From dd14ac9f489857da4d0d7575b6257e29bd69a562 Mon Sep 17 00:00:00 2001
From: Malcolm Barrett <malcolmbarrett@gmail.com>
Date: Sun, 3 Mar 2024 13:38:49 -0500
Subject: [PATCH] manually strip graph attribute and test for nullness

---
 R/tidy_dag.R                   | 9 +++++----
 R/utils.R                      | 8 ++++++++
 tests/testthat/test-tidy_dag.R | 5 +++++
 3 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/R/tidy_dag.R b/R/tidy_dag.R
index e455464..dd22f94 100644
--- a/R/tidy_dag.R
+++ b/R/tidy_dag.R
@@ -278,22 +278,23 @@ generate_layout <- function(.df, layout, vertices = NULL, coords = NULL, ...) {
 
 
   if (no_existing_coords) {
-    ggraph_layout <- suppressMessages(ggraph::create_layout(
+    ggraph_layout <- ggraph_create_layout(
       ig,
       layout = layout,
       ...
-    ))
+    )
+
   } else {
     nodes <- names(igraph::V(ig))
     coords$x <- coords$x[nodes]
     coords$y <- coords$y[nodes]
-    ggraph_layout <- suppressMessages(ggraph::create_layout(
+    ggraph_layout <- ggraph_create_layout(
       ig,
       layout = "manual",
       x = coords$x,
       y = coords$y,
       ...
-    ))
+    )
   }
 
   ggraph_layout %>%
diff --git a/R/utils.R b/R/utils.R
index e766eea..a24774a 100644
--- a/R/utils.R
+++ b/R/utils.R
@@ -201,3 +201,11 @@ check_arg_stylized <- function(stylized, use_stylized, what = "geom_dag") {
 
   use_stylized
 }
+
+ggraph_create_layout <- function(...) {
+  .df <- suppressMessages(ggraph::create_layout(...))
+  # ggdag doesn't need the igraph object
+  attr(.df, "graph") <- NULL
+
+  .df
+}
diff --git a/tests/testthat/test-tidy_dag.R b/tests/testthat/test-tidy_dag.R
index 0704390..34aa371 100644
--- a/tests/testthat/test-tidy_dag.R
+++ b/tests/testthat/test-tidy_dag.R
@@ -120,6 +120,11 @@ test_that("Forbidden layouts error", {
   )
 })
 
+test_that("igraph attribute does not hitchhike onto tidy dag", {
+  td <- tidy_dagitty(dagify(y ~ x + z, x ~ z))
+  expect_null(attr(pull_dag_data(td), "graph"))
+})
+
 expect_function_produces_name <- function(tidy_dag, column) {
   .df <- pull_dag_data(tidy_dag)
   expect_true(all(column %in% names(.df)))