Responding to a request with slices

[tadeokondrak]

Some request results have slices, like textDocument/hover's MarkupContent.

When using lsp.Connection, the signature is

pub fn @"textDocument/hover"(conn: *Connection, id: lsp.types.RequestId, params: lsp.types.HoverParams) !lsp.types.Hover

If I set up an arena allocator inside the implementation, the memory returned becomes invalid. Is there a simple way to do this without leaking memory?

[dstrachan]

You should take a look at implementing lspRecvPre and lspRecvPost hooks which will be called before and after your textDocument/hover request.

zig-lsp/src/zig_lsp.zig

Lines 314 to 320 in d89ebda

	if (@hasDecl(ContextType, "lspRecvPre")) try ContextType.lspRecvPre(conn, req.method, .request, id, value);
	try conn.respond(req.method, id, @field(ContextType, req.method)(conn, id, value) catch |err| {
	try conn.respondError(arena, id, err, @errorReturnTrace());
	if (@hasDecl(ContextType, "lspRecvPost")) try ContextType.lspRecvPost(conn, req.method, .request, id, value);
	return;
	});
	if (@hasDecl(ContextType, "lspRecvPost")) try ContextType.lspRecvPost(conn, req.method, .request, id, value);