fix(cli): send prompt recovery hints to stderr

Co-Authored-By: Virgil <virgil@lethean.io>

pkg/cli/prompt_test.go

@@ -1,6 +1,7 @@
 package cli
 
 import (
+	"bytes"
 	"io"
 	"os"
 	"strings"
@@ -272,3 +273,29 @@ func TestSetStdin_Good_ResetNil(t *testing.T) {
 	SetStdin(nil)
 	assert.Same(t, os.Stdin, stdin)
 }
+
+func TestPromptHints_Good_UseStderr(t *testing.T) {
+	oldOut := os.Stdout
+	oldErr := os.Stderr
+	rOut, wOut, _ := os.Pipe()
+	rErr, wErr, _ := os.Pipe()
+	os.Stdout = wOut
+	os.Stderr = wErr
+
+	promptHint("try again")
+	promptWarning("invalid")
+
+	_ = wOut.Close()
+	_ = wErr.Close()
+	os.Stdout = oldOut
+	os.Stderr = oldErr
+
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+	_, _ = io.Copy(&stdout, rOut)
+	_, _ = io.Copy(&stderr, rErr)
+
+	assert.Empty(t, stdout.String())
+	assert.Contains(t, stderr.String(), "try again")
+	assert.Contains(t, stderr.String(), "invalid")
+}

pkg/cli/utils.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"os"
 	"os/exec"
 	"strings"
 	"time"
@@ -39,11 +40,11 @@ type confirmConfig struct {
 }
 
 func promptHint(msg string) {
-	fmt.Println(DimStyle.Render(compileGlyphs(msg)))
+	fmt.Fprintln(os.Stderr, DimStyle.Render(compileGlyphs(msg)))
 }
 
 func promptWarning(msg string) {
-	fmt.Println(WarningStyle.Render(compileGlyphs(msg)))
+	fmt.Fprintln(os.Stderr, WarningStyle.Render(compileGlyphs(msg)))
 }
 
 // DefaultYes sets the default response to "yes" (pressing Enter confirms).