From 49c220a63143dc313559176718e053b4d87707fa Mon Sep 17 00:00:00 2001
From: SebKrantz <sebastian.krantz@graduateinstitute.ch>
Date: Wed, 3 Dec 2025 20:57:58 -0500
Subject: [PATCH] Fixes #803.

---
 NEWS.md                                    |  2 ++
 src/pivot.c                                |  8 +++----
 tests/testthat/test-miscellaneous-issues.R | 25 ++++++++++++++++++++++
 3 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/NEWS.md b/NEWS.md
index d2ae99b9..ba93b3f8 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,7 @@
 # collapse 2.1.5.9000
 
+* Fixed bug in `pivot(..., how = "wider", FUN = "sum")` (using internal sum function) when columns to aggregate were integer typed. Thanks @ummel (#803). 
+
 * Faster installation from source thanks to the `#include <Rcpp/Lighter>` option in *Rcpp* which loads only part of the header files. Thanks @eddelbuettel for the hint. 
 
 # collapse 2.1.5
diff --git a/src/pivot.c b/src/pivot.c
index 591c4a59..d3510b5f 100644
--- a/src/pivot.c
+++ b/src/pivot.c
@@ -184,14 +184,14 @@ switch(aggfun) {
 #define AGGFUN_SWITCH_NUM(tdef, TYPEACC, NONMISSCHECK, ISMISS)                             \
 switch(aggfun) {                                                                           \
   case 4: { /* sum: no multithreading because possible race condition */                   \
-      for(int i = 0; i != l; ++i) if(NONMISSCHECK) TYPEACC(pout[pid[i]])[pix[i]-1] += pc[i]; \
+      for(int i = 0; i != l; ++i) if(NONMISSCHECK) DBL_DATAPTR(pout[pid[i]])[pix[i]-1] += pc[i]; \
   } break;                                                                                 \
   case 5: { /* mean: no multithreading because possible race condition */                  \
     int *restrict count = (int*)R_Calloc(nr*nc+1, int);                                      \
-    tdef *meani = TYPEACC(pout[1]);                                                        \
+    double *meani = DBL_DATAPTR(pout[1]);                                                        \
     for(int i = 0; i != l; ++i) {                                                          \
       if(NONMISSCHECK) {                                                                   \
-        meani = TYPEACC(pout[pid[i]])-1;                                                   \
+        meani = DBL_DATAPTR(pout[pid[i]])-1;                                                   \
         if(ISMISS(meani[pix[i]])) {                                                        \
           meani[pix[i]] = pc[i];                                                           \
           ++count[(pid[i]-1)*nr+pix[i]];                                                   \
@@ -247,7 +247,7 @@ SEXP pivot_wide(SEXP index, SEXP id, SEXP column, SEXP fill, SEXP Rnthreads, SEX
   if(aggfun < 3 || aggfun > 4) {
     SEXP fill_val;
     if(fill == R_NilValue || aggfun > 4) {
-      fill_val = tx == REALSXP ? ScalarReal(NA_REAL) : tx == INTSXP ? ScalarInteger(NA_INTEGER) :
+      fill_val = tx == REALSXP || aggfun == 5 ? ScalarReal(NA_REAL) : tx == INTSXP ? ScalarInteger(NA_INTEGER) :
       tx == LGLSXP ? ScalarLogical(NA_LOGICAL) : tx == STRSXP ? ScalarString(NA_STRING) :
       tx == CPLXSXP ? ScalarComplex(asComplex(ScalarReal(NA_REAL))) : tx == RAWSXP ? ScalarRaw(0) : R_NilValue;
     } else if(TYPEOF(fill) == tx) {
diff --git a/tests/testthat/test-miscellaneous-issues.R b/tests/testthat/test-miscellaneous-issues.R
index 9cdfab94..e388f52a 100644
--- a/tests/testthat/test-miscellaneous-issues.R
+++ b/tests/testthat/test-miscellaneous-issues.R
@@ -478,4 +478,29 @@ test_that("Misc bugs", {
 })
 
 
+test_that("Pivot with integers", { #803
+
+  iris_long <- pivot(iris, "Species")
+  iris_long$value <- round(iris_long$value)  # Double
+  iris_long$value_int = as.integer(iris_long$value)  # Integer
+
+  for (f in c("sum", "mean")) {
+  expect_equal(
+    pivot(
+      data = iris_long,
+      ids = "Species",
+      values = "value",
+      how = "wider",  # Pivoting to wide format
+      FUN = "sum"
+    ),
+    pivot(
+      data = iris_long,
+      ids = "Species",
+      values = "value_int",
+      how = "wider",  # Pivoting to wide format
+      FUN = "sum"
+    ))
+  }
+})
+
 options(warn = 1)