Java: fix SIOOBE in "Escape trailing whitespace characters"

GitOrigin-RevId: 1f975c570b0192a94b651e219b517f742b3b0ba0

java/java-impl-inspections/src/com/intellij/codeInspection/TrailingWhitespacesInTextBlockInspection.java

@@ -200,13 +200,13 @@ public final class TrailingWhitespacesInTextBlockInspection extends AbstractBase
           if (suffix.equals("\\{")) return result.append(line).toString();
           line = line.substring(0, line.length() - suffix.length());
         }
-        String transformed = lineTransformation.apply(line);
+        String transformed = line.isEmpty() ? line : lineTransformation.apply(line);
         if (transformed == null) return null;
         if (last && hasUnescapedLastQuote(transformed)) {
           result.append(transformed, 0, transformed.length() - 1).append("\\\"");
         }
         else if (transformed.isEmpty()) {
-          result.append((line.length() < indent) ? line : " ".repeat(indent));
+          result.append((line.length() < indent) ? line : line.substring(0, indent));
         } else {
           result.append(transformed);
         }

java/java-tests/testData/inspection/trailingWhitespacesInTextBlock/EmptyLine.after.java

@@ -0,0 +1,9 @@
+class EmptyLine {
+  
+  void x(int a) {
+    System.out.println(STR."""
+          a\na       "\{a}
+
+               \s""");
+  }
+}

java/java-tests/testData/inspection/trailingWhitespacesInTextBlock/EmptyLine.java

@@ -0,0 +1,9 @@
+class EmptyLine {
+  
+  void x(int a) {
+    System.out.println(STR."""
+          a\na       "\{a}
+
+          <warning descr="Trailing whitespace characters inside text block"><caret>      </warning>""");
+  }
+}

java/java-tests/testData/inspection/trailingWhitespacesInTextBlock/WithBlankLines.after.java

@@ -1,12 +1,12 @@
 class Foo {
   void test() {
     String colors = """
-    
+			 
     
 
        red
-    
-    
+				
+  		
 
        green
     

java/java-tests/testData/inspection/trailingWhitespacesInTextBlock/WithEndQuotes.after.java

@@ -28,5 +28,10 @@ class Foo {
                 \u005C \"""";
     String text14 = """
                 \u005C\u005C\u005C\u005C\"""";
+    String text15 = STR."""
+      "scary"\{}
+      "scary"\{}
+      "scary" \{}
+      """;
   }
 }

java/java-tests/testData/inspection/trailingWhitespacesInTextBlock/WithEndQuotes.java

@@ -28,5 +28,10 @@ class Foo {
                 <error descr="Illegal escape character in string literal">\u005C</error> "<warning descr="Trailing whitespace characters inside text block"> </warning>""";
     String text14 = """
                 \u005C\u005C\u005C\u005C"<warning descr="Trailing whitespace characters inside text block"> </warning>""";
+    String text15 = STR."""
+      "scary"\{}<warning descr="Trailing whitespace characters inside text block"> </warning>
+      "scary"\{} 
+      "scary" \{} 
+      """;
   }
 }

java/java-tests/testSrc/com/intellij/java/codeInspection/TrailingWhitespacesInTextBlockInspectionTest.java

@@ -12,6 +12,7 @@ public class TrailingWhitespacesInTextBlockInspectionTest extends LightJavaInspe
 
   public void testBadTextBlock() { doTest(); }
   public void testBlankLine() { doTestAll(); }
+  public void testEmptyLine() { doTestEscape(); }
   public void testEmptyLastLine() { doTestAll(); }
   public void testOneLineBlock() { doTestAll(); }
   public void testReplaceAtTheEnd() { doTestEscape(); }