Polish contribution and SimpleCommandLineArgs-related code

Closes gh-34282

spring-core/src/main/java/org/springframework/core/env/CommandLinePropertySource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -25,8 +25,7 @@ import org.springframework.util.StringUtils;
 /**
  * Abstract base class for {@link PropertySource} implementations backed by command line
  * arguments. The parameterized type {@code T} represents the underlying source of command
- * line options. For instance, {@link SimpleCommandLinePropertySource} uses  a String
+ * line options.
- * array.
  *
  * <h3>Purpose and General Usage</h3>
  *
@@ -259,10 +258,11 @@ public abstract class CommandLinePropertySource<T> extends EnumerablePropertySou
 	 * This implementation first checks to see if the name specified is the special
 	 * {@linkplain #setNonOptionArgsPropertyName(String) "non-option arguments" property},
 	 * and if so delegates to the abstract {@link #getNonOptionArgs()} method. If so
-	 * and the collection of non-option arguments is empty, this method returns {@code
+	 * and the collection of non-option arguments is empty, this method returns
-	 * null}. If not empty, it returns a comma-separated String of all non-option
+	 * {@code null}. If not empty, it returns a comma-separated String of all non-option
-	 * arguments. Otherwise, delegates to and returns the result of the abstract {@link
+	 * arguments. Otherwise, this method delegates to and returns a comma-separated String
-	 * #getOptionValues(String)} method.
+	 * of the results of the abstract {@link #getOptionValues(String)} method or
+	 * {@code null} if there are no such option values.
 	 */
 	@Override
 	@Nullable

spring-core/src/main/java/org/springframework/core/env/SimpleCommandLineArgsParser.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -28,8 +28,9 @@ package org.springframework.core.env;
  * <p>That is, options must be prefixed with "{@code --}" and may or may not
  * specify a value. If a value is specified, the name and value must be separated
  * <em>without spaces</em> by an equals sign ("="). The value may optionally be
- * an empty string. if the option is present and has multiple values (e. g. "--foo=bar --foo=baz"),
+ * an empty string. If an option is present multiple times with different values
-* the values are parsed as a collection.
+ * &mdash; for example, {@code --foo=bar --foo=baz} &mdash; all supplied values
+ * will be stored for the option.
  *
  * <h4>Valid examples of option arguments</h4>
  * <pre class="code">

spring-core/src/main/java/org/springframework/core/env/SimpleCommandLinePropertySource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -22,7 +22,8 @@ import org.springframework.lang.Nullable;
 import org.springframework.util.StringUtils;
 
 /**
- * {@link CommandLinePropertySource} implementation backed by a simple String array.
+ * {@link CommandLinePropertySource} implementation backed by an instance of
+ * {@link CommandLineArgs}.
  *
  * <h3>Purpose</h3>
  * <p>This {@code CommandLinePropertySource} implementation aims to provide the simplest
@@ -40,8 +41,9 @@ import org.springframework.util.StringUtils;
  * <p>That is, options must be prefixed with "{@code --}" and may or may not
  * specify a value. If a value is specified, the name and value must be separated
  * <em>without spaces</em> by an equals sign ("="). The value may optionally be
- * an empty string. if the option is present and has multiple values (e. g. "--foo=bar --foo=baz"),
+ * an empty string. If an option is present multiple times with different values
- * the values are parsed as a collection.
+ * &mdash; for example, {@code --foo=bar --foo=baz} &mdash; all supplied values
+ * will be stored for the option.
  *
  * <h4>Valid examples of option arguments</h4>
  * <pre class="code">

spring-core/src/test/java/org/springframework/core/env/SimpleCommandLineArgsParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -46,7 +46,7 @@ class SimpleCommandLineArgsParserTests {
 	void withSingleOptionAndNoValue() {
 		CommandLineArgs args = parser.parse("--o1");
 		assertThat(args.containsOption("o1")).isTrue();
-		assertThat(args.getOptionValues("o1")).isEqualTo(Collections.EMPTY_LIST);
+		assertThat(args.getOptionValues("o1")).isEmpty();
 	}
 
 	@Test
@@ -56,6 +56,20 @@ class SimpleCommandLineArgsParserTests {
 		assertThat(args.getOptionValues("o1")).containsExactly("v1");
 	}
 
+	@Test
+	void withRepeatedOptionAndSameValues() {
+		CommandLineArgs args = parser.parse("--o1=v1", "--o1=v1", "--o1=v1");
+		assertThat(args.containsOption("o1")).isTrue();
+		assertThat(args.getOptionValues("o1")).containsExactly("v1", "v1", "v1");
+	}
+
+	@Test
+	void withRepeatedOptionAndDifferentValues() {
+		CommandLineArgs args = parser.parse("--o1=v1", "--o1=v2", "--o1=v3");
+		assertThat(args.containsOption("o1")).isTrue();
+		assertThat(args.getOptionValues("o1")).containsExactly("v1", "v2", "v3");
+	}
+
 	@Test
 	void withMixOfOptionsHavingValueAndOptionsHavingNoValue() {
 		CommandLineArgs args = parser.parse("--o1=v1", "--o2");
@@ -95,17 +109,17 @@ class SimpleCommandLineArgsParserTests {
 	}
 
 	@Test
-	void assertOptionNamesIsUnmodifiable() {
+	void optionNamesSetIsUnmodifiable() {
 		CommandLineArgs args = new SimpleCommandLineArgsParser().parse();
-		assertThatExceptionOfType(UnsupportedOperationException.class).isThrownBy(() ->
+		assertThatExceptionOfType(UnsupportedOperationException.class)
-				args.getOptionNames().add("bogus"));
+				.isThrownBy(() -> args.getOptionNames().add("bogus"));
 	}
 
 	@Test
-	void assertNonOptionArgsIsUnmodifiable() {
+	void nonOptionArgsListIsUnmodifiable() {
 		CommandLineArgs args = new SimpleCommandLineArgsParser().parse();
-		assertThatExceptionOfType(UnsupportedOperationException.class).isThrownBy(() ->
+		assertThatExceptionOfType(UnsupportedOperationException.class)
-				args.getNonOptionArgs().add("foo"));
+				.isThrownBy(() -> args.getNonOptionArgs().add("foo"));
 	}
 
 	@Test

spring-core/src/test/java/org/springframework/core/env/SimpleCommandLinePropertySourceTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -61,6 +61,15 @@ class SimpleCommandLinePropertySourceTests {
 		assertThat(ps.getProperty("o3")).isNull();
 	}
 
+	@Test  // gh-34282
+	void withRepeatedOptionArgs() {
+		CommandLinePropertySource<?> ps = new SimpleCommandLinePropertySource("--o1=v1", "--o1=v2", "--o1=v3");
+		assertThat(ps.containsProperty("o1")).isTrue();
+		assertThat(ps.containsProperty("o2")).isFalse();
+		assertThat(ps.getProperty("o1")).isEqualTo("v1,v2,v3");
+		assertThat(ps.getProperty("o2")).isNull();
+	}
+
 	@Test // gh-24464
 	void withOptionalArg_andArgIsEmpty() {
 		EnumerablePropertySource<?> ps = new SimpleCommandLinePropertySource("--foo=");