Remove Generic Typing From Authentication.Builder

It would be better to introduce parameter types for
principal and credentials into Authentication.Builder
at the same time as doing so for Authentication

Issue gh-17861

core/src/main/java/org/springframework/security/authentication/AbstractAuthenticationToken.java

@@ -69,7 +69,7 @@ public abstract class AbstractAuthenticationToken implements Authentication, Cre
 		this.authorities = Collections.unmodifiableList(new ArrayList<>(authorities));
 	}
 
-	protected AbstractAuthenticationToken(AbstractAuthenticationBuilder<?, ?, ?> builder) {
+	protected AbstractAuthenticationToken(AbstractAuthenticationBuilder<?> builder) {
 		this(builder.authorities);
 		this.authenticated = builder.authenticated;
 		this.details = builder.details;
@@ -197,8 +197,8 @@ public abstract class AbstractAuthenticationToken implements Authentication, Cre
 		return sb.toString();
 	}
 
-	protected abstract static class AbstractAuthenticationBuilder<P, C, B extends AbstractAuthenticationBuilder<P, C, B>>
-			implements Authentication.Builder<P, C, B> {
+	protected abstract static class AbstractAuthenticationBuilder<B extends AbstractAuthenticationBuilder<B>>
+			implements Authentication.Builder<B> {
 
 		protected boolean authenticated;
 

core/src/main/java/org/springframework/security/authentication/RememberMeAuthenticationToken.java

@@ -126,7 +126,7 @@ public class RememberMeAuthenticationToken extends AbstractAuthenticationToken {
 	 *
 	 * @since 7.0
 	 */
-	public static class Builder<B extends Builder<B>> extends AbstractAuthenticationBuilder<Object, Object, B> {
+	public static class Builder<B extends Builder<B>> extends AbstractAuthenticationBuilder<B> {
 
 		private Integer keyHash;
 

core/src/main/java/org/springframework/security/authentication/TestingAuthenticationToken.java

@@ -91,7 +91,7 @@ public class TestingAuthenticationToken extends AbstractAuthenticationToken {
 	 *
 	 * @since 7.0
 	 */
-	public static class Builder<B extends Builder<B>> extends AbstractAuthenticationBuilder<Object, Object, B> {
+	public static class Builder<B extends Builder<B>> extends AbstractAuthenticationBuilder<B> {
 
 		private Object principal;
 

core/src/main/java/org/springframework/security/authentication/UsernamePasswordAuthenticationToken.java

@@ -141,7 +141,7 @@ public class UsernamePasswordAuthenticationToken extends AbstractAuthenticationT
 	 *
 	 * @since 7.0
 	 */
-	public static class Builder<B extends Builder<B>> extends AbstractAuthenticationBuilder<Object, Object, B> {
+	public static class Builder<B extends Builder<B>> extends AbstractAuthenticationBuilder<B> {
 
 		protected @Nullable Object principal;
 

core/src/main/java/org/springframework/security/authentication/ott/OneTimeTokenAuthentication.java

@@ -67,7 +67,7 @@ public class OneTimeTokenAuthentication extends AbstractAuthenticationToken {
 	/**
 	 * A builder for constructing a {@link OneTimeTokenAuthentication} instance
 	 */
-	public static class Builder<B extends Builder<B>> extends AbstractAuthenticationBuilder<Object, Object, B> {
+	public static class Builder<B extends Builder<B>> extends AbstractAuthenticationBuilder<B> {
 
 		private Object principal;
 

core/src/main/java/org/springframework/security/core/Authentication.java

@@ -143,7 +143,7 @@ public interface Authentication extends Principal, Serializable {
 	 * instance
 	 * @since 7.0
 	 */
-	default Builder<?, ?, ?> toBuilder() {
+	default Builder<?> toBuilder() {
 		return new SimpleAuthentication.Builder(this);
 	}
 
@@ -153,18 +153,18 @@ public interface Authentication extends Principal, Serializable {
 	 * @author Josh Cummings
 	 * @since 7.0
 	 */
-	interface Builder<P, C, B extends Builder<P, C, B>> {
+	interface Builder<B extends Builder<B>> {
 
 		B authorities(Consumer<Collection<GrantedAuthority>> authorities);
 
-		default B credentials(@Nullable C credentials) {
+		default B credentials(@Nullable Object credentials) {
 			throw new UnsupportedOperationException(
 					String.format("%s does not store credentials", this.getClass().getSimpleName()));
 		}
 
 		B details(@Nullable Object details);
 
-		B principal(@Nullable P principal);
+		B principal(@Nullable Object principal);
 
 		B authenticated(boolean authenticated);
 

core/src/main/java/org/springframework/security/core/SimpleAuthentication.java

@@ -21,6 +21,8 @@ import java.util.Collection;
 import java.util.LinkedHashSet;
 import java.util.function.Consumer;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.jspecify.annotations.Nullable;
 
 @Transient
@@ -83,7 +85,9 @@ final class SimpleAuthentication implements Authentication {
 		return (this.principal == null) ? "" : this.principal.toString();
 	}
 
-	static final class Builder implements Authentication.Builder<Object, Object, Builder> {
+	static final class Builder implements Authentication.Builder<Builder> {
+
+		private final Log logger = LogFactory.getLog(getClass());
 
 		private final Collection<GrantedAuthority> authorities = new LinkedHashSet<>();
 
@@ -96,11 +100,15 @@ final class SimpleAuthentication implements Authentication {
 		private boolean authenticated;
 
 		Builder(Authentication authentication) {
+			this.logger.debug("Creating a builder which will result in exchanging an authentication of type "
+					+ authentication.getClass() + " for " + SimpleAuthentication.class.getSimpleName() + ";"
+					+ " consider implementing " + authentication.getClass().getSimpleName() + "#toBuilder");
 			this.authorities.addAll(authentication.getAuthorities());
 			this.principal = authentication.getPrincipal();
 			this.credentials = authentication.getCredentials();
 			this.details = authentication.getDetails();
 			this.authenticated = authentication.isAuthenticated();
+
 		}
 
 		@Override

core/src/test/java/org/springframework/security/authentication/AbstractAuthenticationBuilderTests.java

@@ -40,7 +40,7 @@ class AbstractAuthenticationBuilderTests {
 	}
 
 	private static final class TestAbstractAuthenticationBuilder
-			extends AbstractAuthenticationBuilder<Object, Object, TestAbstractAuthenticationBuilder> {
+			extends AbstractAuthenticationBuilder<TestAbstractAuthenticationBuilder> {
 
 		private TestAbstractAuthenticationBuilder(TestingAuthenticationToken token) {
 			super(token);