From 193825004dbbefded15cd979a453f124d682907a Mon Sep 17 00:00:00 2001
From: schochastics <david@schochastics.net>
Date: Tue, 24 Jun 2025 10:53:57 +0200
Subject: [PATCH 1/3] added warning

---
 R/plot.R | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/R/plot.R b/R/plot.R
index 43c75141150..f3f881fb3d1 100644
--- a/R/plot.R
+++ b/R/plot.R
@@ -135,6 +135,11 @@ plot.igraph <- function(
   }
 
   layout <- i.postprocess.layout(params("plot", "layout"))
+  if (nrow(layout) != vc) {
+    cli::cli_warn(
+      "The layout has {nrow(layout)} rows, but the graph has {vc} vertices. Unintended results may occur."
+    )
+  }
   margin <- params("plot", "margin")
   margin <- rep(margin, length.out = 4)
   rescale <- params("plot", "rescale")

From db4f62ae3735f068727d4f32b2465ab6d953b27b Mon Sep 17 00:00:00 2001
From: schochastics <david@schochastics.net>
Date: Tue, 24 Jun 2025 20:13:40 +0200
Subject: [PATCH 2/3] augmented error message

---
 R/plot.R | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/R/plot.R b/R/plot.R
index f3f881fb3d1..fbbfb274512 100644
--- a/R/plot.R
+++ b/R/plot.R
@@ -136,9 +136,9 @@ plot.igraph <- function(
 
   layout <- i.postprocess.layout(params("plot", "layout"))
   if (nrow(layout) != vc) {
-    cli::cli_warn(
-      "The layout has {nrow(layout)} rows, but the graph has {vc} vertices. Unintended results may occur."
-    )
+    cli::cli_warn(c(
+      "The layout has {nrow(layout)} rows, but the graph has {vc} vertices. Unintended results may occur.",
+    "i" = "It is recommended to store the layout as x and y vertex attributes and not as a matrix graph attribute."))
   }
   margin <- params("plot", "margin")
   margin <- rep(margin, length.out = 4)

From 24fecf386ee910f19db300b7f3e916dd9b4d25a2 Mon Sep 17 00:00:00 2001
From: schochastics <david@schochastics.net>
Date: Mon, 7 Jul 2025 14:30:37 +0200
Subject: [PATCH 3/3] made error added test

---
 R/plot.R                      | 4 ++--
 tests/testthat/_snaps/plot.md | 9 +++++++++
 tests/testthat/test-plot.R    | 8 ++++++++
 3 files changed, 19 insertions(+), 2 deletions(-)
 create mode 100644 tests/testthat/_snaps/plot.md

diff --git a/R/plot.R b/R/plot.R
index fbbfb274512..0bcd8a9a59d 100644
--- a/R/plot.R
+++ b/R/plot.R
@@ -136,8 +136,8 @@ plot.igraph <- function(
 
   layout <- i.postprocess.layout(params("plot", "layout"))
   if (nrow(layout) != vc) {
-    cli::cli_warn(c(
-      "The layout has {nrow(layout)} rows, but the graph has {vc} vertices. Unintended results may occur.",
+    cli::cli_abort(c(
+      "The layout has {nrow(layout)} rows, but the graph has {vc} vertices.",
     "i" = "It is recommended to store the layout as x and y vertex attributes and not as a matrix graph attribute."))
   }
   margin <- params("plot", "margin")
diff --git a/tests/testthat/_snaps/plot.md b/tests/testthat/_snaps/plot.md
new file mode 100644
index 00000000000..4d902f54dae
--- /dev/null
+++ b/tests/testthat/_snaps/plot.md
@@ -0,0 +1,9 @@
+# layout as graph attribute error works
+
+    Code
+      plot(g)
+    Condition
+      Error in `plot()`:
+      ! The layout has 5 rows, but the graph has 10 vertices.
+      i It is recommended to store the layout as x and y vertex attributes and not as a matrix graph attribute.
+
diff --git a/tests/testthat/test-plot.R b/tests/testthat/test-plot.R
index d444050058f..12f51bd2543 100644
--- a/tests/testthat/test-plot.R
+++ b/tests/testthat/test-plot.R
@@ -131,3 +131,11 @@ test_that("Edges stop at outside of rectangle node", {
 
   vdiffr::expect_doppelganger("rectangle-edges", rectangle_edges)
 })
+
+test_that("layout as graph attribute error works", {
+  g <- make_full_graph(10)
+  g$layout <- layout_in_circle(g)[1:5, ]
+  expect_snapshot(error = TRUE, {
+    plot(g)
+  })
+})