[write] do not try to apply a cell style to data frames with zero rows. fixes #985

NEWS.md

@@ -5,6 +5,12 @@
 * Helper to read sensitivity labels from files and apply them to workbooks. 
 [983](https://github.com/JanMarvin/openxlsx2/pull/983)
 
+## Fixes
+
+* Allow writing data frames with zero rows. [987](https://github.com/JanMarvin/openxlsx2/pull/987)
+
+
+***************************************************************************
 
 # openxlsx2 1.5
 

R/write.R

@@ -277,6 +277,8 @@ write_data2 <- function(
       dc <- c(c("_rowNames_" = openxlsx2_celltype[["character"]]), dc)
     }
 
+    if (nrow(data) == 0) applyCellStyle <- FALSE
+
     # add colnames
     if (colNames) {
       # its quicker to convert data to character and append the colnames

inst/WORDLIST

@@ -24,6 +24,7 @@ JOHAB
 Kaku
 LastModifiedBy
 Libreoffice
+MIP
 OEM
 ORCID
 Openoffice
@@ -34,6 +35,7 @@ RGBA
 RedToBlack
 RowStripe
 RowSubheading
+Rprofile
 SHIFTJIS
 STDEV
 STDEVP
@@ -159,6 +161,7 @@ mediumDashDot
 mediumDashed
 mediumGray
 minAxisType
+mips
 mmm
 mmss
 mschart
@@ -203,6 +206,7 @@ queryTables
 reimported
 rels
 rgb
+richData
 rightToLeft
 rowColHeaders
 rowNames

tests/testthat/test-write.R

@@ -959,3 +959,30 @@ test_that("dims size warnings work", {
   )
 
 })
+
+test_that("writing zero row data frames works", {
+
+  # write an empty data frame
+  dat <- data.frame()
+  expect_silent(wb <- wb_workbook()$add_worksheet()$add_data(x = dat))
+
+  exp <- NULL
+  expect_message(got <- wb_to_df(wb), "sheet found, but contains no data")
+  expect_equal(exp, got)
+
+  # write a data frame containing an empty date vector
+  dat <- data.frame(date = base::as.Date(NULL))
+  expect_silent(wb <- wb_workbook()$add_worksheet()$add_data(x = dat))
+
+  exp <- "date"
+  got <- names(wb_to_df(wb))
+  expect_equal(exp, got)
+
+  # try the same with write_xlsx()
+  expect_silent(wb <- write_xlsx(x = dat))
+
+  exp <- "date"
+  got <- names(wb_to_df(wb))
+  expect_equal(exp, got)
+
+})