dont try to merge identical bar traces, fixes #250

Author: cpsievert

R/ggplotly.R

@@ -851,7 +851,7 @@ gg2list <- function(p) {
         tr.attr <- tr[[must.be.equal]]
         criteria[[must.be.equal]] <- isTRUE(all.equal(other.attr, tr.attr))
       }
-      if(all(criteria)){
+      if(all(criteria) && tr$type != "bar"){
         can.merge[[other.i]] <- TRUE
       }
     }

tests/testthat/test-ggplot-stack.R

@@ -21,3 +21,19 @@ test_that("y value is non-cumulative in stacked bar charts", {
   expect_equal(L$data[[2]]$y[2], instructors$number[5])
   expect_equal(L$data[[3]]$y[2], instructors$number[6])
 })
+
+testd <- data.frame(
+  group1 = rep(1:3, each = 3),
+  group2 = LETTERS[1:3],
+  # We have two 0.2 within each group.
+  count = c(0.2, 0.2, 0.6)
+) 
+
+test_that("can stack identical traces", {
+  p1 <- ggplot(testd, aes(x = factor(group1), y = count, 
+                          fill = factor(group2))) + 
+    geom_bar(stat = 'identity', width = 1, position = "stack")
+  L <- save_outputs(p1, "stack-identical")
+  expect_equal(length(L$data), 3)
+})
+