Java: avoid exceptions on bad javadoc html (IJ-CR-142291)

GitOrigin-RevId: 40fe350fab9354863141929cd135a5f2d0393fc2

java/java-analysis-impl/src/com/siyeh/ig/migration/MarkdownDocumentationCommentsMigrationInspection.java

@@ -153,13 +153,15 @@ final class MarkdownDocumentationCommentsMigrationInspection extends BaseInspect
             continue;
           }
           else if (c == '>') {
-            String name = html.substring(tag + (endTag ? 2 : 1), (html.charAt(i-1) == '/') ? i - 1 : i).trim().toLowerCase(Locale.ENGLISH);
+            int start = tag + (endTag ? 2 : 1);
+            int end = (!endTag && html.charAt(i - 1) == '/') ? i - 1 : i;
+            String name = html.substring(start, end).trim().toLowerCase(Locale.ENGLISH);
             if ("li".equals(name)) {
               if (endTag) {
                 inList = false;
               }
               else {
-                if ("    ".equals(result.substring(result.length() - 4))) {
+                if (result.length() > 4 && "    ".equals(result.substring(result.length() - 4))) {
                   result.delete(result.length() - 4, result.length());
                 }
                 result.append("  - ");

java/java-tests/testData/ig/com/siyeh/igtest/migration/markdown_documentation_comments_migration/MarkdownDocumentationCommentsMigration.after.java

@@ -347,4 +347,17 @@ interface Nothing {}
 /// If **at least** one element has priority, elements would be prioritized. No priority will be used otherwise
 ///
 /// @author Ilya.Kazakevich
-final class LookupWithIndentsBuilder {}
+final class LookupWithIndentsBuilder {
+
+  /// # 
+  /// Returns a hash code value for the object. This method is
+  /// supported for the benefit of hash tables such as those provided by
+  /// [java.util.HashMap].</>
+  public int hashCode() {
+    return 1;
+  }
+
+  ///   - one
+  ///   - two
+  void x() {}
+}

java/java-tests/testData/ig/com/siyeh/igtest/migration/markdown_documentation_comments_migration/MarkdownDocumentationCommentsMigration.java

@@ -363,4 +363,21 @@ interface Nothing {}
  *
  * @author Ilya.Kazakevich
  */
-final class LookupWithIndentsBuilder {}
+final class LookupWithIndentsBuilder {
+
+  <warning descr="Javadoc comment can be Markdown documentation comment">/**</warning>
+   * <h1>
+   * Returns a hash code value for the object. This method is
+   * supported for the benefit of hash tables such as those provided by
+   * {@link java.util.HashMap}.</>
+   */
+  public int hashCode() {
+    return 1;
+  }
+
+  <warning descr="Javadoc comment can be Markdown documentation comment">/**</warning>
+   * <li>one</li>
+   * <li>two</li>
+   */
+  void x() {}
+}