From c7232af8ebe3e30d1ef11102c41e0e92fb148127 Mon Sep 17 00:00:00 2001
From: NiLuJe <ninuje@gmail.com>
Date: Fri, 18 Jun 2021 19:16:02 +0200
Subject: [PATCH] Statistics: Don't try to store a nil in a TEXT field

Fix #7867
---
 plugins/statistics.koplugin/main.lua | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/plugins/statistics.koplugin/main.lua b/plugins/statistics.koplugin/main.lua
index 9bb051513..230b3e629 100644
--- a/plugins/statistics.koplugin/main.lua
+++ b/plugins/statistics.koplugin/main.lua
@@ -72,9 +72,9 @@ local ReaderStatistics = Widget:extend{
     page_stat = {}, -- Dictionary, indexed by page (hash), contains a list (array) of { timestamp, duration } tuples.
     data = {
         title = "",
-        authors = "",
-        language = "",
-        series = "",
+        authors = "N/A",
+        language = "N/A",
+        series = "N/A",
         performance_in_pages = {},
         total_time_in_sec = 0,
         highlights = 0,
@@ -193,8 +193,17 @@ function ReaderStatistics:initData()
         self.data.title = self.document.file:match("^.+/(.+)$")
     end
     self.data.authors = book_properties.authors
+    if self.data.authors == nil or self.data.authors == "" then
+        self.data.authors = "N/A"
+    end
     self.data.language = book_properties.language
+    if self.data.language == nil or self.data.language == "" then
+        self.data.language = "N/A"
+    end
     self.data.series = book_properties.series
+    if self.data.series == nil or self.data.series == "" then
+        self.data.series = "N/A"
+    end
 
     self.data.pages = self.view.document:getPageCount()
     if not self.data.md5 then