Remove continuation indent on typing '@' in JavaDoc

See IDEA-179426 Javadoc @param/@return tag after @param tag with description should not be indented

java/java-impl/src/com/intellij/codeInsight/editorActions/JavadocTypedHandler.java

@@ -49,10 +49,29 @@ public class JavadocTypedHandler extends TypedHandlerDelegate {
   @NotNull
   @Override
   public Result charTyped(char c, @NotNull Project project, @NotNull Editor editor, @NotNull PsiFile file) {
-    insertClosingTagIfNecessary(c, project, editor, file);
+    if (file instanceof PsiJavaFile &&
+        (insertClosingTagIfNecessary(c, project, editor, file) ||
+         adjustStartTagIndent(c, editor, file))) {
+      return Result.CONTINUE;
+    }
     return Result.CONTINUE;
   }
 
+  private static boolean adjustStartTagIndent(char c, @NotNull Editor editor, @NotNull PsiFile file) {
+    if (c == '@') {
+      final int offset = editor.getCaretModel().getOffset();
+      PsiElement currElement = file.findElementAt(offset);
+      if (currElement instanceof PsiWhiteSpace) {
+        PsiElement prev = currElement.getPrevSibling();
+        if (prev != null && prev.getNode().getElementType() == JavaDocTokenType.DOC_COMMENT_LEADING_ASTERISKS) {
+          editor.getDocument().replaceString(currElement.getTextRange().getStartOffset(), offset - 1, " ");
+          return true;
+        }
+      }
+    }
+    return false;
+  }
+
   /**
    * Checks if it's necessary to insert closing tag on typed character.
    * 
@@ -63,7 +82,7 @@ public class JavadocTypedHandler extends TypedHandlerDelegate {
    * @return          {@code true} if closing tag is inserted; {@code false} otherwise
    */
   private static boolean insertClosingTagIfNecessary(char c, @NotNull Project project, @NotNull Editor editor, @NotNull PsiFile file) {
-    if (c != CLOSE_TAG_SYMBOL || !CodeInsightSettings.getInstance().JAVADOC_GENERATE_CLOSING_TAG || !(file instanceof PsiJavaFile)) {
+    if (c != CLOSE_TAG_SYMBOL || !CodeInsightSettings.getInstance().JAVADOC_GENERATE_CLOSING_TAG) {
       return false;
     }
 

java/java-tests/testData/codeInsight/editorActions/javadocTypedHandler/docTagStart.java

@@ -0,0 +1,10 @@
+package com.company;
+
+public class Test {
+    /**
+     * @param a Description A
+     * @param b Description B
+     *          <caret>
+     */
+    void foo(int a, int b, int c) {}
+}

java/java-tests/testData/codeInsight/editorActions/javadocTypedHandler/docTagStart_after.java

@@ -0,0 +1,10 @@
+package com.company;
+
+public class Test {
+    /**
+     * @param a Description A
+     * @param b Description B
+     * @<caret>
+     */
+    void foo(int a, int b, int c) {}
+}

java/java-tests/testSrc/com/intellij/java/codeInsight/editorActions/JavadocTypedHandlerFunctionalTest.java

@@ -21,25 +21,29 @@ public class JavadocTypedHandlerFunctionalTest extends LightPlatformCodeInsightT
   private static final String BASE_PATH = "/codeInsight/editorActions/javadocTypedHandler/";
 
   public void testEmptyTag() {
-    doTest();
+    doTest('>');
   }
 
   public void testComment() {
-    doTest();
+    doTest('>');
   }
 
   public void testCodeTag() {
-    doTest();
+    doTest('>');
   }
   
   public void testTypeParam() {
-    doTest();
+    doTest('>');
   }
 
-  private void doTest() {
+  public void testDocTagStart() {
+    doTest('@');
+  }
+
+  private void doTest(char typedChar) {
     String testName = getTestName(true);
     configureByFile(BASE_PATH + testName + ".java");
-    type('>');
+    type(typedChar);
     checkResultByFile(BASE_PATH + testName + "_after.java");
   }