Fix bug #13017.

The problem is caused by removing temporary aux, etc, files while
we are in the process of exporting. As Jürgen suggested, we really
do not need to remove these files until we are preparing to export:
They are not used internally. So now we just schedule the removal
and do it then.

src/Buffer.cpp

@@ -2444,7 +2444,7 @@ void Buffer::invalidateBibinfoCache() const
 {
 	d->bibinfo_cache_valid_ = false;
 	d->cite_labels_valid_ = false;
-	removeBiblioTempFiles();
+	scheduleBiblioTempRemoval();
 	// also invalidate the cache for the parent buffer
 	Buffer const * const pbuf = d->parent();
 	if (pbuf)
@@ -2702,6 +2702,7 @@ void Buffer::removeBiblioTempFiles() const
 	Buffer const * const pbuf = parent();
 	if (pbuf)
 		pbuf->removeBiblioTempFiles();
+	removeBiblioTemps = false;
 }
 
 
@@ -4475,6 +4476,8 @@ void Buffer::setMathFlavor(OutputParams & op) const
 Buffer::ExportStatus Buffer::doExport(string const & target, bool put_in_tempdir,
 	bool includeall, string & result_file) const
 {
+	if (removeBiblioTemps)
+		removeBiblioTempFiles();
 	LYXERR(Debug::FILES, "target=" << target);
 	OutputParams runparams(&params().encoding());
 	string format = target;

src/Buffer.h

@@ -538,9 +538,6 @@ public:
 	/// dereferenced label name
 	void getLabelList(std::vector<std::tuple<docstring, docstring, docstring>> &) const;
 
-	/// This removes the .aux and .bbl files from the temp dir.
-	void removeBiblioTempFiles() const;
-
 	///
 	void changeLanguage(Language const * from, Language const * to);
 
@@ -704,6 +701,8 @@ private:
 	///
 	ExportStatus doExport(std::string const & target, bool put_in_tempdir,
 		std::string & result_file) const;
+	/// This removes the .aux and .bbl files from the temp dir.
+	void removeBiblioTempFiles() const;
 	/// target is a format name optionally followed by a space
 	/// and a destination file-name
 	ExportStatus doExport(std::string const & target, bool put_in_tempdir,
@@ -806,18 +805,20 @@ public:
 	/// of loaded child documents).
 	docstring_list const &
 		getBibfiles(UpdateScope scope = UpdateMaster) const;
-
+	///
+	void scheduleBiblioTempRemoval() const { removeBiblioTemps = true; }
 	/// routines for dealing with possible self-inclusion
 	void pushIncludedBuffer(Buffer const * buf) const;
 	void popIncludedBuffer() const;
 	bool isBufferIncluded(Buffer const * buf) const;
 private:
 	void clearIncludeList() const;
-
-private:
+	///
 	friend class MarkAsExporting;
 	/// mark the buffer as busy exporting something, or not
 	void setExportStatus(bool e) const;
+	///
+	mutable bool removeBiblioTemps = false;
 
 	///
 	References & getReferenceCache(docstring const & label);

src/frontends/qt/GuiView.cpp

@@ -527,6 +527,7 @@ public:
 	string last_export_format;
 	string processing_format;
 
+	// Buffers that are being exported
 	static QSet<Buffer const *> busyBuffers;
 
 	unsigned int smallIconSize;

src/insets/InsetCitation.cpp

@@ -50,7 +50,7 @@ namespace lyx {
 InsetCitation::InsetCitation(Buffer * buf, InsetCommandParams const & p)
 	: InsetCommand(buf, p)
 {
-	buffer().removeBiblioTempFiles();
+	buffer().scheduleBiblioTempRemoval();
 	cleanKeys();
 }
 
@@ -61,7 +61,7 @@ InsetCitation::~InsetCitation()
 		/* We do not use buffer() because Coverity believes that this
 		 * may throw an exception. Actually this code path is not
 		 * taken when buffer_ == 0 */
-		buffer_->removeBiblioTempFiles();
+		buffer_->scheduleBiblioTempRemoval();
 }
 
 
@@ -142,7 +142,7 @@ void InsetCitation::doDispatch(Cursor & cur, FuncRequest & cmd)
 		openCitation();
 		break;
 	case LFUN_INSET_MODIFY: {
-		buffer().removeBiblioTempFiles();
+		buffer().scheduleBiblioTempRemoval();
 		cache.recalculate = true;
 		if (cmd.getArg(0) == "toggleparam") {
 			string cmdname = getCmdName();