api: auth: fix nil deref

By pulling in the fixes from c/common.  Add regression tests to make
sure it's not happening another time.  The error messages are not
ideal and should probably be optimized in the `/auth` endpoints directly
but it's already an improvement over a nil deref.

Signed-off-by: Valentin Rothberg <vrothberg@redhat.com>

vendor/github.com/containers/common/pkg/auth/auth.go

@@ -242,14 +242,19 @@ func replaceURLByHostPort(repository string) (string, error) {
 // using the -u and -p flags.  If the username prompt is left empty, the
 // displayed userFromAuthFile will be used instead.
 func getUserAndPass(opts *LoginOptions, password, userFromAuthFile string) (user, pass string, err error) {
-	reader := bufio.NewReader(opts.Stdin)
 	username := opts.Username
 	if username == "" {
+		if opts.Stdin == nil {
+			return "", "", fmt.Errorf("cannot prompt for username without stdin")
+		}
+
 		if userFromAuthFile != "" {
 			fmt.Fprintf(opts.Stdout, "Username (%s): ", userFromAuthFile)
 		} else {
 			fmt.Fprint(opts.Stdout, "Username: ")
 		}
+
+		reader := bufio.NewReader(opts.Stdin)
 		username, err = reader.ReadString('\n')
 		if err != nil {
 			return "", "", fmt.Errorf("reading username: %w", err)

vendor/github.com/containers/common/version/version.go

@@ -1,4 +1,4 @@
 package version
 
 // Version is the version of the build.
-const Version = "0.52.0"
+const Version = "0.53.0-dev"