Fix return error value when login fails

[grethy]

At login failure the returned error is always nil and this creates a connection at sql.Open that is in an invalid state instead of reporting the sybase error that happened during the connection.

After the fix it returns the correct error value and the sql.Open call properly reports the error message

[thda]

Thanks, looks good to me. Merged. Cheers.

[thda]

Needs a test case. If you have time to do it prs are welcome. Otherwise I will do it

[grethy]

Ups, so after some more testing i realized that my description was wrong and it still does not die on the sql.Open (as it should be, since sql.Open does not actually create a connection, i was just not thinking), however the db.Ping() will now report the correct error instead of the old message that comes from the database/sql module when it does not know whats wrong.

Old:
Ping error: driver: bad connection

New:
Ping error: Msg: 4002, Level: 14, State: 1
Server: MYSERVER, Line: 0:
Login failed.

and that helps diagnose login issues. Like in my case the server charset was iso_1 and the default utf-8 setting did not work, but the server errorlog only contained a line about a failed login attempt.

As it is, the TestBadConnect test in driver_test.go captures this and was capturing the previous one too, since its only checking if err contains any message or not. Shall I change it so that it checks that the first line starts with "Msg: 4002" ?

[thda]

Hi,

yes, if you can search for "Login failed" it would be great!

Thanks
Thomas

[thda]

By the way using SetErrorhandler as mentionned in the readme will allow you to print all the error messages.
You should have another message than "Login failed" sent by the server right before, and a more explanatory one.