i18n: don't create nested choices, escape special symbols in choice sides (IDEA-247804)

GitOrigin-RevId: dcb56f8bf352bc8f656edd85242be6b3c70af34d

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/i18nize/beforeGeneratedChoicePattern.java

@@ -1,5 +1,5 @@
 class MyTest {
   void f(boolean prefix){
-    String s = "Not a valid java identifier<caret> part in " + (prefix ? "prefix" : "suffix");
+    String s = "Not a valid java identifier<caret> part in " + (prefix ? "prefix" : "<br/>suffix");
   }
 }

java/java-tests/testSrc/com/intellij/java/codeInsight/daemon/quickFix/I18nizeTest.java

@@ -106,7 +106,7 @@ public class I18nizeTest extends LightJavaCodeInsightTestCase {
     UStringConcatenationsFacade concatenation = UStringConcatenationsFacade.createFromTopConcatenation(enclosingStringLiteral);
     assertNotNull(concatenation);
     ArrayList<UExpression> args = new ArrayList<>();
-    Assert.assertEquals("Not a valid java identifier part in {0, choice, 0#prefix|1#suffix}", JavaI18nUtil.buildUnescapedFormatString(concatenation, args, getProject()));
+    Assert.assertEquals("Not a valid java identifier part in {0, choice, 0#prefix|1#'<'br/'>'suffix}", JavaI18nUtil.buildUnescapedFormatString(concatenation, args, getProject()));
     assertSize(1, args);
     assertEquals("prefix ? 0 : 1", args.get(0).getSourcePsi().getText());
   }

plugins/java-i18n/src/com/intellij/codeInspection/i18n/JavaI18nUtil.java

@@ -467,7 +467,7 @@ public final class JavaI18nUtil extends I18nUtil {
           }
         }
       }
-      else if (!addChoicePattern(expression, formatParameters, project, result)) {
+      else if (nested || !addChoicePattern(expression, formatParameters, project, result)) {
         result.append("{").append(formatParameters.size()).append("}");
         formatParameters.add(expression);
       }
@@ -542,7 +542,7 @@ public final class JavaI18nUtil extends I18nUtil {
         formatParameters.add(expression);
       }
     }
-    return elseStr;
+    return elseStr.replaceAll("([<>|#])", "'$1'");
   }
 
   @NotNull