Merge pull request tidyverse#2637 from lionel-/fix-summarised-symbols

Fix hybrid handling of summarised symbols
patopiedra · Apr 12, 2017 · 22504ec · 22504ec
2 parents 832b1cb + b66864b
commit 22504ec
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Showing 2 changed files with 12 additions and 2 deletions.
diff --git a/src/hybrid.cpp b/src/hybrid.cpp
@@ -105,8 +105,13 @@ class VariableResult : public Result {
   VariableResult(const ILazySubsets& subsets_, const SymbolString& name_) : subsets(subsets_), name(name_)  {}
 
   SEXP process(const GroupedDataFrame& gdf) {
-    check_length(gdf.max_group_size(), 1, "a summary value", name);
-    return process(*gdf.group_begin());
+    if (subsets.is_summary(name)) {
+      // No need to check length since the summary has already been checked
+      return subsets.get_variable(name);
+    } else {
+      check_length(gdf.max_group_size(), 1, "a summary value", name);
+      return process(*gdf.group_begin());
+    }
   }
 
   SEXP process(const RowwiseDataFrame&) {

diff --git a/tests/testthat/test-summarise.r b/tests/testthat/test-summarise.r
@@ -947,3 +947,8 @@ test_that("proper handling of NA factors (#2588)", {
   ret <- df %>% group_by(x) %>% summarise(y = y[1])
   expect_identical(as.character(ret$y), c(NA, NA, "3"))
 })
+
+test_that("can refer to previously summarised symbols", {
+  expect_identical(summarise(group_by(mtcars, cyl), x = 1, z = x)[2:3], tibble(x = c(1, 1, 1), z = x))
+  expect_identical(summarise(group_by(mtcars, cyl), x = n(), z = x)[2:3], tibble(x = c(11L, 7L, 14L), z = x))
+})