tdf#85371 - grant write access to the method used as a variable

During the creation of the parameter list of a method, explicitly grant
write access to the method which will used as a variable. Otherwise, the
name of the method can't be used in certain statements, i.e., index in a
for loop or as a dimension in ReDim.

Change-Id: I3e4c49c21fd3345d5ddd69bc31a5823b5de5b8e7
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/104696
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>

2 files changed, 75 insertions, 0 deletions

diff --git a/basic/qa/basic_coverage/test_method_name_variable.vb b/basic/qa/basic_coverage/test_method_name_variable.vb
new file mode 100644
index 000000000000..ea45366c0f7d
--- /dev/null
+++ b/basic/qa/basic_coverage/test_method_name_variable.vb
@@ -0,0 +1,35 @@
+' This file is part of the LibreOffice project.
+'
+' This Source Code Form is subject to the terms of the Mozilla Public
+' License, v. 2.0. If a copy of the MPL was not distributed with this
+' file, You can obtain one at http://mozilla.org/MPL/2.0/.
+'
+
+Function assignVarToMethod() As Integer
+
+    ' method name used as dimension specifier
+    Dim fieldOfLongs() As Long
+    ReDim fieldOfLongs(assignVarToMethod) As Long
+
+    ' method name used as loop index
+    Dim sum As Integer
+    For assignVarToMethod = 1 To 3
+        sum = sum + assignVarToMethod
+    Next assignVarToMethod
+    assignVarToMethod = sum
+
+End Function
+
+Function doUnitTest() As Integer
+
+    doUnitTest = 0
+
+    ' tdf#85371 - check if the name of the method can be used as a variable in certain statements
+    If (assignVarToMethod() <> 6) Then Exit Function
+    ' tdf#85371 - check if an assignment to the function fails outside of the function itself
+    assignVarToMethod = 0
+    If (assignVarToMethod() <> 6) Then Exit Function
+
+    doUnitTest = 1
+
+End Function
diff --git a/basic/source/runtime/runtime.cxx b/basic/source/runtime/runtime.cxx
index 498c71628dba..0606b78ca420 100644
--- a/basic/source/runtime/runtime.cxx
+++ b/basic/source/runtime/runtime.cxx
@@ -83,6 +83,34 @@ using namespace ::com::sun::star;
 static void lcl_clearImpl( SbxVariableRef const & refVar, SbxDataType const & eType );
 static void lcl_eraseImpl( SbxVariableRef const & refVar, bool bVBAEnabled );
 
+namespace
+{
+class ScopedWritableGuard
+{
+public:
+    ScopedWritableGuard(const SbxVariableRef& rVar, bool bMakeWritable)
+        : m_rVar(rVar)
+        , m_bReset(bMakeWritable && !rVar->CanWrite())
+    {
+        if (m_bReset)
+        {
+            m_rVar->SetFlag(SbxFlagBits::Write);
+        }
+    }
+    ~ScopedWritableGuard()
+    {
+        if (m_bReset)
+        {
+            m_rVar->ResetFlag(SbxFlagBits::Write);
+        }
+    }
+
+private:
+    SbxVariableRef m_rVar;
+    bool m_bReset;
+};
+}
+
 bool SbiRuntime::isVBAEnabled()
 {
     bool bResult = false;
@@ -1131,6 +1159,9 @@ void SbiRuntime::PushFor()
     p->refEnd = PopVar();
     SbxVariableRef xBgn = PopVar();
     p->refVar = PopVar();
+    // tdf#85371 - grant explicitly write access to the index variable
+    // since it could be the name of a method itself used in the next statement.
+    ScopedWritableGuard aGuard(p->refVar, p->refVar.get() == pMeth);
     *(p->refVar) = *xBgn;
     nForLvl++;
 }
@@ -2583,6 +2614,9 @@ void SbiRuntime::StepNEXT()
         StarBASIC::FatalError( ERRCODE_BASIC_INTERNAL_ERROR );
         return;
     }
+    // tdf#85371 - grant explicitly write access to the index variable
+    // since it could be the name of a method itself used in the next statement.
+    ScopedWritableGuard aGuard(pForStk->refVar, pForStk->refVar.get() == pMeth);
     pForStk->refVar->Compute( SbxPLUS, *pForStk->refInc );
 }
 
@@ -3360,7 +3394,13 @@ void SbiRuntime::StepBASED( sal_uInt32 nOp1 )
     sal_uInt16 uBase = static_cast<sal_uInt16>(nOp1 & 1);       // Can only be 0 or 1
     p1->PutInteger( uBase );
     if( !bCompatible )
+    {
+        // tdf#85371 - grant explicitly write access to the dimension variable
+        // since in Star/OpenOffice Basic the upper index border is affected,
+        // and the dimension variable could be the name of the method itself.
+        ScopedWritableGuard aGuard(x2, x2.get() == pMeth);
         x2->Compute( SbxPLUS, *p1 );
+    }
     PushVar( x2.get() );  // first the Expr
     PushVar( p1 );  // then the Base
 }