avoid rel(0) margins, fix #6536

Author: teunbrand

R/theme-defaults.R

@@ -220,7 +220,7 @@ theme_grey <- function(base_size = 11, base_family = "",
     legend.direction =   NULL,
     legend.justification = "center",
     legend.box =         NULL,
-    legend.box.margin =  rel(0),
+    legend.box.margin =  margin_auto(0),
     legend.box.background = element_blank(),
     legend.box.spacing = rel(2),
 
@@ -562,8 +562,8 @@ theme_void <- function(base_size = 11, base_family = "",
     legend.text =        element_text(size = rel(0.8)),
     legend.title =       element_text(hjust = 0),
     legend.key.spacing = rel(1),
-    legend.margin =      rel(0),
-    legend.box.margin =  rel(0),
+    legend.margin =      margin_auto(0),
+    legend.box.margin =  margin_auto(0),
     legend.box.spacing = unit(0.2, "cm"),
     legend.ticks.length = rel(0.2),
     legend.background =  element_blank(),
@@ -578,7 +578,7 @@ theme_void <- function(base_size = 11, base_family = "",
     panel.spacing =      NULL,
     panel.background =   element_blank(),
     panel.border =       element_blank(),
-    plot.margin =        rel(0),
+    plot.margin =        margin_auto(0),
     plot.title =         element_text(
                            size = rel(1.2),
                            hjust = 0, vjust = 1,

R/theme.R

@@ -916,7 +916,7 @@ S7::method(merge_element, list(element, S7::class_any)) <-
 
 S7::method(merge_element, list(margin, S7::class_any)) <-
   function(new, old, ...) {
-    if (anyNA(new)) {
+    if (anyNA(new) && is_margin(old)) {
       new[is.na(new)] <- old[is.na(new)]
     }
     new