Refaster support for varargs methods

I tried to write a Refaster rule for callers of some internal library method M which has a signature that matches String#format(String, Object...). The idea is to identify callers which explicitly call String.format before invoking M and to rewrite those expressions to defer the formatting to M. But nothing happened.

This appears to be because of the use of varargs. As a test I tried to apply the following dummy Refaster template to our code base, but that didn’t do anything either:

final class VarargsRefasterTemplate {
    @BeforeTemplate
    String before(final String format, final Object... args) {
        return String.format(format, args);
    }

    @AfterTemplate
    String after(final String format, final Object... args) {
        return "This is a test";
    }
}

Would it be possible to support varargs?

[lowasser]

It is supported, just not in a super well documented way, I think?

Write @BeforeTemplate String before(String format, @Repeated Object arg).

@Repeated is slightly more general, though; it can be interspersed with normal arguments, put in an array declaration, and generally stand in for any comma repeated expression.

[knutwannheden]

When writing a Refaster template for a method with a varargs parameter, I currently always need to specify at least two templates: one for call sites using varargs and one for call sites using explicit arrays. Could Refaster simplify this use case?