Fixed the datarace surrounding the channel. This was done by moving the

channel close to the writer goroutine (as is idiomatic). readSheetFromFile
now returns an error to stop the writer routine from trying to read more
sheets if one contains an error (this will prevent goroutines from
leaking due to readers that stop reading on receiving an error).

lib.go

@@ -646,13 +646,15 @@ func readSheetViews(xSheetViews xlsxSheetViews) []SheetView {
 // into a Sheet struct.  This work can be done in parallel and so
 // readSheetsFromZipFile will spawn an instance of this function per
 // sheet and get the results back on the provided channel.
-func readSheetFromFile(sc chan *indexedSheet, index int, rsheet xlsxSheet, fi *File, sheetXMLMap map[string]string) {
+func readSheetFromFile(sc chan *indexedSheet, index int, rsheet xlsxSheet, fi *File, sheetXMLMap map[string]string) (errRes error) {
 	result := &indexedSheet{Index: index, Sheet: nil, Error: nil}
 	defer func() {
 		if e := recover(); e != nil {
+
 			switch e.(type) {
 			case error:
 				result.Error = e.(error)
+				errRes = e.(error)
 			default:
 				result.Error = errors.New("unexpected error")
 			}
@@ -665,7 +667,7 @@ func readSheetFromFile(sc chan *indexedSheet, index int, rsheet xlsxSheet, fi *F
 	if error != nil {
 		result.Error = error
 		sc <- result
-		return
+		return error
 	}
 	sheet := new(Sheet)
 	sheet.File = fi
@@ -680,6 +682,7 @@ func readSheetFromFile(sc chan *indexedSheet, index int, rsheet xlsxSheet, fi *F
 
 	result.Sheet = sheet
 	sc <- result
+	return nil
 }
 
 // readSheetsFromZipFile is an internal helper function that loops
@@ -719,12 +722,14 @@ func readSheetsFromZipFile(f *zip.File, file *File, sheetXMLMap map[string]strin
 	sheetsByName := make(map[string]*Sheet, sheetCount)
 	sheets := make([]*Sheet, sheetCount)
 	sheetChan := make(chan *indexedSheet, sheetCount)
-	defer close(sheetChan)
 
 	go func() {
+		defer close(sheetChan)
 		err = nil
 		for i, rawsheet := range workbookSheets {
-			readSheetFromFile(sheetChan, i, rawsheet, file, sheetXMLMap)
+			if err := readSheetFromFile(sheetChan, i, rawsheet, file, sheetXMLMap); err != nil {
+				return
+			}
 		}
 	}()