Function TestDebugFileSink_SurvivesAddMode

utils/log/logger_test.go:387–425

TestDebugFileSink_SurvivesAddMode is the regression test for the empty-per-test-set-file bug: AddMode rebuilds the core from scratch and the file-sink tee was being silently discarded. Without reattachDebugFileSink in AddMode, the second log record would not appear in the file.

(t *testing.T)

// reattachDebugFileSink in AddMode, the second log record would not
// appear in the file.
func TestDebugFileSink_SurvivesAddMode(t *testing.T) {
	SetRedactor(nil)
	console := &syncBuffer{}
	logger := newConsoleLogger(console, zap.InfoLevel)

	tmp, err := os.CreateTemp(t.TempDir(), "addmode-*.log")
	if err != nil {
		t.Fatalf("create temp: %v", err)
	}
	defer tmp.Close()
	wrapped, sink := AddDebugFileSink(logger, tmp, 0)
	SetDebugFileSink(sink)
	defer SetDebugFileSink(nil)

	wrapped.Debug("before-addmode")

	// Simulate the agent CLI's Validate path: AddMode mutates the live
	// logger via *logger = *new (the same pointee-overwrite pattern
	// the codebase uses everywhere).
	rebuilt, err := AddMode("agent")
	if err != nil {
		t.Fatalf("AddMode: %v", err)
	}
	*wrapped = *rebuilt

	wrapped.Debug("after-addmode")

	if err := sink.Flush(); err != nil {
		t.Fatalf("flush: %v", err)
	}
	contents, _ := os.ReadFile(tmp.Name())
	got := string(contents)
	if !strings.Contains(got, "before-addmode") {
		t.Errorf("before-addmode missing from file: %s", got)
	}
	if !strings.Contains(got, "after-addmode") {
		t.Errorf("after-addmode missing from file (the regression): %s", got)
	}
}

// TestDebugFileSink_RotateAfterAddMode confirms that rotation still
// works after the logger has been rebuilt — the buffered+capped