Joining potentials: agreeing ones leave nothing to choose

ConductorCreator asked which potential's properties to keep whenever a
new wire joined two potentials, even when they agreed in every
property; headless (scripting, qet MCP) such a wire was refused. Only
distinct properties are offered now, and with one left the wire takes it.

A potential's properties seen through one of a cable's cores carried
the core with them -- cable, cable uuid, core slot, and the core label
CableManager writes as text -- so a new wire claimed to be that core.
They are cleared; the text is left to the formula.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

misc/qet-mcp/test_qet_mcp.py

@@ -4534,12 +4534,28 @@ class Integration(unittest.TestCase):
               for i in range(4)],
             {"op": "add_conductor", "folio": "$f", "from": "$e0", "from_terminal": 0, "to": "$e1", "to_terminal": 0},
             {"op": "add_conductor", "folio": "$f", "from": "$e2", "from_terminal": 0, "to": "$e3", "to_terminal": 0},
+            {"op": "set_conductor", "folio": "$f", "element": "$e2", "terminal": 0, "property": "num", "value": "W2"},
             {"op": "add_conductor", "folio": "$f", "from": "$e0", "from_terminal": 0, "to": "$e2", "to_terminal": 0},
         ], self.sb.p("conflict.qet"), elements_dir=ELEMENTS, timeout=60)
         self.assertFalse(r.get("timed_out"), "the call hung on a modal dialog")
         self.assertFalse(r["ok"])
         self.assertEqual(r["operations"][-1]["result"], False)
 
+    def test_joining_two_agreeing_potentials_asks_nothing(self):
+        """Two potentials with the same properties leave nothing to choose:
+        the wire joining them is drawn, headless as well."""
+        base = self.sb.new()
+        r = self.ok(self.sb.edit(base, [
+            {"op": "add_folio", "id": "f"},
+            *[{"op": "add_element", "id": f"e{i}", "folio": "$f", "path": COIL, "x": 100 + i * 200, "y": 100}
+              for i in range(4)],
+            {"op": "add_conductor", "folio": "$f", "from": "$e0", "from_terminal": 0, "to": "$e1", "to_terminal": 0},
+            {"op": "set_conductor", "folio": "$f", "element": "$e0", "terminal": 0, "property": "num", "value": "N"},
+            {"op": "add_conductor", "folio": "$f", "from": "$e2", "from_terminal": 0, "to": "$e3", "to_terminal": 0},
+            {"op": "set_conductor", "folio": "$f", "element": "$e2", "terminal": 0, "property": "num", "value": "N"},
+            {"op": "add_conductor", "folio": "$f", "from": "$e0", "from_terminal": 0, "to": "$e2", "to_terminal": 0}]))
+        self.assertEqual([c["num"] for c in m.tool_conductors(r["output"])["conductors"]], ["N"] * 3)
+
     # ---- edit: conductor properties, potentials ----
 
     def test_conductor_property_applies_to_the_whole_potential(self):

sources/utils/conductorcreator.cpp

@@ -128,7 +128,49 @@ bool ConductorCreator::needsPotentialChoice(const QList<Terminal *> &terminals_l
 	if (terminals_list.size() <= 1) {
 		return false;
 	}
-	return existingPotential(terminals_list).size() >= 2;
+	return distinctProperties(existingPotential(terminals_list)).size() >= 2;
+}
+
+/**
+	@brief ConductorCreator::inheritedProperties
+	The properties a new wire takes from @p conductor's potential. A
+	cable's core names the cable and the core in m_cable, m_cable_uuid,
+	m_cable_slot and, written by CableManager, in its text (15W1:BN): none
+	of that belongs to a new wire, which is in no cable yet. The text is
+	then left to the formula.
+	@param conductor : a conductor of the potential
+	@return the properties for a new conductor of that potential
+*/
+ConductorProperties ConductorCreator::inheritedProperties(const Conductor *conductor)
+{
+	ConductorProperties properties = conductor->properties();
+	if (!properties.m_cable_uuid.isNull())
+	{
+		properties.m_cable.clear();
+		properties.m_cable_uuid = QUuid();
+		properties.m_cable_slot = -1;
+		properties.text.clear();
+	}
+	return properties;
+}
+
+/**
+	@brief ConductorCreator::distinctProperties
+	@param potentials : one conductor of each potential (existingPotential())
+	@return the properties a new wire could inherit from them, each once:
+	two potentials that agree leave nothing to choose
+*/
+QList<ConductorProperties> ConductorCreator::distinctProperties(const QList<Conductor *> &potentials)
+{
+	QList<ConductorProperties> list;
+	for (const Conductor *c : potentials)
+	{
+		const ConductorProperties properties = inheritedProperties(c);
+		if (!list.contains(properties)) {
+			list.append(properties);
+		}
+	}
+	return list;
 }
 
 /**
@@ -146,28 +188,24 @@ bool ConductorCreator::setUpPropertieToUse()
 		//we get one of them
 	if (!potentials.isEmpty())
 	{
-		if (potentials.size() >= 2)
+		const QList<ConductorProperties> cp_list = distinctProperties(potentials);
+		if (cp_list.size() >= 2)
 		{
-			QList <ConductorProperties> cp_list;
-			for(Conductor *c : potentials) {
-				cp_list.append(c->properties());
-			}
-
 			bool cancelled = false;
 			m_properties = PotentialSelectorDialog::chosenProperties(cp_list, nullptr, &cancelled);
 			if (cancelled) {
 				return false;
 			}
-			for (Conductor *c : potentials) {
-				if (c->properties() == m_properties) {
-					m_sequential_number = c->sequenceNum();
-				}
-			}
 		}
-		else if (potentials.size() == 1)
+		else
 		{
-			m_properties = potentials.first()->properties();
-			m_sequential_number = potentials.first()->sequenceNum();
+			m_properties = cp_list.first();
+		}
+		for (Conductor *c : potentials) {
+			if (inheritedProperties(c) == m_properties) {
+				m_sequential_number = c->sequenceNum();
+				break;
+			}
 		}
 		return true;
 	}

sources/utils/conductorcreator.h

@@ -42,6 +42,8 @@ class ConductorCreator
 
 	private:
 		static QList<Conductor *> existingPotential(const QList<Terminal *> &terminals_list);
+		static ConductorProperties inheritedProperties(const Conductor *conductor);
+		static QList<ConductorProperties> distinctProperties(const QList<Conductor *> &potentials);
 		bool setUpPropertieToUse();
 		Terminal *hubTerminal();
 		QList<QPair<Terminal *, Terminal *>> terminalPairs(bool chain);