fix: expand grouped log lines when copying to clipboard (#4771)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

internal/container/sanitize.go

@@ -2,18 +2,20 @@ package container
 
 import "strings"
 
-// stripControlBytes removes C0 control characters except tab (\x09), newline
-// (\x0a) and carriage return (\x0d). A NUL byte terminates the clipboard string
-// on Windows, dropping everything after it.
-func stripControlBytes(r rune) rune {
-	if (r >= 0x00 && r <= 0x08) || r == 0x0b || r == 0x0c || (r >= 0x0e && r <= 0x1f) {
-		return -1
+// PlainText renders a log event as plain text for clipboard copy, stripping
+// ANSI escape sequences. Grouped events carry their lines in fragments and
+// have an empty RawMessage, so they are expanded one line per fragment;
+// otherwise every grouped multi-line entry collapses to a single blank line on
+// copy.
+func (e *LogEvent) PlainText() string {
+	if e.Type == LogTypeGroup {
+		if fragments, ok := e.Message.([]LogFragment); ok {
+			lines := make([]string, len(fragments))
+			for i, fragment := range fragments {
+				lines[i] = StripANSI(fragment.Message)
+			}
+			return strings.Join(lines, "\n")
+		}
 	}
-	return r
-}
-
-// SanitizeForPlainText strips ANSI escape sequences and control bytes so log
-// text is safe to copy to the clipboard or open in a text editor.
-func SanitizeForPlainText(str string) string {
-	return strings.Map(stripControlBytes, StripANSI(str))
+	return StripANSI(e.RawMessage)
 }

internal/container/sanitize_test.go

@@ -2,23 +2,48 @@ package container
 
 import "testing"
 
-func TestSanitizeForPlainText(t *testing.T) {
+func TestLogEventPlainText(t *testing.T) {
 	tests := []struct {
 		name     string
-		input    string
+		event    *LogEvent
 		expected string
 	}{
-		{"strips NUL bytes that truncate clipboard text on Windows", "before\x00after", "beforeafter"},
-		{"strips other C0 control bytes", "a\x01b\x07c\x1fd", "abcd"},
-		{"preserves tab, newline and carriage return", "a\tb\nc\r\nd", "a\tb\nc\r\nd"},
-		{"removes ANSI escape sequences", "\x1b[31mred\x1b[0m text", "red text"},
-		{"leaves plain text untouched", "plain log line", "plain log line"},
+		{
+			name:     "single event returns ANSI-stripped raw message",
+			event:    &LogEvent{Type: LogTypeSingle, RawMessage: "\x1b[31mred\x1b[0m text"},
+			expected: "red text",
+		},
+		{
+			name:     "complex event returns raw message",
+			event:    &LogEvent{Type: LogTypeComplex, RawMessage: `{"level":"info"}`},
+			expected: `{"level":"info"}`,
+		},
+		{
+			name: "grouped event expands every fragment line (otherwise lost on copy)",
+			event: &LogEvent{
+				Type: LogTypeGroup,
+				Message: []LogFragment{
+					{Message: "Job (17) starting"},
+					{Message: "Job (17) done in 0.006s"},
+					{Message: "Job (17) completed"},
+				},
+			},
+			expected: "Job (17) starting\nJob (17) done in 0.006s\nJob (17) completed",
+		},
+		{
+			name: "grouped fragments are ANSI-stripped",
+			event: &LogEvent{
+				Type:    LogTypeGroup,
+				Message: []LogFragment{{Message: "\x1b[31mred\x1b[0m"}, {Message: "plain"}},
+			},
+			expected: "red\nplain",
+		},
 	}
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			if got := SanitizeForPlainText(tt.input); got != tt.expected {
-				t.Errorf("SanitizeForPlainText(%q) = %q, want %q", tt.input, got, tt.expected)
+			if got := tt.event.PlainText(); got != tt.expected {
+				t.Errorf("PlainText() = %q, want %q", got, tt.expected)
 			}
 		})
 	}

internal/web/logs.go

@@ -197,8 +197,10 @@ func (h *handler) fetchLogsBetweenDates(w http.ResponseWriter, r *http.Request)
 					}
 				}
 				if plainText {
-					// Strip ANSI and control bytes; a NUL byte truncates clipboard text on Windows
-					fmt.Fprintf(writer, "%s\n", container.SanitizeForPlainText(event.RawMessage))
+					// Expand grouped events into their fragment lines; grouped
+					// events store their lines in Message and have an empty
+					// RawMessage, so writing RawMessage alone drops every group.
+					fmt.Fprintf(writer, "%s\n", event.PlainText())
 				} else if err := encoder.Encode(event); err != nil {
 					log.Error().Err(err).Msg("error encoding log event")
 				}