Cant parse variable arguments ...

[liuzhenghua]

Steps to reproduce

class Test{
    @SafeVarargs
    public static @Nullable <T extends PsiElement> T getPrevSiblingOfType(@Nullable PsiElement element
            , @NotNull Class<? extends T> @NotNull ... classes) {
        PsiElement run = element;
        while (run != null) {
            if (PsiTreeUtil.instanceOf(run, classes)) {
                return (T)run;
            }
            if (run instanceof PsiFile) break;
            run = run.getPrevSibling();
        }
        return null;
    }
}

classes param parsed as ERROR node type.

[amaanq]

In the future, please provide minimal (!) code snippets as reproducers, with steps to reproduce outside of a 3rd party environment/tool. It costs me time to whittle the snippets down and figure out the actual issue, as an opaque screenshot isn't super helpful.

[liuzhenghua]

...

Thank you for your feedback. I appreciate the time you’ve taken to investigate the issue.

The root cause of this issue is that Treesitter cannot parse variadic arguments in Java. When using Treesitter's API to parse the provided class file, the type of the last parameter is parsed as ERROR (likely because the syntax file does not account for the ... character).

[liuzhenghua]

Here is the python code to reproduce this:

_JAVA_LANG = Language(tsjava.language())
_JAVA_PARSER = Parser(_JAVA_LANG)

file_content = """
class Test{
    @SafeVarargs
    public static @Nullable <T extends PsiElement> T getPrevSiblingOfType(@Nullable PsiElement element
            , @NotNull Class<? extends T> @NotNull ... classes) {
        PsiElement run = element;
        while (run != null) {
            if (PsiTreeUtil.instanceOf(run, classes)) {
                return (T)run;
            }
            if (run instanceof PsiFile) break;
            run = run.getPrevSibling();
        }
        return null;
    }
}
"""
tree = cls._JAVA_PARSER.parse(bytes(file_content, "utf-8"))

You can also using tree sitter playground to reproduce this issue:

[amaanq]

Yeah no Python code doesn't cut it, but the playground is great to showcase an issue. A minimal reproducer would look like this:

class A {
	public static void a(int @NotNull... arg) {
	}
}

This clearly shows the same error and doesn't have a bunch of other unrelated code alongside it.