Polish "Remove default spring.mongodb.embedded.version"

See gh-27108

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/mongo/embedded/EmbeddedMongoAutoConfiguration.java

@@ -145,7 +145,8 @@ public class EmbeddedMongoAutoConfiguration {
 	}
 
 	private IFeatureAwareVersion determineVersion(EmbeddedMongoProperties embeddedProperties) {
-		Assert.state(embeddedProperties.getVersion() != null, "Version must be set to use Embedded MongoDB.");
+		Assert.state(embeddedProperties.getVersion() != null, "Set the spring.mongodb.embedded.version property or "
+				+ "define your own MongodConfig bean to use embedded MongoDB");
 		if (embeddedProperties.getFeatures() == null) {
 			for (Version version : Version.values()) {
 				if (version.asInDownloadPath().equals(embeddedProperties.getVersion())) {

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/mongo/embedded/EmbeddedMongoAutoConfigurationTests.java

@@ -81,7 +81,8 @@ class EmbeddedMongoAutoConfigurationTests {
 		this.context.register(MongoAutoConfiguration.class, MongoDataAutoConfiguration.class,
 				EmbeddedMongoAutoConfiguration.class);
 		assertThatThrownBy(() -> this.context.refresh()).hasRootCauseExactlyInstanceOf(IllegalStateException.class)
-				.hasRootCauseMessage("Version must be set to use Embedded MongoDB.");
+				.hasRootCauseMessage("Set the spring.mongodb.embedded.version property or define your own MongodConfig "
+						+ "bean to use embedded MongoDB");
 	}
 
 	@Test

spring-boot-project/spring-boot-docs/build.gradle

@@ -220,7 +220,8 @@ tasks.withType(org.asciidoctor.gradle.jvm.AbstractAsciidoctorTask) {
 	}
 	doFirst {
 		def versionConstraints = dependencyVersions.versionConstraints
-		attributes	"jetty-version": versionConstraints["org.eclipse.jetty:jetty-server"],
+		attributes	"embedded-mongo-version": versionConstraints["de.flapdoodle.embed:de.flapdoodle.embed.mongo"],
+					"jetty-version": versionConstraints["org.eclipse.jetty:jetty-server"],
 					"jooq-version": versionConstraints["org.jooq:jooq"],
 					"spring-amqp-version": versionConstraints["org.springframework.amqp:spring-amqp"],
 					"spring-batch-version": versionConstraints["org.springframework.batch:spring-batch-core"],

spring-boot-project/spring-boot-docs/src/docs/asciidoc/attributes.adoc

@@ -93,6 +93,7 @@
 :spring-webservices-docs: https://docs.spring.io/spring-ws/docs/{spring-webservices-version}/reference/html/
 :ant-docs: https://ant.apache.org/manual
 :dependency-management-plugin-code: https://github.com/spring-gradle-plugins/dependency-management-plugin
+:embedded-mongo-code: https://github.com/flapdoodle-oss/de.flapdoodle.embed.mongo/blob/de.flapdoodle.embed.mongo-{embedded-mongo-version}
 :gradle-docs: https://docs.gradle.org/current/userguide
 :hibernate-docs: https://docs.jboss.org/hibernate/orm/5.4/userguide/html_single/Hibernate_User_Guide.html
 :java-api: https://docs.oracle.com/javase/8/docs/api

spring-boot-project/spring-boot-docs/src/docs/asciidoc/data/nosql.adoc

@@ -149,14 +149,11 @@ TIP: For complete details of Spring Data MongoDB, including its rich object mapp
 [[data.nosql.mongodb.embedded]]
 ==== Embedded Mongo
 Spring Boot offers auto-configuration for https://github.com/flapdoodle-oss/de.flapdoodle.embed.mongo[Embedded Mongo].
-To use it in your Spring Boot application, add a dependency on `de.flapdoodle.embed:de.flapdoodle.embed.mongo`.
+To use it in your Spring Boot application, add a dependency on `de.flapdoodle.embed:de.flapdoodle.embed.mongo` and set the configprop:spring.mongodb.embedded.version[] property to match the version of MongoDB that your application will use in production.
 
-The version of the MongoDB server **must** be configured by setting the configprop:spring.data.mongodb.embedded.version property.
-
-NOTE: The default download configuration allows access to most of the versions listed in https://github.com/flapdoodle-oss/de.flapdoodle.embed.mongo/blob/de.flapdoodle.embed.mongo-3.0.0/src/main/java/de/flapdoodle/embed/mongo/distribution/Version.java[Version.java]
-as well as some others. Inaccessible versions result in error when attempting to download the server. The download configuration may be adjusted to handle the desired version.
-
-The download configuration can be customized by declaring a `DownloadConfigBuilderCustomizer` bean.
+NOTE: The default download configuration allows access to most of the versions listed in {embedded-mongo-code}/src/main/java/de/flapdoodle/embed/mongo/distribution/Version.java[Embedded Mongo's `Version` class] as well as some others.
+Configuring an inaccessible version will result in an error when attempting to download the server.
+Such an error can be corrected by defining an appropriately configured `DownloadConfigBuilderCustomizer` bean.
 
 The port that Mongo listens on can be configured by setting the configprop:spring.data.mongodb.port[] property.
 To use a randomly allocated free port, use a value of 0.
@@ -167,6 +164,7 @@ NOTE: If you do not configure a custom port, the embedded support uses a random
 If you have SLF4J on the classpath, the output produced by Mongo is automatically routed to a logger named `org.springframework.boot.autoconfigure.mongo.embedded.EmbeddedMongo`.
 
 You can declare your own `IMongodConfig` and `IRuntimeConfig` beans to take control of the Mongo instance's configuration and logging routing.
+The download configuration can be customized by declaring a `DownloadConfigBuilderCustomizer` bean.
 
 
 [[data.nosql.neo4j]]