Keep the terminal number out of the element properties

The properties window builds a row for every element info key, so it
also offered an editable "Terminal number" row -- both for one element
and for several at once. The number is not a property of the element
but derived from its label: typing there stored a value nothing reads,
and the export has no column for it either (previous commit).

Both windows skip the key now, the way they skip exclude_from_bom.
The key itself stays an element info key, so the element editor keeps
offering %{terminal_number} as a text variable.

The test builds both windows for a terminal of the fixture and looks
at the rows they offer.

sources/ui/elementinfowidget.cpp

@@ -313,6 +313,13 @@ void ElementInfoWidget::buildInterface()
 		//line that currentInfo() then fills with "true"/"false".
 	keys.removeAll(QStringLiteral("exclude_from_bom"));
 
+		//The terminal number is not a property of the element: it is
+		//derived from its label, so an edit row here would store a value
+		//nothing reads -- and the nomenclature query has no such column,
+		//which is why the export does not offer it either. The number
+		//stays a text variable (%{terminal_number}) of the element editor.
+	keys.removeAll(QETInformation::ELMT_TERMINAL_NUMBER);
+
 	for (auto str : keys)
 	{
 		ElementInfoPartWidget *eipw = new ElementInfoPartWidget(str, QETInformation::translatedInfoKey(str), this);

sources/ui/multielementinfowidget.cpp

@@ -496,6 +496,9 @@ void MultiElementInfoWidget::buildInterface()
 	QStringList keys = QETInformation::elementInfoKeys();
 		//It has its own check box above, see ElementInfoWidget::buildInterface
 	keys.removeAll(EXCLUDE_FROM_BOM);
+		//Not an editable property but derived from the label, see
+		//ElementInfoWidget::buildInterface
+	keys.removeAll(QETInformation::ELMT_TERMINAL_NUMBER);
 
 	int line = 0;
 	for (const QString &key : std::as_const(keys))

tests/qttest/tst_terminallabeldisplay.cpp

@@ -21,6 +21,10 @@
 #include "TerminalStrip/terminalstrip.h"
 #include "dataBase/ui/elementquerywidget.h"
 #include "diagram.h"
+#include "ui/elementinfopartwidget.h"
+#include "ui/elementinfowidget.h"
+#include "ui/multielementinfowidget.h"
+#include <QLabel>
 #include <QListWidget>
 #include "properties/elementdata.h"
 #include "qetgraphicsitem/dynamicelementtextitem.h"
@@ -440,6 +444,43 @@ private slots:
 		QCOMPARE(QETInformation::elementInfoToVar(QETInformation::ELMT_TERMINAL_NUMBER),
 				 QStringLiteral("%{terminal_number}"));
 	}
+
+	//The properties of a terminal have no row for its number: the number
+	//is derived from the label, so a row there would offer an edit which
+	//stores a value nothing reads -- the export has no column for it, and
+	//the drawing takes the number from the label
+	void propertiesHaveNoRowForTheTerminalNumber()
+	{
+		const QString fixture = QFINDTESTDATA("fixtures/every_feature.qet");
+		QETProject project(fixture);
+		QCOMPARE(project.state(), QETProject::Ok);
+
+		Element *element = terminalWithLabel(project, QStringLiteral("X1:1"));
+		QVERIFY(element);
+
+			//The properties of one element...
+		ElementInfoWidget one(element);
+		QStringList one_rows;
+		const QList<ElementInfoPartWidget *> parts = one.findChildren<ElementInfoPartWidget *>();
+		for (const ElementInfoPartWidget *part : parts)
+			one_rows << part->key();
+		QVERIFY2(one_rows.contains(QETInformation::ELMT_LABEL),
+				 "The other properties are still offered");
+		QVERIFY2(!one_rows.contains(QETInformation::ELMT_TERMINAL_NUMBER),
+				 "The terminal number is no property of the element");
+
+			//...and the properties of several elements at once
+		MultiElementInfoWidget many({element});
+		QStringList rows;
+		const QList<QLabel *> labels = many.findChildren<QLabel *>();
+		for (const QLabel *label : labels)
+			rows << label->text();
+		QVERIFY2(rows.contains(QETInformation::translatedInfoKey(QETInformation::ELMT_LABEL)),
+				 "The other properties are still offered");
+		QVERIFY2(!rows.contains(
+					 QETInformation::translatedInfoKey(QETInformation::ELMT_TERMINAL_NUMBER)),
+				 "The terminal number is no property of the element");
+	}
 };
 
 QET_APP_TEST_MAIN(tst_terminallabeldisplay)