Description:
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When creating a PDO object using the pgsql driver, the supplied username is dropped if the password is null.



Reproduce code:
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$pdo = new PDO('pgsql:host=localhost;port=5777;dbname=mydb', 'myuser');


This will not use the "myuser" username supplied.  Looking at the code in ext/pdo_pgsql/pgsql_driver.c circa line 695 it says:

        /* support both full connection string & connection string + login and/or password */
        if (!dbh->username || !dbh->password) {
                spprintf(&conn_str, 0, "%s connect_timeout=%ld", (char *) dbh->data_source, connect_timeout);
        } else if (dbh->username && dbh->password) {
                spprintf(&conn_str, 0, "%s user=%s password=%s connect_timeout=%ld", dbh->data_source, dbh->username, dbh->password, connect_timeout);
        } else if (dbh->username) {
                spprintf(&conn_str, 0, "%s user=%s connect_timeout=%ld", dbh->data_source, dbh->username, connect_timeout);
        } else {
                spprintf(&conn_str, 0, "%s password=%s connect_timeout=%ld", dbh->data_source, dbh->password, connect_timeout);
        }

It's trying to cover all the cases of username and password set or not, but the first condition is wrong.  It should be 

        if (!dbh->username && !dbh->password) {