Clear grid attribute cache when loading new table

Clear the cached attributes when replacing the table they were used
with.

Add unit test checking that the attributes are not used any longer.

Closes #23607.

src/generic/grid.cpp

@@ -2866,6 +2866,9 @@ wxGrid::SetTable(wxGridTableBase *table,
             HideCellEditControl();
             m_cellEditCtrlEnabled = false;
 
+            // Don't hold on to attributes cached from the old table
+            ClearAttrCache();
+
             m_table->SetView(nullptr);
             if( m_ownTable )
                 delete m_table;

tests/controls/gridtest.cpp

@@ -1793,6 +1793,165 @@ TEST_CASE_METHOD(GridTestCase, "Grid::CellAttribute", "[attr][cell][grid]")
     }
 }
 
+namespace SetTable_ClearAttrCache
+{
+
+static unsigned int drawCount1;
+
+class Renderer1 : public wxGridCellRenderer
+{
+public:
+    virtual void Draw(wxGrid& grid,
+                      wxGridCellAttr& attr,
+                      wxDC& dc,
+                      const wxRect& rect,
+                      int row, int col,
+                      bool isSelected) override
+    {
+        ++drawCount1;
+        wxGridCellRenderer::Draw(grid, attr, dc, rect, row, col, isSelected);
+    }
+
+    virtual wxSize GetBestSize(wxGrid& /*grid*/,
+                               wxGridCellAttr& /*attr*/,
+                               wxDC& /*dc*/,
+                               int /*row*/, int /*col*/) override
+        { return wxSize(111, 111); }
+
+    virtual wxGridCellRenderer *Clone() const override
+        { return new Renderer1(*this); }
+};
+
+class Attr1 : public wxGridCellAttr
+{
+public:
+    Attr1()
+    {
+        SetRenderer(new Renderer1);
+    }
+};
+
+static unsigned int drawCount2;
+
+class Renderer2 : public wxGridCellRenderer
+{
+public:
+    virtual void Draw(wxGrid& grid,
+                      wxGridCellAttr& attr,
+                      wxDC& dc,
+                      const wxRect& rect,
+                      int row, int col,
+                      bool isSelected) override
+    {
+        ++drawCount2;
+        wxGridCellRenderer::Draw(grid, attr, dc, rect, row, col, isSelected);
+    }
+
+    virtual wxSize GetBestSize(wxGrid& /*grid*/,
+                               wxGridCellAttr& /*attr*/,
+                               wxDC& /*dc*/,
+                               int /*row*/, int /*col*/) override
+        { return wxSize(222, 222); }
+
+    virtual wxGridCellRenderer *Clone() const override
+        { return new Renderer2(*this); }
+};
+
+class Attr2 : public wxGridCellAttr
+{
+public:
+    Attr2()
+    {
+        SetRenderer(new Renderer2);
+    }
+};
+
+class AttrProvider : public wxGridCellAttrProvider
+{
+public:
+    AttrProvider(wxGridCellAttr* attr_)
+        : attr(attr_)
+    {
+    }
+
+    ~AttrProvider()
+    {
+        attr->DecRef();
+    }
+
+    virtual wxGridCellAttr *GetAttr(int /*row*/, int /*col*/,
+                                    wxGridCellAttr::wxAttrKind  /*kind*/ ) const override
+    {
+        attr->IncRef();
+        return attr;
+    }
+protected:
+    wxGridCellAttr* attr;
+};
+
+class GridTable1 : public wxGridTableBase
+{
+public:
+    GridTable1()
+    {
+        SetAttrProvider(new AttrProvider(new Attr1));
+    }
+
+    virtual int GetNumberRows() override { return 1; }
+    virtual int GetNumberCols() override { return 1; }
+    virtual wxString GetValue( int /*row*/, int /*col*/ ) override { return wxS("1"); }
+    virtual void SetValue( int /*row*/, int /*col*/, const wxString& /*value*/ ) override { }
+};
+
+class GridTable2 : public wxGridTableBase
+{
+public:
+    GridTable2()
+    {
+        SetAttrProvider(new AttrProvider(new Attr2));
+    }
+
+    virtual int GetNumberRows() override { return 2; }
+    virtual int GetNumberCols() override { return 2; }
+    virtual wxString GetValue( int /*row*/, int /*col*/ ) override { return wxS("2"); }
+    virtual void SetValue( int /*row*/, int /*col*/, const wxString& /*value*/ ) override { }
+};
+
+} // namespace SetTable_ClearAttrCache
+
+TEST_CASE_METHOD(GridTestCase, "Grid::SetTable_ClearAttrCache", "[grid]")
+{
+    // Set up tables of different custom types, each with its
+    // own custom renderer. Switch the grid between them and
+    // check that the correct renderer is called each time
+    // (testing that the grid's attrCache isn't reusing stale values)
+
+    // Fails on OSX (renderer hasn't been called by the time the checks are done?)
+#if !defined(__WXOSX__)
+    using namespace SetTable_ClearAttrCache;
+
+    GridTable1 table1;
+    GridTable2 table2;
+
+    drawCount1 = drawCount2 = 0;
+    m_grid->SetTable(&table2);
+    m_grid->Refresh();
+    m_grid->Update();
+    CHECK(drawCount1 == 0);
+    CHECK(drawCount2 == 2*2);
+
+    drawCount1 = drawCount2 = 0;
+    m_grid->SetTable(&table1);
+    m_grid->Refresh();
+    m_grid->Update();
+    CHECK(drawCount1 == 1*1);
+    CHECK(drawCount2 == 0);
+
+    // Remove the grid table before our local objects go out of scope
+    m_grid->SetTable(nullptr);
+#endif // !__WXOSX__
+}
+
 #define CHECK_MULTICELL() CHECK_THAT( *m_grid, HasMulticellOnly(multi) )
 
 #define CHECK_NO_MULTICELL() CHECK_THAT( *m_grid, HasEmptyGrid() )