From d7f7ddfc1802cf11d6c889ef3ee0712fb7af8da4 Mon Sep 17 00:00:00 2001
From: Richard Kimberly Heck <rikiheck@lyx.org>
Date: Mon, 27 May 2019 00:06:10 -0400
Subject: [PATCH] Fix crash reported by Kornel.

See https://marc.info/?l=lyx-devel&m=155879185229073&w=2.

The problem is that, after saving the document and reloading, the
TOC is corrupted, more or less, when we run through updateBuffer.
So we reset it first.
---
 src/Buffer.cpp     |  4 ++++
 src/TocBackend.cpp | 21 ++++++++++++++-------
 src/TocBackend.h   |  2 ++
 3 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/src/Buffer.cpp b/src/Buffer.cpp
index 6665a731e1..848f1f46e3 100644
--- a/src/Buffer.cpp
+++ b/src/Buffer.cpp
@@ -4980,6 +4980,10 @@ void Buffer::updateBuffer(UpdateScope scope, UpdateType utype) const
 	setChangesPresent(false);
 
 	Buffer & cbuf = const_cast<Buffer &>(*this);
+	// if we are reloading, then we could have a dangling TOC,
+	// in effect. so we need to go ahead and reset, even though
+	// we will do so again when we rebuild the TOC later.
+	cbuf.tocBackend().reset();
 
 	// do the real work
 	ParIterator parit = cbuf.par_iterator_begin();
diff --git a/src/TocBackend.cpp b/src/TocBackend.cpp
index a253d57ca3..65f96bae89 100644
--- a/src/TocBackend.cpp
+++ b/src/TocBackend.cpp
@@ -204,17 +204,24 @@ bool TocBackend::updateItem(DocIterator const & dit_in)
 }
 
 
-void TocBackend::update(bool output_active, UpdateType utype)
+void TocBackend::reset()
 {
-	for (TocList::iterator it = tocs_.begin(); it != tocs_.end(); ++it)
-		it->second->clear();
+	for (auto const & t: tocs_)
+		t.second->clear();
 	tocs_.clear();
 	builders_.clear();
 	resetOutlinerNames();
-	if (!buffer_->isInternal()) {
-		DocIterator dit;
-		buffer_->inset().addToToc(dit, output_active, utype, *this);
-	}
+}
+
+
+void TocBackend::update(bool output_active, UpdateType utype)
+{
+	reset();
+	if (buffer_->isInternal())
+		return;
+
+	DocIterator dit;
+	buffer_->inset().addToToc(dit, output_active, utype, *this);
 }
 
 
diff --git a/src/TocBackend.h b/src/TocBackend.h
index a38a972834..0e123ee5f0 100644
--- a/src/TocBackend.h
+++ b/src/TocBackend.h
@@ -113,6 +113,8 @@ public:
 	void setBuffer(Buffer const * buffer) { buffer_ = buffer; }
 	///
 	void update(bool output_active, UpdateType utype);
+	///
+	void reset();
 	/// \return true if the item was updated.
 	bool updateItem(DocIterator const & pit);
 	///
-- 
2.39.5