Fix CLI TTY dependency issues for CI/script usage

- Fix SpinWhile logic to properly handle non-TTY environments
- Add TTY detection to Confirm and PromptForOne functions
- Replace all spinner.New() calls with TTY-aware SpinWhile() calls
- Add non-TTY fallback for agent stop command using direct API calls
- Add comprehensive test coverage for TTY/non-TTY behavior
- All spinner operations now gracefully degrade when no TTY is available

Fixes #496

Amp-Thread: https://ampcode.com/threads/T-04774b89-5ae4-4839-830d-67c16e65acb6
Co-authored-by: Amp <[email protected]>

Author: sj26

internal/agent/stoppable.go

@@ -109,3 +109,11 @@ func (agent StoppableAgent) View() string {
 func (agent StoppableAgent) Errored() bool {
 	return agent.err != nil
 }
+
+func (agent StoppableAgent) Error() error {
+	return agent.err
+}
+
+func (agent StoppableAgent) ID() string {
+	return agent.id
+}

internal/io/confirm.go

@@ -1,10 +1,24 @@
 package io
 
 import (
+	"os"
+
 	"github.com/charmbracelet/huh"
+	"github.com/mattn/go-isatty"
 )
 
 func Confirm(confirmed *bool, title string) error {
+	// If already confirmed via flag, skip the prompt
+	if *confirmed {
+		return nil
+	}
+
+	// If no TTY is available, default to confirmed=true (non-interactive mode)
+	if !isatty.IsTerminal(os.Stdout.Fd()) {
+		*confirmed = true
+		return nil
+	}
+
 	form := huh.NewForm(
 		huh.NewGroup(
 			huh.NewConfirm().

internal/io/confirm_test.go

@@ -0,0 +1,33 @@
+package io
+
+import (
+	"testing"
+)
+
+func TestConfirmWithoutTTY(t *testing.T) {
+	// Test that Confirm works without TTY and defaults to true
+	confirmed := false
+	err := Confirm(&confirmed, "Test confirmation")
+
+	if err != nil {
+		t.Errorf("Confirm should not return error: %v", err)
+	}
+
+	if !confirmed {
+		t.Error("Confirm should default to true when no TTY is available")
+	}
+}
+
+func TestConfirmWithFlag(t *testing.T) {
+	// Test that Confirm respects pre-set flag
+	confirmed := true
+	err := Confirm(&confirmed, "Test confirmation")
+
+	if err != nil {
+		t.Errorf("Confirm should not return error: %v", err)
+	}
+
+	if !confirmed {
+		t.Error("Confirm should respect pre-set flag")
+	}
+}

internal/io/prompt.go

@@ -1,6 +1,12 @@
 package io
 
-import "github.com/charmbracelet/huh"
+import (
+	"errors"
+	"os"
+
+	"github.com/charmbracelet/huh"
+	"github.com/mattn/go-isatty"
+)
 
 const (
 	typeOrganizationMessage = "Pick an organization"
@@ -10,6 +16,11 @@ const (
 // PromptForOne will show the list of options to the user, allowing them to select one to return.
 // It's possible for them to choose none or cancel the selection, resulting in an error.
 func PromptForOne(resource string, options []string) (string, error) {
+	// If no TTY is available, cannot prompt user for selection
+	if !isatty.IsTerminal(os.Stdout.Fd()) {
+		return "", errors.New("cannot prompt for selection: no TTY available (use appropriate flags to specify the selection)")
+	}
+
 	var message string
 	switch resource {
 	case "pipeline":

internal/io/prompt_test.go

@@ -0,0 +1,19 @@
+package io
+
+import (
+	"testing"
+)
+
+func TestPromptForOneWithoutTTY(t *testing.T) {
+	// Test that PromptForOne fails gracefully without TTY
+	_, err := PromptForOne("pipeline", []string{"option1", "option2"})
+
+	if err == nil {
+		t.Error("PromptForOne should return error when no TTY is available")
+	}
+
+	expectedError := "cannot prompt for selection: no TTY available (use appropriate flags to specify the selection)"
+	if err.Error() != expectedError {
+		t.Errorf("Expected error message %q, got %q", expectedError, err.Error())
+	}
+}

internal/io/spinner.go

@@ -8,12 +8,13 @@ import (
 )
 
 func SpinWhile(name string, action func()) error {
-	if isatty.IsTerminal(os.Stdout.Fd()) {
+	if !isatty.IsTerminal(os.Stdout.Fd()) {
+		// No TTY available, just run the action without spinner
 		action()
-
 		return nil
 	}
 
+	// TTY is available, use the spinner
 	return spinner.New().
 		Title(name).
 		Action(action).

internal/io/spinner_test.go

@@ -0,0 +1,21 @@
+package io
+
+import (
+	"testing"
+)
+
+func TestSpinWhileWithoutTTY(t *testing.T) {
+	// Test that SpinWhile works without TTY
+	actionCalled := false
+	err := SpinWhile("Test action", func() {
+		actionCalled = true
+	})
+
+	if err != nil {
+		t.Errorf("SpinWhile should not return error: %v", err)
+	}
+
+	if !actionCalled {
+		t.Error("Action should have been called")
+	}
+}

internal/pipeline/resolver/repository.go

@@ -4,10 +4,10 @@ import (
 	"context"
 	"strings"
 
+	bk_io "github.com/buildkite/cli/v3/internal/io"
 	"github.com/buildkite/cli/v3/internal/pipeline"
 	"github.com/buildkite/cli/v3/pkg/cmd/factory"
 	buildkite "github.com/buildkite/go-buildkite/v4"
-	"github.com/charmbracelet/huh/spinner"
 	git "github.com/go-git/go-git/v5"
 )
 
@@ -19,12 +19,9 @@ func ResolveFromRepository(f *factory.Factory, picker PipelinePicker) PipelineRe
 	return func(ctx context.Context) (*pipeline.Pipeline, error) {
 		var err error
 		var pipelines []pipeline.Pipeline
-		spinErr := spinner.New().
-			Title("Resolving pipeline").
-			Action(func() {
-				pipelines, err = resolveFromRepository(ctx, f)
-			}).
-			Run()
+		spinErr := bk_io.SpinWhile("Resolving pipeline", func() {
+			pipelines, err = resolveFromRepository(ctx, f)
+		})
 		if spinErr != nil {
 			return nil, spinErr
 		}

pkg/cmd/agent/stop.go

@@ -4,6 +4,8 @@ import (
 	"bufio"
 	"context"
 	"errors"
+	"fmt"
+	"os"
 	"strings"
 	"sync"
 
@@ -12,6 +14,7 @@ import (
 	bk_io "github.com/buildkite/cli/v3/internal/io"
 	"github.com/buildkite/cli/v3/pkg/cmd/factory"
 	tea "github.com/charmbracelet/bubbletea"
+	"github.com/mattn/go-isatty"
 	"github.com/spf13/cobra"
 	"golang.org/x/sync/semaphore"
 )
@@ -88,6 +91,54 @@ func RunStop(cmd *cobra.Command, args []string, opts *AgentStopOptions) error {
 		return errors.New("must supply agents to stop")
 	}
 
+	// If no TTY is available, run in non-interactive mode
+	if !isatty.IsTerminal(os.Stdout.Fd()) {
+		// Directly execute the stop operations synchronously
+		var failed []string
+		var agentIDs []string
+
+		// Use the same logic as the original: either stdin OR args
+		if bk_io.HasDataAvailable(cmd.InOrStdin()) {
+			scanner := bufio.NewScanner(cmd.InOrStdin())
+			scanner.Split(bufio.ScanLines)
+			for scanner.Scan() {
+				agentID := scanner.Text()
+				if strings.TrimSpace(agentID) != "" {
+					agentIDs = append(agentIDs, agentID)
+				}
+			}
+			if scanner.Err() != nil {
+				return scanner.Err()
+			}
+		} else if len(args) > 0 {
+			agentIDs = args
+		} else {
+			return errors.New("must supply agents to stop")
+		}
+
+		// Process all agent IDs
+		for _, agentID := range agentIDs {
+			if strings.TrimSpace(agentID) != "" {
+				org, id := parseAgentArg(agentID, opts.f.Config)
+				_, err := opts.f.RestAPIClient.Agents.Stop(cmd.Context(), org, id, opts.force)
+				if err != nil {
+					failed = append(failed, fmt.Sprintf("Failed to stop agent %s: %v", agentID, err))
+				} else {
+					fmt.Fprintf(cmd.OutOrStdout(), "Stopped agent %s\n", agentID)
+				}
+			}
+		}
+
+		if len(failed) > 0 {
+			for _, failure := range failed {
+				fmt.Fprintf(cmd.ErrOrStderr(), "%s\n", failure)
+			}
+			return errors.New("at least one agent failed to stop")
+		}
+		return nil
+	}
+
+	// TTY is available, use interactive mode with Bubble Tea
 	bulkAgent := agent.BulkAgent{
 		Agents: agents,
 	}

pkg/cmd/agent/view.go

@@ -5,9 +5,9 @@ import (
 
 	"github.com/MakeNowJust/heredoc"
 	"github.com/buildkite/cli/v3/internal/agent"
+	bk_io "github.com/buildkite/cli/v3/internal/io"
 	"github.com/buildkite/cli/v3/pkg/cmd/factory"
 	buildkite "github.com/buildkite/go-buildkite/v4"
-	"github.com/charmbracelet/huh/spinner"
 	"github.com/pkg/browser"
 	"github.com/spf13/cobra"
 )
@@ -37,12 +37,9 @@ func NewCmdAgentView(f *factory.Factory) *cobra.Command {
 
 			var err error
 			var agentData buildkite.Agent
-			spinErr := spinner.New().
-				Title("Loading agent").
-				Action(func() {
-					agentData, _, err = f.RestAPIClient.Agents.Get(cmd.Context(), org, id)
-				}).
-				Run()
+			spinErr := bk_io.SpinWhile("Loading agent", func() {
+				agentData, _, err = f.RestAPIClient.Agents.Get(cmd.Context(), org, id)
+			})
 			if spinErr != nil {
 				return spinErr
 			}