Prevent resource hint registration for pattern with leading slash

Prior to this commit, if a ResourcePatternHint was created with a
resource pattern with a leading slash, the hint was registered and
eventually converted to configuration for the GraalVM native image
compiler.

However, such a resource pattern is invalid for GraalVM. Consequently,
the registered resources were not available within the compiled native
image.

This commit ensures that registered patterns are applicable in a native
image by preventing creation of a ResourcePatternHint with a pattern
with a leading slash.

Closes gh-29088

spring-core/src/main/java/org/springframework/aot/hint/ResourcePatternHint.java

@@ -22,13 +22,14 @@
 import java.util.stream.Collectors;
 
 import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
 
 /**
  * A hint that describes resources that should be made available at runtime.
  *
- * <p>The patterns may be a simple path which has a one-to-one mapping to a
+ * <p>Each pattern may be a simple path which has a one-to-one mapping to a
  * resource on the classpath, or alternatively may contain the special
- * {@code *} character to indicate a wildcard search. For example:
+ * {@code *} character to indicate a wildcard match. For example:
  * <ul>
  *     <li>{@code file.properties}: matches just the {@code file.properties}
  *         file at the root of the classpath.</li>
@@ -42,9 +43,12 @@
  *         and its child directories at any depth.</li>
  * </ul>
  *
+ * <p>A resource pattern must not start with a slash ({@code /}).
+ *
  * @author Stephane Nicoll
  * @author Brian Clozel
  * @author Sebastien Deleuze
+ * @author Sam Brannen
  * @since 6.0
  */
 public final class ResourcePatternHint implements ConditionalHint {
@@ -55,6 +59,8 @@ public final class ResourcePatternHint implements ConditionalHint {
 	private final TypeReference reachableType;
 
 	ResourcePatternHint(String pattern, @Nullable TypeReference reachableType) {
+		Assert.isTrue(!pattern.startsWith("/"),
+				() -> "Resource pattern [%s] must not start with a '/'".formatted(pattern));
 		this.pattern = pattern;
 		this.reachableType = reachableType;
 	}
@@ -104,4 +110,5 @@ public boolean equals(Object o) {
 	public int hashCode() {
 		return Objects.hash(this.pattern, this.reachableType);
 	}
+
 }

spring-core/src/test/java/org/springframework/aot/hint/ResourcePatternHintTests.java

@@ -19,13 +19,22 @@
 import org.junit.jupiter.api.Test;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
 
 /**
  * Tests for {@link ResourcePatternHint}.
  *
  * @author Sebastien Deleuze
+ * @author Sam Brannen
  */
-public class ResourcePatternHintTests {
+class ResourcePatternHintTests {
+
+	@Test
+	void patternWithLeadingSlashIsRejected() {
+		assertThatIllegalArgumentException()
+				.isThrownBy(() -> new ResourcePatternHint("/file.properties", null))
+				.withMessage("Resource pattern [/file.properties] must not start with a '/'");
+	}
 
 	@Test
 	void fileAtRoot() {
@@ -66,4 +75,5 @@ void anyFileInDirectoryAtAnyDepth() {
 				.accepts("com/example/file.properties", "com/example/another/file.properties", "com/example/another")
 				.rejects("file.properties", "com/file.properties");
 	}
+
 }