HttpClientConnection.getHeaderFields should support multiple values for same header

Bug: 537166
Change-Id: I1ba645968efe01a88f2484f030b7572228ba169c
Signed-off-by: Gabriel Couto <gmcouto@gmail.com>

lib/BUILD

@@ -51,6 +51,7 @@ java_library(
     name = "httpcore",
     visibility = [
         "//org.eclipse.jgit.http.apache:__pkg__",
+        "//org.eclipse.jgit.http.test:__pkg__",
         "//org.eclipse.jgit.lfs.server:__pkg__",
         "//org.eclipse.jgit.lfs.server.test:__pkg__",
         "//org.eclipse.jgit.pgm:__pkg__",

org.eclipse.jgit.http.apache/src/org/eclipse/jgit/transport/http/apache/HttpClientConnection.java

@@ -272,10 +272,14 @@ public class HttpClientConnection implements HttpConnection {
 	public Map<String, List<String>> getHeaderFields() {
 		Map<String, List<String>> ret = new HashMap<>();
 		for (Header hdr : resp.getAllHeaders()) {
-			List<String> list = new LinkedList<>();
-			for (HeaderElement hdrElem : hdr.getElements())
+			List<String> list = ret.get(hdr.getName());
+			if (list == null) {
+				list = new LinkedList<>();
+				ret.put(hdr.getName(), list);
+			}
+			for (HeaderElement hdrElem : hdr.getElements()) {
 				list.add(hdrElem.toString());
-			ret.put(hdr.getName(), list);
+			}
 		}
 		return ret;
 	}

org.eclipse.jgit.http.test/BUILD

@@ -10,6 +10,7 @@ junit_tests(
     deps = [
         ":helpers",
         "//lib:commons-logging",
+        "//lib:httpcore",
         "//lib:jetty-http",
         "//lib:jetty-io",
         "//lib:jetty-security",

org.eclipse.jgit.http.test/META-INF/MANIFEST.MF

@@ -11,6 +11,9 @@ Import-Package: javax.servlet;version="[2.5.0,3.2.0)",
  javax.servlet.http;version="[2.5.0,3.2.0)",
  org.apache.commons.codec;version="[1.6.0,2.0.0)",
  org.apache.commons.codec.binary;version="[1.6.0,2.0.0)",
+ org.apache.http;version="[4.3.0,5.0.0)",
+ org.apache.http.client;version="[4.3.0,5.0.0)",
+ org.apache.http.message;version="[4.3.0,5.0.0)",
  org.eclipse.jetty.continuation;version="[9.4.5,10.0.0)",
  org.eclipse.jetty.http;version="[9.4.5,10.0.0)",
  org.eclipse.jetty.io;version="[9.4.5,10.0.0)",

org.eclipse.jgit.http.test/tst/org/eclipse/jgit/transport/http/apache/HttpClientConnectionTest.java

@@ -0,0 +1,90 @@
+package org.eclipse.jgit.transport.http.apache;
+
+import org.apache.http.HttpEntity;
+import org.apache.http.HttpResponse;
+import org.apache.http.ProtocolVersion;
+import org.apache.http.StatusLine;
+import org.apache.http.message.AbstractHttpMessage;
+import org.junit.Test;
+
+import java.net.MalformedURLException;
+import java.util.List;
+import java.util.Locale;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+public class HttpClientConnectionTest {
+    @Test
+    public void testGetHeaderFieldsAllowMultipleValues() throws MalformedURLException {
+        HttpResponse responseMock = new HttpResponseMock();
+        String headerField = "WWW-Authenticate";
+        responseMock.addHeader(headerField, "Basic");
+        responseMock.addHeader(headerField, "Digest");
+        responseMock.addHeader(headerField, "NTLM");
+        HttpClientConnection connection = new HttpClientConnection("http://0.0.0.0/");
+        connection.resp = responseMock;
+        List<String> headerValues = connection.getHeaderFields().get(headerField);
+        assertEquals(3, headerValues.size());
+        assertTrue(headerValues.contains("Basic"));
+        assertTrue(headerValues.contains("Digest"));
+        assertTrue(headerValues.contains("NTLM"));
+    }
+
+    private class HttpResponseMock extends AbstractHttpMessage implements HttpResponse {
+        @Override
+        public StatusLine getStatusLine() {
+            return null;
+        }
+
+        @Override
+        public void setStatusLine(StatusLine statusLine) {
+
+        }
+
+        @Override
+        public void setStatusLine(ProtocolVersion protocolVersion, int i) {
+
+        }
+
+        @Override
+        public void setStatusLine(ProtocolVersion protocolVersion, int i, String s) {
+
+        }
+
+        @Override
+        public void setStatusCode(int i) throws IllegalStateException {
+
+        }
+
+        @Override
+        public void setReasonPhrase(String s) throws IllegalStateException {
+
+        }
+
+        @Override
+        public HttpEntity getEntity() {
+            return null;
+        }
+
+        @Override
+        public void setEntity(HttpEntity httpEntity) {
+
+        }
+
+        @Override
+        public Locale getLocale() {
+            return null;
+        }
+
+        @Override
+        public void setLocale(Locale locale) {
+
+        }
+
+        @Override
+        public ProtocolVersion getProtocolVersion() {
+            return null;
+        }
+    }
+}