Auth switch special case one host with two users to avoid unnecessary prompting

pkg/cmd/auth/switch/switch.go

@@ -68,16 +68,6 @@ type hostUser struct {
 
 type candidates []hostUser
 
-func (c candidates) inactiveOptions() []hostUser {
-	var inactive []hostUser
-	for _, candidate := range c {
-		if !candidate.active {
-			inactive = append(inactive, candidate)
-		}
-	}
-	return inactive
-}
-
 func switchRun(opts *SwitchOptions) error {
 	hostname := opts.Hostname
 	username := opts.Username
@@ -125,15 +115,20 @@ func switchRun(opts *SwitchOptions) error {
 		}
 	}
 
-	inactiveCandidates := candidates.inactiveOptions()
 	if len(candidates) == 0 {
 		return errors.New("no accounts matched that criteria")
 	} else if len(candidates) == 1 {
 		hostname = candidates[0].host
 		username = candidates[0].user
-	} else if len(inactiveCandidates) == 1 {
-		hostname = inactiveCandidates[0].host
-		username = inactiveCandidates[0].user
+	} else if len(candidates) == 2 &&
+		candidates[0].host == candidates[1].host {
+		// If there is a single host with two users, automatically swith to the
+		// inactive user without prompting.
+		hostname = candidates[0].host
+		username = candidates[0].user
+		if candidates[0].active {
+			username = candidates[1].user
+		}
 	} else if !opts.IO.CanPrompt() {
 		return errors.New("unable to determine which account to switch to, please specify `--hostname` and `--user`")
 	} else {

pkg/cmd/auth/switch/switch_test.go

@@ -320,6 +320,38 @@ func TestSwitchRun(t *testing.T) {
 				stderr:       "✓ Switched active account for ghe.io to inactive-user",
 			},
 		},
+		{
+			name: "options need to be disambiguated given two hosts, one with two users",
+			opts: SwitchOptions{},
+			cfgHosts: []hostUsers{
+				{"github.com", []user{
+					{"inactive-user", "inactive-user-token"},
+					{"active-user", "active-user-token"},
+				}},
+				{"ghe.io", []user{
+					{"active-user", "active-user-token"},
+				}},
+			},
+			prompterStubs: func(pm *prompter.PrompterMock) {
+				pm.SelectFunc = func(prompt, _ string, opts []string) (int, error) {
+					require.Equal(t, "What account do you want to switch to?", prompt)
+					require.Equal(t, []string{
+						"inactive-user (github.com)",
+						"active-user (github.com) - active",
+						"active-user (ghe.io) - active",
+					}, opts)
+
+					return prompter.IndexFor(opts, "inactive-user (github.com)")
+				}
+			},
+			expectedSuccess: successfulExpectation{
+				switchedHost: "github.com",
+				activeUser:   "inactive-user",
+				activeToken:  "inactive-user-token",
+				hostsCfg:     "github.com:\n    git_protocol: ssh\n    users:\n        inactive-user:\n        active-user:\n    user: inactive-user\nghe.io:\n    git_protocol: ssh\n    users:\n        active-user:\n    user: active-user\n",
+				stderr:       "✓ Switched active account for github.com to inactive-user",
+			},
+		},
 		{
 			name: "when switching fails due to something other than user error, an informative message is printed to explain their new state",
 			opts: SwitchOptions{
@@ -351,6 +383,9 @@ func TestSwitchRun(t *testing.T) {
 				pm := &prompter.PrompterMock{}
 				tt.prompterStubs(pm)
 				tt.opts.Prompter = pm
+				defer func() {
+					require.Len(t, pm.SelectCalls(), 1)
+				}()
 			}
 
 			for _, hostUsers := range tt.cfgHosts {