Show a blank prompt glyph until invalid input is edited

.nextchanges/cli/prompt-blank-glyph.md

@@ -0,0 +1 @@
+* Prompts that validate their input, such as the `databricks configure` host prompt, no longer open with a red cross before anything is typed. ([#7314](https://github.com/databricks/cli/pull/7314))

libs/cmdio/cmdiotest/prompt_validate_baseline_test.go

@@ -45,3 +45,90 @@ func TestPromptBaseline_Validate(t *testing.T) {
 	require.NoError(t, err, "raw output: %q", tm.Raw())
 	assert.Equal(t, "https://example.com", v, "snapshot:\n%s", tm.Snapshot())
 }
+
+// TestPromptBaseline_ValidateEnterBeforeEdit pins that Enter on an untouched
+// prompt flips the glyph to "✗" along with the error line.
+func TestPromptBaseline_ValidateEnterBeforeEdit(t *testing.T) {
+	t.Parallel()
+	tm := termtest.NewPrompt(t, cmdio.PromptOptions{
+		Label: "Workspace host",
+		Validate: func(s string) error {
+			if s == "" {
+				return errors.New("host is required")
+			}
+			return nil
+		},
+	})
+	tm.WaitFor("Workspace host")
+	tm.Type(termtest.KeyEnter)
+	tm.Golden("01-enter")
+
+	tm.Type(termtest.KeyCtrlC)
+	_, err := tm.Result()
+	require.Error(t, err)
+	assert.EqualError(t, err, "^C")
+}
+
+// TestPromptBaseline_ValidateValidBeforeEdit pins that an untouched prompt
+// whose input already passes Validate shows "✔".
+func TestPromptBaseline_ValidateValidBeforeEdit(t *testing.T) {
+	t.Parallel()
+	tm := termtest.NewPrompt(t, cmdio.PromptOptions{
+		Label: "Workspace host",
+		Validate: func(s string) error {
+			if strings.Contains(s, " ") {
+				return errors.New("must not contain spaces")
+			}
+			return nil
+		},
+	})
+	tm.WaitFor("Workspace host")
+	tm.Golden("01-initial")
+
+	tm.Type(termtest.KeyEnter)
+	v, err := tm.Result()
+	require.NoError(t, err, "raw output: %q", tm.Raw())
+	assert.Empty(t, v)
+}
+
+// TestPromptBaseline_ValidateNonEditKeysKeepBlankGlyph pins that keys which
+// leave the buffer unchanged do not flip the blank glyph to "✗".
+func TestPromptBaseline_ValidateNonEditKeysKeepBlankGlyph(t *testing.T) {
+	t.Parallel()
+	tm := termtest.NewPrompt(t, cmdio.PromptOptions{
+		Label: "Workspace host",
+		Validate: func(s string) error {
+			if s == "" {
+				return errors.New("host is required")
+			}
+			return nil
+		},
+	})
+	tm.WaitFor("Workspace host")
+	tm.Type(termtest.KeyLeft + termtest.KeyRight + termtest.KeyBackspace + termtest.KeyCtrlC)
+	_, err := tm.Result()
+	assert.EqualError(t, err, "^C")
+	// The prompt line is erased on exit, so check every rendered frame.
+	assert.NotContains(t, tm.Raw(), "✗")
+}
+
+// TestPromptBaseline_ValidateEmptyPasteKeepsBlankGlyph pins that an empty
+// bracketed paste, which some terminals send for an empty clipboard, is not
+// treated as an edit.
+func TestPromptBaseline_ValidateEmptyPasteKeepsBlankGlyph(t *testing.T) {
+	t.Parallel()
+	tm := termtest.NewPrompt(t, cmdio.PromptOptions{
+		Label: "Workspace host",
+		Validate: func(s string) error {
+			if s == "" {
+				return errors.New("host is required")
+			}
+			return nil
+		},
+	})
+	tm.WaitFor("Workspace host")
+	tm.Type("\x1b[200~\x1b[201~" + termtest.KeyCtrlC)
+	_, err := tm.Result()
+	assert.EqualError(t, err, "^C")
+	assert.NotContains(t, tm.Raw(), "✗")
+}

libs/cmdio/cmdiotest/testdata/TestPromptBaseline_Validate/01-empty.golden

@@ -1 +1 @@
-✗ Workspace host: █
+  Workspace host: █

libs/cmdio/cmdiotest/testdata/TestPromptBaseline_ValidateEnterBeforeEdit/01-enter.golden

@@ -0,0 +1,2 @@
+✗ Workspace host: █
+>> host is required

libs/cmdio/cmdiotest/testdata/TestPromptBaseline_ValidateValidBeforeEdit/01-initial.golden

@@ -0,0 +1 @@
+✔ Workspace host: █

libs/cmdio/prompt.go

@@ -10,11 +10,13 @@ import (
 )
 
 // Glyphs drawn into the prompt's rendered output. cursorBlock stands in for
-// the (hidden) OS cursor at the current edit position.
+// the (hidden) OS cursor at the current edit position. The glyphs must all be
+// one column wide so the label does not shift when the glyph changes.
 const (
 	cursorBlock  = "█"
 	glyphValid   = "✔"
 	glyphInvalid = "✗"
+	glyphBlank   = " "
 )
 
 // PromptOptions configures a single-line text prompt shown by [RunPrompt].
@@ -33,7 +35,9 @@ type PromptOptions struct {
 	// Validate, when set, is called on every keystroke. While it returns a
 	// non-nil error the leading glyph flips from "✔" to "✗" and Enter is
 	// inert; pressing Enter while invalid surfaces the returned error
-	// below the prompt until the next edit.
+	// below the prompt until the next edit. Until the first edit or Enter,
+	// an invalid input shows a blank glyph instead, so an empty prompt does
+	// not open as an error.
 	Validate func(input string) error
 }
 
@@ -73,6 +77,10 @@ type promptModel struct {
 	deleted   bool
 	submitted bool
 
+	// touched is set by the first edit or Enter. Until then an invalid input
+	// shows a blank glyph, so a required field does not open as an error.
+	touched bool
+
 	// submitErr is the error from the last failed Enter attempt. Rendered
 	// below the prompt and cleared on the next edit.
 	submitErr error
@@ -92,12 +100,16 @@ func (m *promptModel) value() string {
 }
 
 // glyph returns the leading status indicator: bold-green ✔ when valid,
-// bold-red ✗ when validate rejects the buffer.
+// bold-red ✗ when validate rejects the buffer after an edit or Enter, and a
+// blank before that.
 func (m *promptModel) glyph() string {
-	if m.validate != nil && m.validate(m.value()) != nil {
-		return ansiBold + ansiRed + glyphInvalid + ansiReset
+	if m.validate == nil || m.validate(m.value()) == nil {
+		return ansiBold + ansiGreen + glyphValid + ansiReset
+	}
+	if !m.touched {
+		return glyphBlank
 	}
-	return ansiBold + ansiGreen + glyphValid + ansiReset
+	return ansiBold + ansiRed + glyphInvalid + ansiReset
 }
 
 func (m *promptModel) Init() tea.Cmd { return nil }
@@ -115,6 +127,7 @@ func (m *promptModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 
 	case tea.KeyEnter, tea.KeyCtrlJ:
 		// Enter sends CR, Ctrl+J sends LF; treat both as submit.
+		m.touched = true
 		if m.validate != nil {
 			if err := m.validate(m.value()); err != nil {
 				m.submitErr = err
@@ -168,10 +181,17 @@ func (m *promptModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		if key.Type == tea.KeySpace {
 			typed = []rune{' '}
 		}
+		// Some terminals send an empty bracketed paste when the clipboard is
+		// empty. Nothing changes, so it must not count as an edit or clear the
+		// error line.
+		if len(typed) == 0 {
+			return m, nil
+		}
 		tail := append([]rune{}, m.runes[m.cursor:]...)
 		m.runes = append(m.runes[:m.cursor], typed...)
 		m.runes = append(m.runes, tail...)
 		m.cursor += len(typed)
+		m.touched = true
 		m.submitErr = nil
 
 	default: