Map non-null LDAP properties

The userDn and password in LdapContextSource are not nullable. The
default values for userDn and password in LdapProperties are null. When
the values are set to null there will eventually be a
NullPointerException during
AbstractContextSource#setupAuthenticatedEnvironment since HashTable
doesn't allow null for values.

See gh-17861

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/ldap/LdapAutoConfiguration.java

@@ -22,6 +22,7 @@ import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.boot.context.properties.PropertyMapper;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.env.Environment;
@@ -55,12 +56,14 @@ public class LdapAutoConfiguration {
 	@ConditionalOnMissingBean
 	public LdapContextSource ldapContextSource() {
 		LdapContextSource source = new LdapContextSource();
-		source.setUserDn(this.properties.getUsername());
-		source.setPassword(this.properties.getPassword());
-		source.setAnonymousReadOnly(this.properties.getAnonymousReadOnly());
-		source.setBase(this.properties.getBase());
-		source.setUrls(this.properties.determineUrls(this.environment));
-		source.setBaseEnvironmentProperties(Collections.unmodifiableMap(this.properties.getBaseEnvironment()));
+		PropertyMapper propertyMapper = PropertyMapper.get().alwaysApplyingWhenNonNull();
+		propertyMapper.from(this.properties.getUsername()).to(source::setUserDn);
+		propertyMapper.from(this.properties.getPassword()).to(source::setPassword);
+		propertyMapper.from(this.properties.getAnonymousReadOnly()).to(source::setAnonymousReadOnly);
+		propertyMapper.from(this.properties.getBase()).to(source::setBase);
+		propertyMapper.from(this.properties.determineUrls(this.environment)).to(source::setUrls);
+		propertyMapper.from(this.properties.getBaseEnvironment()).to(
+				(baseEnvironment) -> source.setBaseEnvironmentProperties(Collections.unmodifiableMap(baseEnvironment)));
 		return source;
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/ldap/LdapAutoConfigurationTests.java

@@ -90,6 +90,17 @@ public class LdapAutoConfigurationTests {
 				});
 	}
 
+	@Test
+	public void contextSourceWithNoCustomization() {
+		this.contextRunner.run((context) -> {
+			LdapContextSource contextSource = context.getBean(LdapContextSource.class);
+			assertThat(contextSource.getUserDn()).isEqualTo("");
+			assertThat(contextSource.getPassword()).isEqualTo("");
+			assertThat(contextSource.isAnonymousReadOnly()).isFalse();
+			assertThat(contextSource.getBaseLdapPathAsString()).isEqualTo("");
+		});
+	}
+
 	@Test
 	public void templateExists() {
 		this.contextRunner.withPropertyValues("spring.ldap.urls:ldap://localhost:389")