From 10b9414dc3f1cb573ee19bc03ebefac53b265ce9 Mon Sep 17 00:00:00 2001
From: toby <43851547+toppyy@users.noreply.github.com>
Date: Wed, 8 Jan 2025 19:24:35 +0200
Subject: [PATCH] floor sub-day precision date before casting to int

---
 src/types.cpp              |  2 +-
 tests/testthat/test-date.R | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 tests/testthat/test-date.R

diff --git a/src/types.cpp b/src/types.cpp
index b691bfd5b..8858d0a78 100644
--- a/src/types.cpp
+++ b/src/types.cpp
@@ -328,7 +328,7 @@ double RDoubleType::Convert(double val) {
 }
 
 date_t RDateType::Convert(double val) {
-	return date_t((int32_t)val);
+	return date_t((int32_t) std::floor(val));
 }
 
 timestamp_t RTimestampType::Convert(double val) {
diff --git a/tests/testthat/test-date.R b/tests/testthat/test-date.R
new file mode 100644
index 000000000..bb2bd8b79
--- /dev/null
+++ b/tests/testthat/test-date.R
@@ -0,0 +1,20 @@
+
+
+test_that("Conversion of sub-dates prior Posix origin is correct", {
+  con <- dbConnect(duckdb())
+  on.exit(dbDisconnect(con, shutdown = TRUE))
+
+  df <- data.frame(
+    d = as.Date(c(-1.1, -0.1, 0, 0.1, 1.1), origin = "1970-01-01")
+  )
+
+  duckdb_register(con, "df", df)
+
+  res <- sql("from df", con)
+
+  expect_identical(
+    as.character(df$d),
+    as.character(res$d)
+  )
+})
+