ProtocolV2Parser: Introduce advertise sideband-all option

The flag enabling sideband-all is used in two places: in UploadPack
for advertisement and in the protocol parser to read it from the
request.

This leds to problems in distributed deployments where the two requests of
a fetch can go to different servers with different configurations.

Use the existing allowsidebandall to accept the sideband-all request
(and respond to it) and introduce a new "advertisesidebandall" to toggle
the advertising of the feature.

Change-Id: I892d541bc3f321606c89bad1d333b079dce6b5fa
Signed-off-by: Ivan Frade <ifrade@google.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/UploadPackTest.java

@@ -501,8 +501,11 @@ public void testV2CapabilitiesRefInWantNotAdvertisedIfUnallowed() throws Excepti
 	}
 
 	@Test
-	public void testV2CapabilitiesAllowSidebandAll() throws Exception {
-		checkAdvertisedIfAllowed("uploadpack", "allowsidebandall", "sideband-all");
+	public void testV2CapabilitiesAdvertiseSidebandAll() throws Exception {
+		server.getConfig().setBoolean("uploadpack", null, "allowsidebandall",
+				true);
+		checkAdvertisedIfAllowed("uploadpack", "advertisesidebandall",
+				"sideband-all");
 		checkUnadvertisedIfUnallowed("sideband-all");
 	}
 

org.eclipse.jgit/src/org/eclipse/jgit/transport/TransferConfig.java

@@ -132,6 +132,7 @@ static ProtocolVersion parse(@Nullable String name) {
 	private final boolean allowReachableSha1InWant;
 	private final boolean allowFilter;
 	private final boolean allowSidebandAll;
+	private final boolean advertiseSidebandAll;
 	final @Nullable ProtocolVersion protocolVersion;
 	final String[] hideRefs;
 
@@ -213,6 +214,8 @@ public TransferConfig(Config rc) {
 		hideRefs = rc.getStringList("uploadpack", null, "hiderefs");
 		allowSidebandAll = rc.getBoolean(
 				"uploadpack", "allowsidebandall", false);
+		advertiseSidebandAll = rc.getBoolean("uploadpack",
+				"advertisesidebandall", false);
 	}
 
 	/**
@@ -295,13 +298,22 @@ public boolean isAllowRefInWant() {
 	}
 
 	/**
-	 * @return true if clients are allowed to specify a "sideband-all" line
+	 * @return true if the server accepts sideband-all requests (see
+	 *         {{@link #isAdvertiseSidebandAll()} for the advertisement)
 	 * @since 5.5
 	 */
 	public boolean isAllowSidebandAll() {
 		return allowSidebandAll;
 	}
 
+	/**
+	 * @return true to advertise sideband all to the clients
+	 * @since 5.6
+	 */
+	public boolean isAdvertiseSidebandAll() {
+		return advertiseSidebandAll && allowSidebandAll;
+	}
+
 	/**
 	 * Get {@link org.eclipse.jgit.transport.RefFilter} respecting configured
 	 * hidden refs.

org.eclipse.jgit/src/org/eclipse/jgit/transport/UploadPack.java

@@ -1325,7 +1325,7 @@ private List<String> getV2CapabilityAdvertisement() {
 		caps.add(COMMAND_FETCH + '='
 				+ (transferConfig.isAllowFilter() ? OPTION_FILTER + ' ' : "")
 				+ (advertiseRefInWant ? CAPABILITY_REF_IN_WANT + ' ' : "")
-				+ (transferConfig.isAllowSidebandAll()
+				+ (transferConfig.isAdvertiseSidebandAll()
 						? OPTION_SIDEBAND_ALL + ' '
 						: "")
 				+ (cachedPackUriProvider != null ? "packfile-uris " : "")