From 75a7e642e03660290c7608532997541af751f249 Mon Sep 17 00:00:00 2001
From: ispyisail <shane.ringrose@gmail.com>
Date: Thu, 1 Oct 2026 15:21:51 +1300
Subject: [PATCH] Fix bugtracker #266: skip shapes with a nan coordinate in the
 element editor

A symbol with a "nan" or "inf" coordinate (bugtracker #266 had a line
with x1="nan" x2="nan") opened with that shape invisible and the view
off-centre. Moving the selection then snapped NaN through qRound() to
INT_MIN, and saving wrote width="-2147483630", breaking the symbol.

The folio already leaves such a shape out (ElementPictureFactory reads it
with QET::attributeIsAReal()). Do the same in the element editor, and
have --check-elements warn about it. Only geometry attributes are read,
so a text whose content is "inf" is not affected.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 sources/cli_export.cpp          | 13 +++++++++++++
 sources/editor/elementscene.cpp |  8 ++++++++
 sources/qet.cpp                 | 28 ++++++++++++++++++++++++++++
 sources/qet.h                   |  1 +
 4 files changed, 50 insertions(+)

diff --git a/sources/cli_export.cpp b/sources/cli_export.cpp
index 2927e6115..c8734cac8 100644
--- a/sources/cli_export.cpp
+++ b/sources/cli_export.cpp
@@ -529,6 +529,19 @@ int checkOneElement(const QString &path)
 		return 2;
 	}
 
+	// QET loads the element but leaves out a shape with a "nan" or "inf"
+	// coordinate, on the folio and in the element editor.
+	const QDomNodeList description = root.elementsByTagName("description");
+	for (QDomNode n = description.isEmpty() ? QDomNode()
+					  : description.at(0).firstChild() ;
+		 !n.isNull() ; n = n.nextSibling()) {
+		const QDomElement shape = n.toElement();
+		if (!shape.isNull() && QET::hasNonFiniteGeometry(shape)) {
+			out << "WARN  " << path << "  (<" << shape.tagName()
+				<< "> with a non-finite coordinate is not drawn)\n";
+			return 1;
+		}
+	}
 	// Negative dimensions are malformed but QET still loads them; surface as a
 	// warning rather than a failure so this agrees with QET's own loader.
 	if (w < 0 || h < 0) {
diff --git a/sources/editor/elementscene.cpp b/sources/editor/elementscene.cpp
index d5f0c6fa2..a9b8d85d2 100644
--- a/sources/editor/elementscene.cpp
+++ b/sources/editor/elementscene.cpp
@@ -1272,6 +1272,14 @@ ElementContent ElementScene::loadContent(const QDomDocument &xml_document)
 				CustomElementPart *cep = nullptr;
 				PartDynamicTextField *pdtf = nullptr;
 
+					//A shape with a "nan" or "inf" coordinate is not drawn
+					//on the folio either; loading it would only break the view
+				if (QET::hasNonFiniteGeometry(qde)) {
+					qWarning() << "Element editor: skipped a" << qde.tagName()
+							   << "with a non-finite coordinate";
+					continue;
+				}
+
 				if      (qde.tagName() == "line")       cep = new PartLine      (m_element_editor);
 				else if (qde.tagName() == "rect")       cep = new PartRectangle (m_element_editor);
 				else if (qde.tagName() == "ellipse")    cep = new PartEllipse   (m_element_editor);
diff --git a/sources/qet.cpp b/sources/qet.cpp
index 4e5db31d8..46f0bfb63 100644
--- a/sources/qet.cpp
+++ b/sources/qet.cpp
@@ -256,6 +256,34 @@ bool QET::attributeIsAReal(
 	return(true);
 }
 
+/**
+	@brief QET::hasNonFiniteGeometry
+	@param shape a shape of an element definition (<line>, <rect>, <text>...)
+	@return true if one of its coordinates or sizes is "nan" or "inf".
+	The folio does not draw such a shape (see attributeIsAReal()), and the
+	element editor cannot show or edit it.
+*/
+bool QET::hasNonFiniteGeometry(const QDomElement &shape)
+{
+	static const QStringList geometry {
+		"x", "y", "x1", "y1", "x2", "y2", "width", "height", "diameter",
+		"rx", "ry", "start", "angle", "rotation", "length1", "length2"};
+	static const QRegularExpression polygon_point("^[xy][0-9]+$");
+
+	const QDomNamedNodeMap attributes = shape.attributes();
+	for (int i = 0 ; i < attributes.count() ; ++i)
+	{
+		const QDomAttr attribute = attributes.item(i).toAttr();
+		if (!geometry.contains(attribute.name())
+			&& !polygon_point.match(attribute.name()).hasMatch())
+			continue;
+		bool ok;
+		const qreal value = attribute.value().toDouble(&ok);
+		if (ok && !std::isfinite(value)) return(true);
+	}
+	return(false);
+}
+
 /**
 	@brief QET::infoFlagIsTrue
 	@see the header comment for why this exists rather than a bare
diff --git a/sources/qet.h b/sources/qet.h
index 11438d2c2..6901446a0 100644
--- a/sources/qet.h
+++ b/sources/qet.h
@@ -162,6 +162,7 @@ namespace QET {
 	bool orthogonalProjection(const QPointF &, const QLineF &, QPointF * = nullptr);
 	bool attributeIsAnInteger(const QDomElement &, const QString& , int * = nullptr);
 	bool attributeIsAReal(const QDomElement &, const QString& , qreal * = nullptr);
+	bool hasNonFiniteGeometry(const QDomElement &);
 		/**
 			Whether an elementInformations flag (auto_num_locked,
 			potential_isolating, exclude_from_bom, ...) counts as "on".