ActiveDirectoryServicePrincipalAccessToken: password/token not propagated to driver

[dlevy-msft-sql]

sqlcmd advertises ActiveDirectoryServicePrincipalAccessToken via --authentication-method (see the help string in cmd/sqlcmd/sqlcmd.go around line 454), but the method does not actually work end-to-end.

Root cause

The go-mssqldb azuread connector for this method expects the pre-obtained bearer token to arrive in the connection string as the password. sqlcmd's pkg/sqlcmd/connect.go only attaches url.UserPassword(UserName, Password) to the URL for a specific set of methods (SqlPassword, ActiveDirectoryPassword, ActiveDirectoryServicePrincipal, ActiveDirectoryApplication, ActiveDirectoryClientAssertion). ActiveDirectoryServicePrincipalAccessToken is not in that list, so the value of -P / SQLCMDPASSWORD is silently dropped and the driver receives no token.

Repro

SQLCMDPASSWORD=<a valid AAD access token> sqlcmd -S <server> --authentication-method ActiveDirectoryServicePrincipalAccessToken -U <ignored>

Driver fails because no token was passed.

Suggested fix

Add ActiveDirectoryServicePrincipalAccessToken (and audit other azuread methods for the same gap) to the password-propagation branch in pkg/sqlcmd/connect.go.

Context

Surfaced in #639 while updating README docs to enumerate the supported --authentication-method values.