Add warnings for errors while parsing a SnowflakeConnectString (#1166)

code changes is only for log entries. Test failures expected from external fork. No need to run it as such for this PR.

src/main/java/net/snowflake/client/jdbc/SnowflakeConnectString.java

@@ -31,10 +31,12 @@ public class SnowflakeConnectString implements Serializable {
 
   public static SnowflakeConnectString parse(String url, Properties info) {
     if (url == null) {
+      logger.warn("Connect strings must be non-null");
       return INVALID_CONNECT_STRING;
     }
     int pos = url.indexOf(PREFIX);
     if (pos != 0) {
+      logger.warn("Connect strings must start with jdbc:snowflake://");
       return INVALID_CONNECT_STRING; // not start with jdbc:snowflake://
     }
     String afterPrefix = url.substring(pos + PREFIX.length());
@@ -62,16 +64,19 @@ public static SnowflakeConnectString parse(String url, Properties info) {
       String queryData = uri.getRawQuery();
 
       if (!scheme.equals("snowflake") && !scheme.equals("http") && !scheme.equals("https")) {
+        logger.warn("Connect strings must have a valid scheme: 'snowflake' or 'http' or 'https'");
         return INVALID_CONNECT_STRING;
       }
       if (Strings.isNullOrEmpty(host)) {
+        logger.warn("Connect strings must have a valid host: found null or empty host");
         return INVALID_CONNECT_STRING;
       }
       if (port == -1) {
         port = 443;
       }
       String path = uri.getPath();
       if (!Strings.isNullOrEmpty(path) && !"/".equals(path)) {
+        logger.warn("Connect strings must have no path: expecting empty or null or '/'");
         return INVALID_CONNECT_STRING;
       }
       String account = null;
@@ -147,6 +152,7 @@ public static SnowflakeConnectString parse(String url, Properties info) {
 
       return new SnowflakeConnectString(scheme, host, port, parameters, account);
     } catch (Exception ex) {
+      logger.warn("Exception thrown while parsing Snowflake connect string", ex);
       return INVALID_CONNECT_STRING;
     }
   }