Fix `Array.slice()` rounding for `abs(step) != 1`

(cherry picked from commit 10f385fb792dc74ffb8be221fec88ba9ef7aaa25)

2 files changed, 22 insertions, 11 deletions

diff --git a/core/variant/array.cpp b/core/variant/array.cpp
index d156c35343..5215142dd3 100644
--- a/core/variant/array.cpp
+++ b/core/variant/array.cpp
@@ -466,7 +466,7 @@ Array Array::slice(int p_begin, int p_end, int p_step, bool p_deep) const {
 	ERR_FAIL_COND_V_MSG(p_step > 0 && begin > end, result, "Slice is positive, but bounds is decreasing.");
 	ERR_FAIL_COND_V_MSG(p_step < 0 && begin < end, result, "Slice is negative, but bounds is increasing.");
 
-	int result_size = (end - begin) / p_step;
+	int result_size = (end - begin) / p_step + (((end - begin) % p_step != 0) ? 1 : 0);
 	result.resize(result_size);
 
 	for (int src_idx = begin, dest_idx = 0; dest_idx < result_size; ++dest_idx) {
diff --git a/tests/core/variant/test_array.h b/tests/core/variant/test_array.h
index 04d5bb5107..ccb02ed5fa 100644
--- a/tests/core/variant/test_array.h
+++ b/tests/core/variant/test_array.h
@@ -253,6 +253,7 @@ TEST_CASE("[Array] slice()") {
 	array.push_back(2);
 	array.push_back(3);
 	array.push_back(4);
+	array.push_back(5);
 
 	Array slice0 = array.slice(0, 0);
 	CHECK(slice0.size() == 0);
@@ -263,42 +264,52 @@ TEST_CASE("[Array] slice()") {
 	CHECK(slice1[1] == Variant(2));
 
 	Array slice2 = array.slice(1, -1);
-	CHECK(slice2.size() == 3);
+	CHECK(slice2.size() == 4);
 	CHECK(slice2[0] == Variant(1));
 	CHECK(slice2[1] == Variant(2));
 	CHECK(slice2[2] == Variant(3));
+	CHECK(slice2[3] == Variant(4));
 
 	Array slice3 = array.slice(3);
-	CHECK(slice3.size() == 2);
+	CHECK(slice3.size() == 3);
 	CHECK(slice3[0] == Variant(3));
 	CHECK(slice3[1] == Variant(4));
+	CHECK(slice3[2] == Variant(5));
 
 	Array slice4 = array.slice(2, -2);
-	CHECK(slice4.size() == 1);
+	CHECK(slice4.size() == 2);
 	CHECK(slice4[0] == Variant(2));
+	CHECK(slice4[1] == Variant(3));
 
 	Array slice5 = array.slice(-2);
 	CHECK(slice5.size() == 2);
-	CHECK(slice5[0] == Variant(3));
-	CHECK(slice5[1] == Variant(4));
+	CHECK(slice5[0] == Variant(4));
+	CHECK(slice5[1] == Variant(5));
 
 	Array slice6 = array.slice(2, 42);
-	CHECK(slice6.size() == 3);
+	CHECK(slice6.size() == 4);
 	CHECK(slice6[0] == Variant(2));
 	CHECK(slice6[1] == Variant(3));
 	CHECK(slice6[2] == Variant(4));
+	CHECK(slice6[3] == Variant(5));
 
 	Array slice7 = array.slice(4, 0, -2);
 	CHECK(slice7.size() == 2);
 	CHECK(slice7[0] == Variant(4));
 	CHECK(slice7[1] == Variant(2));
 
-	ERR_PRINT_OFF;
-	Array slice8 = array.slice(4, 1);
-	CHECK(slice8.size() == 0);
+	Array slice8 = array.slice(5, 0, -2);
+	CHECK(slice8.size() == 3);
+	CHECK(slice8[0] == Variant(5));
+	CHECK(slice8[1] == Variant(3));
+	CHECK(slice8[2] == Variant(1));
 
-	Array slice9 = array.slice(3, -4);
+	ERR_PRINT_OFF;
+	Array slice9 = array.slice(4, 1);
 	CHECK(slice9.size() == 0);
+
+	Array slice10 = array.slice(3, -4);
+	CHECK(slice10.size() == 0);
 	ERR_PRINT_ON;
 }