GH-3271: Close session on error in stream source

Fixes #3271

When exception happens at `.withPayload(session.readRaw(remotePath))`
in the `AbstractRemoteFileStreamingMessageSource` we don't close session.
The resource leaking happens in the caching session factory

* Add `session.close();` into the `catch (IOException e) {`
in the `AbstractRemoteFileStreamingMessageSource.doReceive()`
to clean up resources properly

**Cherry-pick to 5.2.x, 5.1.x & 4.3.x**

Author: artembilan

spring-integration-file/src/main/java/org/springframework/integration/file/remote/AbstractRemoteFileStreamingMessageSource.java

@@ -216,6 +216,7 @@ protected Object doReceive() {
 									this.fileInfoJson ? file.toJson() : file);
 				}
 				catch (IOException e) {
+					session.close();
 					throw new UncheckedIOException("IOException when retrieving " + remotePath, e);
 				}
 			}

spring-integration-file/src/test/java/org/springframework/integration/file/remote/RemoteFileStreamingMessageSourceTests.java

@@ -17,22 +17,26 @@
 package org.springframework.integration.file.remote;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.UncheckedIOException;
 import java.util.Collection;
 import java.util.Comparator;
 import java.util.List;
 import java.util.stream.Collectors;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 import org.springframework.beans.factory.BeanFactory;
 import org.springframework.integration.file.filters.FileListFilter;
+import org.springframework.integration.file.remote.session.CachingSessionFactory;
 import org.springframework.integration.file.remote.session.Session;
+import org.springframework.integration.file.remote.session.SessionFactory;
 
 /**
  * @author Lukas Gemela
@@ -69,6 +73,32 @@ public void filterOutFilesNotAcceptedByFilter() throws IOException {
 		assertThat(testRemoteFileStreamingMessageSource.doReceive()).isNull();
 	}
 
+	@Test
+	@SuppressWarnings("unchecked")
+	public void sessionReturnedToCacheProperlyOnDoReceive() throws IOException {
+		Session<String> session = mock(Session.class);
+		when(session.readRaw(anyString())).thenThrow(IOException.class);
+		when(session.list("remoteDirectory")).thenReturn(new String[] { "file1" });
+
+		SessionFactory<String> sessionFactory = mock(SessionFactory.class);
+		when(sessionFactory.getSession()).thenReturn(session);
+
+		CachingSessionFactory<String> cachingSessionFactory = new CachingSessionFactory<>(sessionFactory, 1);
+		RemoteFileTemplate<String> remoteFileTemplate = new RemoteFileTemplate<>(cachingSessionFactory);
+
+		TestRemoteFileStreamingMessageSource testRemoteFileStreamingMessageSource =
+				new TestRemoteFileStreamingMessageSource(remoteFileTemplate, null);
+
+		testRemoteFileStreamingMessageSource.setRemoteDirectory("remoteDirectory");
+		testRemoteFileStreamingMessageSource.setBeanFactory(mock(BeanFactory.class));
+		testRemoteFileStreamingMessageSource.start();
+
+		assertThatExceptionOfType(UncheckedIOException.class)
+				.isThrownBy(testRemoteFileStreamingMessageSource::doReceive);
+
+		assertThat(cachingSessionFactory.getSession()).isNotNull();
+	}
+
 	static class TestRemoteFileStreamingMessageSource extends AbstractRemoteFileStreamingMessageSource<String> {
 
 		TestRemoteFileStreamingMessageSource(RemoteFileTemplate<String> template, Comparator<String> comparator) {