better labs command alignment

cmd/entire/cli/labs.go

@@ -3,6 +3,7 @@ package cli
 import (
 	"fmt"
 	"strings"
+	"unicode/utf8"
 
 	"github.com/spf13/cobra"
 )
@@ -94,10 +95,17 @@ Try:
 }
 
 func renderExperimentalCommands(commands []experimentalCommandInfo) string {
+	width := 0
+	for _, info := range commands {
+		if w := utf8.RuneCountInString(info.Invocation); w > width {
+			width = w
+		}
+	}
+
 	var out strings.Builder
 	for _, info := range commands {
 		out.WriteString("  ")
-		out.WriteString(padRight(info.Invocation, 16))
+		out.WriteString(padRight(info.Invocation, width))
 		out.WriteByte(' ')
 		out.WriteString(info.Summary)
 		out.WriteByte('\n')
@@ -106,8 +114,9 @@ func renderExperimentalCommands(commands []experimentalCommandInfo) string {
 }
 
 func padRight(value string, width int) string {
-	if len(value) >= width {
+	n := utf8.RuneCountInString(value)
+	if n >= width {
 		return value
 	}
-	return value + strings.Repeat(" ", width-len(value))
+	return value + strings.Repeat(" ", width-n)
 }

cmd/entire/cli/labs_test.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"strings"
 	"testing"
+	"unicode/utf8"
 )
 
 func TestLabsCmd_PrintsExperimentalCommandList(t *testing.T) {
@@ -97,6 +98,95 @@ func TestRootHelp_ShowsLabsButHidesReview(t *testing.T) {
 	}
 }
 
+// summaryColumns returns, for each non-empty rendered row, the rune offset at
+// which the summary begins (i.e. the column after the padded invocation).
+func summaryColumns(t *testing.T, commands []experimentalCommandInfo) []int {
+	t.Helper()
+	var cols []int
+	for _, line := range strings.Split(renderExperimentalCommands(commands), "\n") {
+		if line == "" {
+			continue
+		}
+		info := indexOfSummary(t, line, commands)
+		cols = append(cols, info)
+	}
+	return cols
+}
+
+// indexOfSummary finds the rune offset of a row's summary text within the line.
+func indexOfSummary(t *testing.T, line string, commands []experimentalCommandInfo) int {
+	t.Helper()
+	for _, info := range commands {
+		if idx := strings.Index(line, info.Summary); idx >= 0 {
+			return utf8.RuneCountInString(line[:idx])
+		}
+	}
+	t.Fatalf("no known summary found in rendered line %q", line)
+	return -1
+}
+
+func TestRenderExperimentalCommands_SummariesAlign(t *testing.T) {
+	t.Parallel()
+
+	cols := summaryColumns(t, experimentalCommands)
+	if len(cols) < 2 {
+		t.Fatalf("expected multiple experimental commands, got %d", len(cols))
+	}
+	for i, col := range cols {
+		if col != cols[0] {
+			t.Fatalf("summary column %d (%d) does not match first column (%d); descriptions are misaligned", i, col, cols[0])
+		}
+	}
+}
+
+func TestRenderExperimentalCommands_ColumnWidthAdjustsToLongest(t *testing.T) {
+	t.Parallel()
+
+	short := []experimentalCommandInfo{
+		{Name: "a", Invocation: "entire a", Summary: "first"},
+		{Name: "b", Invocation: "entire b", Summary: "second"},
+	}
+	long := []experimentalCommandInfo{
+		{Name: "a", Invocation: "entire a", Summary: "first"},
+		{Name: "verylongcommand", Invocation: "entire verylongcommand", Summary: "second"},
+	}
+
+	shortCol := summaryColumns(t, short)[0]
+	longCol := summaryColumns(t, long)[0]
+
+	if longCol <= shortCol {
+		t.Fatalf("column should widen for a longer invocation: short=%d long=%d", shortCol, longCol)
+	}
+	// All rows in the long set must still align despite differing invocation lengths.
+	for i, col := range summaryColumns(t, long) {
+		if col != longCol {
+			t.Fatalf("row %d column %d does not match %d", i, col, longCol)
+		}
+	}
+}
+
+func TestRenderExperimentalCommands_MultiByteInvocationAligns(t *testing.T) {
+	t.Parallel()
+
+	// "entire ▶▶" is 9 runes but 13 bytes (each ▶ is 3 bytes). The longest
+	// invocation below is 12 runes, so the column width is 12. With byte-based
+	// padding, len("entire ▶▶") == 13 >= 12 would skip padding and misalign the
+	// row; rune-based padding correctly adds 3 spaces.
+	commands := []experimentalCommandInfo{
+		{Name: "long", Invocation: "entire aaaaa", Summary: "first"},
+		{Name: "multibyte", Invocation: "entire ▶▶", Summary: "second"},
+	}
+
+	if got := len("entire ▶▶"); got < 12 {
+		t.Fatalf("test precondition broken: byte length %d should exceed column width 12", got)
+	}
+
+	cols := summaryColumns(t, commands)
+	if cols[0] != cols[1] {
+		t.Fatalf("multi-byte invocation summary misaligned: %v", cols)
+	}
+}
+
 func TestLabsRegistryCommandsExistAtCanonicalPaths(t *testing.T) {
 	t.Parallel()