Work around bug in Gradle's Eclipse model

The model incorrectly marks the Gradle API and all of its
dependencies as test dependencies, making them unavailable in Eclipse
to code in src/main/java. We work around this by modifying the
classpath container to remove the test attribute from the
dependencies that should be available to main code.

See gh-41228

Author: wilkinsona

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/build.gradle

@@ -1,3 +1,7 @@
+import org.gradle.plugins.ide.eclipse.EclipsePlugin
+import org.gradle.plugins.ide.eclipse.model.Classpath
+import org.gradle.plugins.ide.eclipse.model.Library
+
 plugins {
 	id "java-gradle-plugin"
 	id "maven-publish"
@@ -219,3 +223,19 @@ publishing {
 		}
 	}
 }
+
+plugins.withType(EclipsePlugin) {
+	eclipse {
+		classpath.file { merger ->
+			merger.whenMerged { content ->
+				if (content instanceof Classpath) {
+					content.entries.each { entry ->
+						if (entry instanceof Library && (entry.path.contains("gradle-api-") || entry.path.contains("groovy-"))) {
+							entry.entryAttributes.remove("test")
+						}
+					}
+				}
+			}
+		}
+	}
+}