feat: Stop accepting setting layout as a graph attribute if it is a matrix

Author: krlmlr

R/attributes.R

@@ -336,6 +336,21 @@ graph_attr <- function(graph, name) {
 set_graph_attr <- function(graph, name, value) {
   ensure_igraph(graph)
 
+  # Code that accesses g$layout can stay for now, revisit in 2029.
+  if (name == "layout" && is.matrix(value)) {
+    if (ncol(value) == 2) {
+      lifecycle::deprecate_stop("2.0.3", "set_graph_attr(layout = 'matrix(...)')", details = "Using a matrix for the `layout` attribute is deprecated. Use vertex attributes `x` and `y` instead.")
+      value <- list(x = value[, 1], y = value[, 2])
+    } else if (ncol(value) == 3) {
+      lifecycle::deprecate_stop("2.0.3", "set_graph_attr(layout = 'matrix(...)')", details = "Using a matrix for the `layout` attribute is deprecated. Use vertex attributes `x`, `y` and `z` instead.")
+      value <- list(x = value[, 1], y = value[, 2], z = value[, 3])
+    } else {
+      lifecycle::deprecate_stop("2.0.3", "set_graph_attr(layout = 'matrix(...)')", details = "Using a matrix for the `layout` attribute is defunct. Use vertex attributes `x`, `y` and `z` instead.")
+    }
+
+    return(set_vertex_attr(graph, name, value))
+  }
+
   .Call(R_igraph_mybracket3_set, graph, igraph_t_idx_attr, igraph_attr_idx_graph, name, value)
 }