Fix tctl access-review table from overflowing terminal width (#190)

Export-Source-Commit: 5c488f3ad10371625e4ad061c4d3ef0dd9702995

lib/asciitable/table.go

@@ -33,6 +33,17 @@ import (
 	"golang.org/x/term"
 )
 
+// Layout constants, for callers sizing columns against a terminal width: a
+// column occupies max(MinColumnWidth, widest cell+ColumnPadding).
+const (
+	// MinColumnWidth is the narrowest a column renders, whatever its contents.
+	MinColumnWidth = 5
+	// ColumnPadding follows every cell, including the last one on a row.
+	ColumnPadding = 1
+	// TruncationSuffix is appended to cells over [Column.MaxCellLength].
+	TruncationSuffix = "..."
+)
+
 // Column represents a column in the table.
 type Column struct {
 	Title         string
@@ -103,16 +114,16 @@ func MakeTableWithTruncatedColumn(columnOrder []string, rows [][]string, truncat
 		}
 		if column.MaxCellLength > maxColWidth {
 			column.MaxCellLength = maxColWidth
-			totalLen += column.MaxCellLength + 4 // "...<space>"
+			totalLen += column.MaxCellLength + len(TruncationSuffix) + ColumnPadding // "...<space>"
 		} else {
-			totalLen += column.MaxCellLength + 1 // +1 for column separator
+			totalLen += column.MaxCellLength + ColumnPadding // +1 for column separator
 		}
 		columns = append(columns, column)
 	}
 
 	for _, column := range columns {
 		if column.Title == truncatedColumn {
-			column.MaxCellLength = max(width-totalLen-len("... "), 0)
+			column.MaxCellLength = max(width-totalLen-len(TruncationSuffix)-ColumnPadding, 0)
 		}
 		t.AddColumn(column)
 	}
@@ -151,7 +162,7 @@ func (t *Table) truncateCell(colIndex int, cell string) (string, bool) {
 	if maxCellLength == 0 || len(cell) <= maxCellLength {
 		return cell, false
 	}
-	truncatedCell := fmt.Sprintf("%v...", cell[:maxCellLength])
+	truncatedCell := cell[:maxCellLength] + TruncationSuffix
 	footnoteLabel := t.columns[colIndex].FootnoteLabel
 	if footnoteLabel == "" {
 		return truncatedCell, false
@@ -179,7 +190,7 @@ func (t *Table) String() string {
 
 // WriteTo writes the full table to [w] or else returns an error.
 func (t *Table) WriteTo(w io.Writer) error {
-	writer := tabwriter.NewWriter(w, 5, 0, 1, ' ', 0)
+	writer := tabwriter.NewWriter(w, MinColumnWidth, 0, ColumnPadding, ' ', 0)
 	template := strings.Repeat("%v\t", len(t.columns))
 
 	// Header and separator.

tool/tctl/common/accessgraph/access_review_command.go

@@ -125,7 +125,7 @@ func (c *AccessGraphCommand) AccessReview(ctx context.Context, client *accessgra
 		output.ActivityUnavailable = utils.AllowWhitespace(*resp.IacError)
 	}
 	if truncated {
-		output.Warnings = append(output.Warnings, fmt.Sprintf("results truncated at %d identities; narrow --query for the full set", args.limit))
+		output.Warnings = append(output.Warnings, fmt.Sprintf("results truncated at %d identities; narrow --query or increase --limit for the full set", args.limit))
 	}
 
 	return writeOutput(c.stdout, output, args.format, func(w io.Writer) error {
@@ -501,9 +501,12 @@ func accessReviewDetailedRows(output accessReviewOutput, showActivity bool) ([]s
 	return headers, rows
 }
 
-const resourceColumn = "Resource"
-
-const resourceColumnFloor = 16
+const (
+	// resourceColumn is the header of the column we truncate to fit the terminal.
+	resourceColumn = "Resource"
+	// resourceColumnFloor is the narrowest we will truncate resourceColumn to.
+	resourceColumnFloor = 16
+)
 
 func writeAccessTable(out io.Writer, headers []string, rows [][]string) error {
 	table := buildAccessTable(headers, rows, terminalWidth(out))
@@ -511,30 +514,39 @@ func writeAccessTable(out io.Writer, headers []string, rows [][]string) error {
 	return trace.Wrap(err)
 }
 
-// buildAccessTable caps only the Resource column to the space the others leave,
-// so wide columns are never clipped just to fit the table width. The cap ignores
-// the "..." asciitable appends on truncation, so a clipped Resource can overflow
-// width by a few columns; the terminal wraps it.
+// buildAccessTable lets every column render at its full width and truncates
+// only resourceColumn to the space they leave over, so no column is clipped
+// just to fit the table width. The table exceeds width only when that space
+// falls under resourceColumnFloor, in which case the terminal wraps it.
 func buildAccessTable(headers []string, rows [][]string, width int) asciitable.Table {
-	used := 0
+	// Measure what the other columns cost, and how much room Resource wants, so
+	// we can tell whether it needs truncating at all.
+	used, resourceWidth := 0, 0
 	for i, h := range headers {
-		if h == resourceColumn {
-			continue
-		}
 		colWidth := len(h)
 		for _, row := range rows {
 			if i < len(row) && len(row[i]) > colWidth {
 				colWidth = len(row[i])
 			}
 		}
-		used += colWidth + 1 // +1 for tabwriter's column padding
+		if h == resourceColumn {
+			resourceWidth = colWidth
+			continue
+		}
+		used += max(colWidth+asciitable.ColumnPadding, asciitable.MinColumnWidth)
 	}
 
+	// Room left for Resource's own contents, its padding excluded.
+	available := width - used - asciitable.ColumnPadding
+
 	t := asciitable.MakeTable([]string{})
 	for _, h := range headers {
 		col := asciitable.Column{Title: h}
-		if h == resourceColumn {
-			col.MaxCellLength = max(width-used, resourceColumnFloor)
+		// A zero MaxCellLength leaves the column unbounded, so bound Resource
+		// only when it genuinely overflows; the suffix asciitable appends on
+		// truncation comes out of the same room.
+		if h == resourceColumn && resourceWidth > available {
+			col.MaxCellLength = max(available-len(asciitable.TruncationSuffix), resourceColumnFloor)
 		}
 		t.AddColumn(col)
 	}