Return empty array if ConfigurationPropertySource.from returns null

Fixes gh-1062

spring-cloud-commons/src/main/java/org/springframework/cloud/commons/ConfigDataMissingEnvironmentPostProcessor.java

@@ -53,6 +53,8 @@ public abstract class ConfigDataMissingEnvironmentPostProcessor implements Envir
 
 	private static final Bindable<String[]> CONFIG_DATA_LOCATION_ARRAY = Bindable.of(String[].class);
 
+	private static final String[] EMPTY_ARRAY = new String[0];
+
 	/**
 	 * Order of post processor, set to run after
 	 * {@link ConfigDataEnvironmentPostProcessor}.
@@ -110,15 +112,19 @@ public abstract class ConfigDataMissingEnvironmentPostProcessor implements Envir
 	}
 
 	private String[] getConfigImportArray(PropertySource propertySource) {
-		Binder binder = new Binder(ConfigurationPropertySource.from(propertySource));
+		ConfigurationPropertySource configurationPropertySource = ConfigurationPropertySource.from(propertySource);
+		if (configurationPropertySource == null) {
+			return EMPTY_ARRAY;
+		}
+		Binder binder = new Binder(configurationPropertySource);
 		return binder.bind(CONFIG_IMPORT_PROPERTY, CONFIG_DATA_LOCATION_ARRAY, new BindHandler() {
 			@Override
 			public Object onFailure(ConfigurationPropertyName name, Bindable<?> target, BindContext context,
 					Exception error) throws Exception {
 				LOG.info("Error binding " + CONFIG_IMPORT_PROPERTY, error);
-				return new String[0];
+				return EMPTY_ARRAY;
 			}
-		}).orElse(new String[0]);
+		}).orElse(EMPTY_ARRAY);
 	}
 
 	public static class ImportException extends RuntimeException {

spring-cloud-commons/src/test/java/org/springframework/cloud/commons/ConfigDataMissingEnvironmentPostProcessorTests.java

@@ -17,13 +17,18 @@
 package org.springframework.cloud.commons;
 
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
 
 import org.springframework.boot.SpringApplication;
+import org.springframework.boot.context.properties.source.ConfigurationPropertySources;
+import org.springframework.boot.test.system.CapturedOutput;
+import org.springframework.boot.test.system.OutputCaptureExtension;
 import org.springframework.core.env.CompositePropertySource;
 import org.springframework.core.env.Environment;
 import org.springframework.mock.env.MockEnvironment;
 import org.springframework.mock.env.MockPropertySource;
 
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatCode;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.mockito.Mockito.mock;
@@ -31,6 +36,7 @@ import static org.mockito.Mockito.mock;
 /**
  * @author Ryan Baxter
  */
+@ExtendWith(OutputCaptureExtension.class)
 public class ConfigDataMissingEnvironmentPostProcessorTests {
 
 	@Test
@@ -92,6 +98,18 @@ public class ConfigDataMissingEnvironmentPostProcessorTests {
 		assertThatCode(() -> processor.postProcessEnvironment(environment, app)).doesNotThrowAnyException();
 	}
 
+	@Test
+	void importHandlesNullConfigurationPropertySource(CapturedOutput output) {
+		MockEnvironment environment = new MockEnvironment();
+		ConfigurationPropertySources.attach(environment);
+		environment.setProperty("spring.config.import[0]", "configserver:http://localhost:8888");
+		environment.setProperty("spring.config.import[1]", "file:./app.properties");
+		SpringApplication app = mock(SpringApplication.class);
+		TestConfigDataMissingEnvironmentPostProcessor processor = new TestConfigDataMissingEnvironmentPostProcessor();
+		assertThatCode(() -> processor.postProcessEnvironment(environment, app)).doesNotThrowAnyException();
+		assertThat(output).doesNotContain("Error binding spring.config.import");
+	}
+
 	public class TestConfigDataMissingEnvironmentPostProcessor extends ConfigDataMissingEnvironmentPostProcessor {
 
 		@Override