[R] Use NA_real_ to initialize handle (#1255)

R-package/R/lgb.Dataset.R

@@ -167,7 +167,7 @@ Dataset <- R6Class(
       if (!is.null(private$reference)) {
         ref_handle <- private$reference$.__enclos_env__$private$get_handle()
       }
-      handle <- 0.0
+      handle <- NA_real_
       
       # Not subsetting
       if (is.null(private$used_indices)) {

R-package/R/utils.R

@@ -7,7 +7,7 @@ lgb.is.Dataset <- function(x) {
 }
 
 lgb.is.null.handle <- function(x) {
-  is.null(x) || x == 0.0
+  is.null(x) || is.na(x)
 }
 
 lgb.encode.char <- function(arr, len) {

R-package/tests/testthat/test_dataset.R

@@ -26,6 +26,8 @@ test_that("lgb.Dataset: basic construction, saving, loading", {
 
 test_that("lgb.Dataset: getinfo & setinfo", {
   dtest <- lgb.Dataset(test_data)
+  dtest$construct()
+  
   setinfo(dtest, 'label', test_label)
   labels <- getinfo(dtest, 'label')
   expect_equal(test_label, getinfo(dtest, 'label'))
@@ -66,3 +68,17 @@ test_that("lgb.Dataset: nrow is correct for a very sparse matrix", {
   dtest <- lgb.Dataset(x)
   expect_equal(dim(dtest), dim(x))
 })
+
+test_that("lgb.Dataset: Dataset should be able to construct from matrix and return non-null handle", {
+  rawData <- matrix(runif(1000),ncol=10)
+  handle <- NA_real_
+  ref_handle <- NULL
+  handle <- lightgbm:::lgb.call("LGBM_DatasetCreateFromMat_R"
+                                , ret = handle
+                                , rawData
+                                , nrow(rawData)
+                                , ncol(rawData)
+                                , lightgbm:::lgb.params2str(params=list())
+                                , ref_handle)
+  expect_false(is.na(handle))
+})