This closes #1384, fix segmentation fault in `formattedValue` (#1385)

- Add nil pointer guard in cell format
- Add tests to verify the nil checks in formattedValue

Co-authored-by: Zach Clark <zachmclark@gmail.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/cell.go b/cell.go
index eb60441..ebf4681 100644
--- a/cell.go
+++ b/cell.go
@@ -1292,6 +1292,9 @@ func (f *File) formattedValue(s int, v string, raw bool) string {
 		return v
 	}
 	styleSheet := f.stylesReader()
+	if styleSheet.CellXfs == nil {
+		return v
+	}
 	if s >= len(styleSheet.CellXfs.Xf) {
 		return v
 	}
@@ -1306,7 +1309,7 @@ func (f *File) formattedValue(s int, v string, raw bool) string {
 	if ok := builtInNumFmtFunc[numFmtID]; ok != nil {
 		return ok(v, builtInNumFmt[numFmtID], date1904)
 	}
-	if styleSheet == nil || styleSheet.NumFmts == nil {
+	if styleSheet.NumFmts == nil {
 		return v
 	}
 	for _, xlsxFmt := range styleSheet.NumFmts.NumFmt {