fix: we will ask the server if it supports GSS Encryption if gssEncry…

…ption is prefer or require (#2396)

* fix: we will ask the server if it supports GSS Encryption if gssEncryption is prefer or require

* remove the need to have a ticket in the cache before asking the server if gss encryptions are supported

pgjdbc/src/main/java/org/postgresql/core/v3/ConnectionFactoryImpl.java

@@ -31,7 +31,6 @@
 import org.postgresql.sspi.ISSPIClient;
 import org.postgresql.util.GT;
 import org.postgresql.util.HostSpec;
-import org.postgresql.util.KerberosTicket;
 import org.postgresql.util.MD5Digest;
 import org.postgresql.util.PSQLException;
 import org.postgresql.util.PSQLState;
@@ -442,15 +441,16 @@ private PGStream enableGSSEncrypted(PGStream pgStream, GSSEncMode gssEncMode, St
       return pgStream;
     }
 
-    // If there is not credential cache there is little point in attempting this
-    if (!KerberosTicket.credentialCacheExists(info)) {
-      if ( gssEncMode == GSSEncMode.REQUIRE ) {
-        throw new PSQLException("GSSAPI encryption required but was impossible (possibly no credential cache)", PSQLState.CONNECTION_REJECTED);
-      } else {
-        return pgStream;
-      }
-    }
-
+    /*
+     at this point gssEncMode is either PREFER or REQUIRE
+     libpq looks to see if there is a ticket in the cache before asking
+     the server if it supports encrypted GSS connections or not.
+     since the user has specifically asked or either prefer or require we can
+     assume they want it.
+     */
+    /*
+    let's see if the server will allow a GSS encrypted connection
+     */
     String user = PGProperty.USER.get(info);
     if (user == null) {
       throw new PSQLException("GSSAPI encryption required but was impossible user is null", PSQLState.CONNECTION_REJECTED);