @@ public class TagletManager {
 
     private final String tagletPath;
 
+    private final BaseConfiguration configuration;
+
     /**
      * Constructs a new {@code TagletManager}.
      *
@@ -197,6 +199,7 @@ public TagletManager(BaseConfiguration configuration) {
         standardTagsLowercase = new HashSet<>();
         unseenCustomTags = new HashSet<>();
         allTaglets = new LinkedHashMap<>();
+        this.configuration = configuration;
         BaseOptions options = configuration.getOptions();
         this.nosince = options.noSince();
         this.showversion = options.showVersion();
@@ -250,6 +253,15 @@ public void addCustomTag(String classname, JavaFileManager fileManager) {
         try {
             ClassLoader tagClassLoader;
             tagClassLoader = fileManager.getClassLoader(TAGLET_PATH);
+            if (configuration.workArounds.accessInternalAPI()) {
+                Module thisModule = getClass().getModule();
+                Module tagletLoaderUnnamedModule = tagClassLoader.getUnnamedModule();
+                List<String> pkgs = List.of(
+                        "jdk.javadoc.doclet",
+                        "jdk.javadoc.internal.doclets.toolkit",
+                        "jdk.javadoc.internal.doclets.formats.html");
+                pkgs.forEach(p -> thisModule.addOpens(p, tagletLoaderUnnamedModule));
+            }
             Class<? extends jdk.javadoc.doclet.Taglet> customTagClass =
                     tagClassLoader.loadClass(classname).asSubclass(jdk.javadoc.doclet.Taglet.class);
             jdk.javadoc.doclet.Taglet instance = customTagClass.getConstructor().newInstance();

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

@@ -93,6 +93,7 @@
 import javax.tools.JavaFileManager.Location;
 import javax.tools.StandardLocation;
 
+import com.sun.source.doctree.BlockTagTree;
 import com.sun.source.doctree.DeprecatedTree;
 import com.sun.source.doctree.DocCommentTree;
 import com.sun.source.doctree.DocTree;
@@ -2632,10 +2633,10 @@ public List<? extends DocTree> getBlockTags(Element element, DocTree.Kind kind,
 
     public List<? extends DocTree> getBlockTags(Element element, Taglet taglet) {
         return getBlockTags(element, t -> {
-            if (taglet instanceof BaseTaglet bt) {
-                return bt.accepts(t);
-            } else if (t instanceof UnknownBlockTagTree tree) {
-                return tree.getTagName().equals(taglet.getName());
+            if (taglet instanceof BaseTaglet baseTaglet) {
+                return baseTaglet.accepts(t);
+            } else if (t instanceof BlockTagTree blockTagTree) {
+                return blockTagTree.getTagName().equals(taglet.getName());
             } else {
                 return false;
             }

src/jdk.javadoc/share/classes/jdk/javadoc/internal/tool/ElementsTable.java

@@ -567,7 +567,7 @@ private Set<ModuleElement> getModuleRequires(ModuleElement mdle, boolean onlyTra
             if (!isMandated(mdle, rd) && onlyTransitive == rd.isTransitive()) {
                 if (!haveModuleSources(dep)) {
                     if (!warnedNoSources.contains(dep)) {
-                        messager.printWarning(dep, "main.module_source_not_found", dep.getQualifiedName());
+                        messager.printWarningUsingKey(dep, "main.module_source_not_found", dep.getQualifiedName());
                         warnedNoSources.add(dep);
                     }
                 }