Revert "Support single String argument for varargs invocations in SpEL"

This reverts commit d33f66d.

See gh-33013
See gh-33189

spring-expression/src/main/java/org/springframework/expression/spel/support/ReflectionHelper.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -298,11 +298,11 @@ static boolean convertArguments(TypeConverter converter, Object[] arguments, Exe
 						conversionOccurred = true;
 					}
 				}
-				// If the argument type is assignable to the varargs component type, there is no need to
+				// If the argument type is equal to the varargs element type, there is no need to
 				// convert it or wrap it in an array. For example, using StringToArrayConverter to
 				// convert a String containing a comma would result in the String being split and
 				// repackaged in an array when it should be used as-is.
-				else if (!sourceType.isAssignableTo(targetType.getElementTypeDescriptor())) {
+				else if (!sourceType.equals(targetType.getElementTypeDescriptor())) {
 					arguments[varargsPosition] = converter.convertValue(argument, sourceType, targetType);
 				}
 				// Possible outcomes of the above if-else block:

spring-expression/src/test/java/org/springframework/expression/spel/MethodInvocationTests.java

@@ -294,50 +294,6 @@ public void testVarargsInvocation03() {
 		evaluate("aVarargsMethod3('foo', 'bar,baz')", "foo-bar,baz", String.class);
 	}
 
-	@Test  // gh-33013
-	void testVarargsWithObjectArrayType() {
-		// Calling 'public String formatObjectVarargs(String format, Object... args)' -> String.format(format, args)
-
-		// No var-args and no conversion necessary
-		evaluate("formatObjectVarargs('x')", "x", String.class);
-
-		// No var-args but conversion necessary
-		evaluate("formatObjectVarargs(9)", "9", String.class);
-
-		// No conversion necessary
-		evaluate("formatObjectVarargs('x -> %s', '')", "x -> ", String.class);
-		evaluate("formatObjectVarargs('x -> %s', ' ')", "x ->  ", String.class);
-		evaluate("formatObjectVarargs('x -> %s', 'a')", "x -> a", String.class);
-		evaluate("formatObjectVarargs('x -> %s %s %s', 'a', 'b', 'c')", "x -> a b c", String.class);
-		evaluate("formatObjectVarargs('x -> %s', new Object[]{''})", "x -> ", String.class);
-		evaluate("formatObjectVarargs('x -> %s', new Object[]{' '})", "x ->  ", String.class);
-		evaluate("formatObjectVarargs('x -> %s', new Object[]{'a'})", "x -> a", String.class);
-		evaluate("formatObjectVarargs('x -> %s %s %s', new Object[]{'a', 'b', 'c'})", "x -> a b c", String.class);
-
-		// The following assertions were cherry-picked from 6.1.x; however, they are expected
-		// to fail on 6.0.x and 5.3.x, since gh-32704 (Support varargs invocations in SpEL for
-		// varargs array subtype) was not backported.
-		// evaluate("formatObjectVarargs('x -> %s', new String[]{''})", "x -> ", String.class);
-		// evaluate("formatObjectVarargs('x -> %s', new String[]{' '})", "x ->  ", String.class);
-		// evaluate("formatObjectVarargs('x -> %s', new String[]{'a'})", "x -> a", String.class);
-		// evaluate("formatObjectVarargs('x -> %s %s %s', new String[]{'a', 'b', 'c'})", "x -> a b c", String.class);
-
-		// Conversion necessary
-		evaluate("formatObjectVarargs('x -> %s %s', 2, 3)", "x -> 2 3", String.class);
-		evaluate("formatObjectVarargs('x -> %s %s', 'a', 3.0d)", "x -> a 3.0", String.class);
-
-		// Individual string contains a comma with multiple varargs arguments
-		evaluate("formatObjectVarargs('foo -> %s %s', ',', 'baz')", "foo -> , baz", String.class);
-		evaluate("formatObjectVarargs('foo -> %s %s', 'bar', ',baz')", "foo -> bar ,baz", String.class);
-		evaluate("formatObjectVarargs('foo -> %s %s', 'bar,', 'baz')", "foo -> bar, baz", String.class);
-
-		// Individual string contains a comma with single varargs argument.
-		evaluate("formatObjectVarargs('foo -> %s', ',')", "foo -> ,", String.class);
-		evaluate("formatObjectVarargs('foo -> %s', ',bar')", "foo -> ,bar", String.class);
-		evaluate("formatObjectVarargs('foo -> %s', 'bar,')", "foo -> bar,", String.class);
-		evaluate("formatObjectVarargs('foo -> %s', 'bar,baz')", "foo -> bar,baz", String.class);
-	}
-
 	@Test
 	public void testVarargsOptionalInvocation() {
 		// Calling 'public String optionalVarargsMethod(Optional<String>... values)'

spring-expression/src/test/java/org/springframework/expression/spel/SpelReproTests.java

@@ -66,7 +66,6 @@
 import static org.assertj.core.api.Assertions.assertThatException;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
-import static org.assertj.core.api.InstanceOfAssertFactories.list;
 
 /**
  * Reproduction tests cornering various reported SpEL issues.
@@ -1443,20 +1442,14 @@ void SPR12502() {
 		assertThat(expression.getValue(new NamedUser())).isEqualTo(NamedUser.class.getName());
 	}
 
-	@Test  // gh-17127, SPR-12522
-	void arraysAsListWithNoArguments() {
-		SpelExpressionParser parser = new SpelExpressionParser();
-		Expression expression = parser.parseExpression("T(java.util.Arrays).asList()");
-		List<?> value = expression.getValue(List.class);
-		assertThat(value).isEmpty();
-	}
-
-	@Test  // gh-33013
-	void arraysAsListWithSingleEmptyStringArgument() {
+	@Test
+	@SuppressWarnings("rawtypes")
+	void SPR12522() {
 		SpelExpressionParser parser = new SpelExpressionParser();
 		Expression expression = parser.parseExpression("T(java.util.Arrays).asList('')");
-		List<?> value = expression.getValue(List.class);
-		assertThat(value).asInstanceOf(list(String.class)).containsExactly("");
+		Object value = expression.getValue();
+		assertThat(value).isInstanceOf(List.class);
+		assertThat(((List) value).isEmpty()).isTrue();
 	}
 
 	@Test

spring-expression/src/test/java/org/springframework/expression/spel/testresources/Inventor.java

@@ -213,11 +213,6 @@ public String aVarargsMethod3(String str1, String... strings) {
 		return str1 + "-" + String.join("-", strings);
 	}
 
-	public String formatObjectVarargs(String format, Object... args) {
-		return String.format(format, args);
-	}
-
-
 	public Inventor(String... strings) {
 	}