From a38a78f6d6bd319a916ca8de87527e6d62137ec3 Mon Sep 17 00:00:00 2001
From: Yorik van Havre <yorik@uncreated.net>
Date: Fri, 29 Apr 2016 23:00:11 -0300
Subject: [PATCH] Allow to enter empty values in PropertyFloatList and
 PropertyIntegerList - issue #2535

---
 src/Gui/Widgets.cpp                     | 45 +++++++++++++------------
 src/Gui/propertyeditor/PropertyItem.cpp |  5 ++-
 2 files changed, 27 insertions(+), 23 deletions(-)

diff --git a/src/Gui/Widgets.cpp b/src/Gui/Widgets.cpp
index 1dbc10d41..694a943e1 100644
--- a/src/Gui/Widgets.cpp
+++ b/src/Gui/Widgets.cpp
@@ -1151,32 +1151,33 @@ public:
         QStringList lines;
         if (edit) {
             QString inputText = edit->toPlainText();
-            lines = inputText.split(QString::fromLatin1("\n"));
+            if (!inputText.isEmpty()) // let pass empty input, regardless of the type, so user can void the value
+                lines = inputText.split(QString::fromLatin1("\n"));
         }
-
-        if (type == 1) { // floats
-            bool ok;
-            int line=1;
-            for (QStringList::iterator it = lines.begin(); it != lines.end(); ++it, ++line) {
-                it->toDouble(&ok);
-                if (!ok) {
-                    QMessageBox::critical(this, tr("Invalid input"), tr("Input in line %1 is not a number").arg(line));
-                    return;
+        if (!lines.isEmpty()) {
+            if (type == 1) { // floats
+                bool ok;
+                int line=1;
+                for (QStringList::iterator it = lines.begin(); it != lines.end(); ++it, ++line) {
+                    it->toDouble(&ok);
+                    if (!ok) {
+                        QMessageBox::critical(this, tr("Invalid input"), tr("Input in line %1 is not a number").arg(line));
+                        return;
+                    }
+                }
+            }
+            else if (type == 2) { // integers
+                bool ok;
+                int line=1;
+                for (QStringList::iterator it = lines.begin(); it != lines.end(); ++it, ++line) {
+                    it->toInt(&ok);
+                    if (!ok) {
+                        QMessageBox::critical(this, tr("Invalid input"), tr("Input in line %1 is not a number").arg(line));
+                        return;
+                    }
                 }
             }
         }
-        else if (type == 2) { // integers
-            bool ok;
-            int line=1;
-            for (QStringList::iterator it = lines.begin(); it != lines.end(); ++it, ++line) {
-                it->toInt(&ok);
-                if (!ok) {
-                    QMessageBox::critical(this, tr("Invalid input"), tr("Input in line %1 is not a number").arg(line));
-                    return;
-                }
-            }
-        }
-
         QDialog::accept();
     }
 };
diff --git a/src/Gui/propertyeditor/PropertyItem.cpp b/src/Gui/propertyeditor/PropertyItem.cpp
index 600f844aa..2207357b5 100644
--- a/src/Gui/propertyeditor/PropertyItem.cpp
+++ b/src/Gui/propertyeditor/PropertyItem.cpp
@@ -2091,7 +2091,6 @@ QVariant PropertyFloatListItem::toString(const QVariant& prop) const
         list.append(QLatin1String("..."));
     }
     QString text = QString::fromUtf8("[%1]").arg(list.join(QLatin1String(",")));
-
     return QVariant(text);
 }
 
@@ -2120,6 +2119,8 @@ void PropertyFloatListItem::setValue(const QVariant& value)
         str << *it << ",";
     }
     str << "]";
+    if (data == QString::fromUtf8("[,]"))
+        data = QString::fromUtf8("[]");
     setPropertyValue(data);
 }
 
@@ -2193,6 +2194,8 @@ void PropertyIntegerListItem::setValue(const QVariant& value)
         str << *it << ",";
     }
     str << "]";
+    if (data == QString::fromUtf8("[,]"))
+        data = QString::fromUtf8("[]");
     setPropertyValue(data);
 }