From 1a3ed93de4cbcc0fdc70eb8149516fb1eb1a960a Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Wed, 22 Aug 2018 13:30:17 +0530
Subject: [PATCH] ToC Editor: When generating ToCs using headings/xpath ignore
 duplicate entries at the same level that have the same text. Fixes #1735799
 [[Enhancement] Filter dupes in TOC
 editor](https://bugs.launchpad.net/calibre/+bug/1735799)

---
 src/calibre/ebooks/oeb/polish/toc.py | 13 +++++++++++++
 src/calibre/gui2/toc/main.py         |  1 +
 2 files changed, 14 insertions(+)

diff --git a/src/calibre/ebooks/oeb/polish/toc.py b/src/calibre/ebooks/oeb/polish/toc.py
index 5546481892..b3c8ce3cbe 100644
--- a/src/calibre/ebooks/oeb/polish/toc.py
+++ b/src/calibre/ebooks/oeb/polish/toc.py
@@ -78,6 +78,19 @@ class TOC(object):
             for gc in child.iterdescendants():
                 yield gc
 
+    def remove_duplicates(self, only_text=True):
+        seen = set()
+        remove = []
+        for child in self:
+            key = child.title if only_text else (child.title, child.dest, (child.frag or None))
+            if key in seen:
+                remove.append(child)
+            else:
+                seen.add(key)
+                child.remove_duplicates()
+        for child in remove:
+            self.remove(child)
+
     @property
     def depth(self):
         """The maximum depth of the navigation tree rooted at this node."""
diff --git a/src/calibre/gui2/toc/main.py b/src/calibre/gui2/toc/main.py
index ace86330ba..b9ae81fecb 100644
--- a/src/calibre/gui2/toc/main.py
+++ b/src/calibre/gui2/toc/main.py
@@ -933,6 +933,7 @@ class TOCView(QWidget):  # {{{
         if len(toc) == 0:
             return error_dialog(self, _('No items found'),
                 _('No items were found that could be added to the Table of Contents.'), show=True)
+        toc.remove_duplicates()
         self.insert_toc_fragment(toc)
 
     def create_from_links(self):