Fix host resolution and concurrent cache updates

internal/ssh/args_regression_test.go

@@ -0,0 +1,46 @@
+package ssh
+
+import "testing"
+
+func TestParseOptionClusters(t *testing.T) {
+	for _, args := range [][]string{
+		{"-vp", "2222", "server"},
+		{"-vp2222", "server"},
+		{"-vAl", "admin", "server"},
+		{"-vladmin", "server"},
+		{"-B", "eth0", "server"},
+		{"-P", "production", "server"},
+	} {
+		t.Run(args[0], func(t *testing.T) {
+			assertParsed(t, Parse(args), "server", "", len(args)-1)
+		})
+	}
+}
+
+func TestExplicitSSHOptions(t *testing.T) {
+	for _, tc := range []struct {
+		name       string
+		args       []string
+		user, port bool
+	}{
+		{"cluster port separated", []string{"-vp", "2222", "server"}, false, true},
+		{"cluster user attached", []string{"-vladmin", "server"}, true, false},
+		{"o separated", []string{"-o", "User=admin", "-o", "Port=2222", "server"}, true, true},
+		{"o attached and case insensitive", []string{"-ouSeR=admin", "-oport=2222", "server"}, true, true},
+		{"o whitespace", []string{"-o", " User = admin", "-o", "Port\t2222", "server"}, true, true},
+		{"cluster o", []string{"-voUser=admin", "server"}, true, false},
+		{"option value looks like flag", []string{"-i", "-lroot", "-F", "-p2222", "server"}, false, false},
+		{"remote flags", []string{"server", "-p2222", "-o", "User=admin"}, false, false},
+		{"after double dash", []string{"--", "-lroot", "-p2222"}, false, false},
+		{"missing value", []string{"-vp"}, false, false},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			if got := HasUserFlag(tc.args); got != tc.user {
+				t.Errorf("HasUserFlag(%v) = %v, want %v", tc.args, got, tc.user)
+			}
+			if got := HasPortFlag(tc.args); got != tc.port {
+				t.Errorf("HasPortFlag(%v) = %v, want %v", tc.args, got, tc.port)
+			}
+		})
+	}
+}