Throw error with illigal combination of space in facet_grid and aspect.ratio in theme (#4432)

Author: thomasp85

NEWS.md

@@ -1,11 +1,14 @@
 # ggplot2 (development version)
 
+* Using `theme(aspect.ratio = ...)` together with free space in `facet_grid()`
+  now crrectly throws an error (@thomasp85, #3834)
+  
 * Fix a bug in `stat_summary_bin()` where one more than the requested number of
   bins would be created (@thomasp85, #3824)
 
 * Fix a bug in `geom_abline()` that resulted in `intercept` not being subjected
   to the transformation of the y scale (@thomasp85, #3741)
-
+  
 * Fix bug in `guide_coloursteps()` that would repeat the terminal bins if the
   breaks coincided with the limits of the scale (@thomasp85, #4019)
 

R/facet-grid-.r

@@ -309,6 +309,9 @@ FacetGrid <- ggproto("FacetGrid", Facet,
     strips <- render_strips(col_vars, row_vars, params$labeller, theme)
 
     aspect_ratio <- theme$aspect.ratio
+    if (!is.null(aspect_ratio) && (params$space_free$x || params$space_free$y)) {
+      abort("Free scales cannot be mixed with a fixed aspect ratio")
+    }
     if (is.null(aspect_ratio) && !params$free$x && !params$free$y) {
       aspect_ratio <- coord$aspect(ranges[[1]])
     }