From 400f64031da1954d0767f00a9cef3b76d9a7d259 Mon Sep 17 00:00:00 2001
From: Nicolas Bennett <3158446+nbenn@users.noreply.github.com>
Date: Wed, 23 Oct 2024 10:46:31 +0200
Subject: [PATCH] allow evaluate null

---
 R/block-core.R | 9 +++++++--
 R/server.R     | 4 ++--
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/R/block-core.R b/R/block-core.R
index 452b6366..b739837f 100644
--- a/R/block-core.R
+++ b/R/block-core.R
@@ -220,13 +220,18 @@ generate_code.call <- function(x) {
 #' @inherit new_block
 #' @param ... For generic consistency.
 #' @export
-evaluate_block <- function(x, ...) {
+evaluate_block <- function(x, data, ...) {
+
+  if (!missing(data) && is.null(data)) {
+    return(NULL)
+  }
+
   UseMethod("evaluate_block")
 }
 
 #' @rdname evaluate_block
 #' @export
-evaluate_block.data_block <- function(x, ...) {
+evaluate_block.data_block <- function(x, data, ...) {
 
   stopifnot(...length() == 0L)
 
diff --git a/R/server.R b/R/server.R
index 4ffc81b8..0bf5bc6c 100644
--- a/R/server.R
+++ b/R/server.R
@@ -212,7 +212,7 @@ generate_server_block <- function(
           {
             if (!is_valid$block) {
               NULL
-            } else if (is.null(in_dat()) && !inherits(x, "transform_block")) {
+            } else if (inherits(x, "dataset_block")) {
               evaluate_block(blk())
             } else {
               evaluate_block(blk(), data = in_dat())
@@ -226,7 +226,7 @@ generate_server_block <- function(
         reactive({
           if (!is_valid$block) {
             NULL
-          } else if (is.null(in_dat()) && !inherits(x, "transform_block")) {
+          } else if (inherits(x, "dataset_block")) {
             evaluate_block(blk())
           } else {
             evaluate_block(blk(), data = in_dat())