From 301fcc2ab7d6284a1c86f2c4d2b05e05004d258c Mon Sep 17 00:00:00 2001
From: Eivind Kvedalen <eivind@kvedalen.name>
Date: Fri, 15 Jan 2016 23:37:41 +0100
Subject: [PATCH] Spreadsheet: Issue #2402: Don't allow duplicate aliases.

---
 src/Mod/Spreadsheet/App/Sheet.cpp      |  9 ++++++++-
 src/Mod/Spreadsheet/App/SheetPyImp.cpp | 13 ++++++++++---
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/src/Mod/Spreadsheet/App/Sheet.cpp b/src/Mod/Spreadsheet/App/Sheet.cpp
index b9b3931dd..db9ac92fe 100644
--- a/src/Mod/Spreadsheet/App/Sheet.cpp
+++ b/src/Mod/Spreadsheet/App/Sheet.cpp
@@ -1130,7 +1130,14 @@ void Sheet::setComputedUnit(CellAddress address, const Base::Unit &unit)
 
 void Sheet::setAlias(CellAddress address, const std::string &alias)
 {
-    cells.setAlias(address, alias);
+    const Cell * cell = cells.getValueFromAlias(alias);
+
+    if (cell != 0)
+        throw Base::Exception("Alias already defined.");
+    else
+        cells.setAlias(address, alias);
+}
+
 /**
  * @brief Get cell given an alias string
  * @param alias Alias for cell
diff --git a/src/Mod/Spreadsheet/App/SheetPyImp.cpp b/src/Mod/Spreadsheet/App/SheetPyImp.cpp
index aad6887be..f35296845 100644
--- a/src/Mod/Spreadsheet/App/SheetPyImp.cpp
+++ b/src/Mod/Spreadsheet/App/SheetPyImp.cpp
@@ -441,14 +441,21 @@ PyObject* SheetPy::setAlias(PyObject *args)
 {
     CellAddress address;
     const char * strAddress;
-    const char * value;
+    PyObject * value;
 
-    if (!PyArg_ParseTuple(args, "ss:setAlias", &strAddress, &value))
+    if (!PyArg_ParseTuple(args, "sO:setAlias", &strAddress, &value))
         return 0;
 
     try {
         address = stringToAddress(strAddress);
-        getSheetPtr()->setAlias(address, value);
+
+        if (PyString_Check(value))
+            getSheetPtr()->setAlias(address, PyString_AsString(value));
+        else if (value == Py_None)
+            getSheetPtr()->setAlias(address, "");
+        else
+            throw Base::TypeError("String or None expected");
+
         Py_Return;
     }
     catch (const Base::Exception & e) {