Currently, if you use oxc_diagnostics with GraphicalReportHandler, and you print to a non-terminal, the output will contain color escape codes, even with NO_COLOR=1. This is because if stdout or stderr are not a terminal, GraphicalTheme::default() will return GraphicalTheme::ascii() regardless of the NO_COLOR value, and ascii() does have colors. This means that when printing to a non-terminal, there is no way to turn off the color escapes.

When printing to a non-terminal, you usually don't want color output, so presumably the default GraphicalTheme on non-terminals should be GraphicalTheme::none(). But in some cases it might be useful to enable color, even if not by default. Maybe FORCE_COLOR could be used in that case.