[Mono-bugs] [Bug 650410] New: Deleting a row in the RowDeleting event causes Detach() exception while cascade delete is on

[bugzilla_noreply at novell.com]

https://bugzilla.novell.com/show_bug.cgi?id=650410

https://bugzilla.novell.com/show_bug.cgi?id=650410#c0


           Summary: Deleting a row in the RowDeleting event causes
                    Detach() exception while cascade delete is on
    Classification: Mono
           Product: Mono: Class Libraries
           Version: 2.6.x
          Platform: x86
        OS/Version: Windows 7
            Status: NEW
          Severity: Normal
          Priority: P5 - None
         Component: Sys.Data
        AssignedTo: mono-bugs at lists.ximian.com
        ReportedBy: cvolzke at live.com.au
         QAContact: mono-bugs at lists.ximian.com
          Found By: ---
           Blocker: ---


User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US)
AppleWebKit/532.5 (KHTML, like Gecko) Chrome/4.1.249.1036 Safari/532.5

In a particular sequence of events:
a) cascade deleting a row in another table while in RowDeleting event
b) having cascade delete on for another relationship
DataRow.Detach() is called twice for the same row.
The test case below works fine on ms.net.


Reproducible: Always

Steps to Reproduce:
Below is the test case:

            DataSet data = new DataSet();
            var t1 = data.Tables.Add("t1");
            var t2 = data.Tables.Add("t2");
            var t3 = data.Tables.Add("t3");

            data.Tables.Remove(t1);
            data.Tables.Remove(t3);
            data.Tables.Add(t1);
            data.Tables.Add(t3);

            t1.Columns.Add("pk");
            t1.Columns.Add("fk");
            t2.Columns.Add("pk");
            t2.Columns.Add("fk");
            t3.Columns.Add("pk");
            t3.Columns.Add("fk");

            t1.Rows.Add(new object[] { "x", "x" });
            t2.Rows.Add(new object[] { "x", "x" });
            t3.Rows.Add(new object[] { "x", "x" });

            var r12 = data.Relations.Add("r12", t1.Columns[0], t2.Columns[1]);
            var r23 = data.Relations.Add("r23", t2.Columns[0], t3.Columns[1]);
            var r31 = data.Relations.Add("r31", t3.Columns[0], t1.Columns[1]);

            r12.ChildKeyConstraint.DeleteRule = Rule.None;
            r23.ChildKeyConstraint.DeleteRule = Rule.Cascade;
            r31.ChildKeyConstraint.DeleteRule = Rule.Cascade;



           
r12.ChildKeyConstraint.Table.Constraints.Remove(r12.ChildKeyConstraint);
            List<DataRow> RowsInCascadeDelete = new List<DataRow>();
            r12.ParentTable.RowDeleting += (sender, e) =>
            {
                if (!RowsInCascadeDelete.Contains(e.Row))
                {
                    RowsInCascadeDelete.Add(e.Row);
                    try
                    {
                        DataRow[] childRows = e.Row.GetChildRows(r12);
                        foreach (DataRow childRow in childRows)
                        {
                            childRow.Delete();
                        }
                    }
                    finally
                    {
                        RowsInCascadeDelete.Remove(e.Row);
                    }
                }
            };

            t2.Rows[0].Delete();

Actual Results:  
An exception is thrown

Expected Results:  
An exception should not be thrown

Tbe fix is straightfoward, if Detach() is called on a DataRow that is already
detached, do nothing:

void Detach ()
{
    --- LINES ADDED ---
    if (RowState == DataRowState.Detached)
        return;
    --- LINES ADDED ---

    Table.DeleteRowFromIndexes (this);
    _table.Rows.RemoveInternal (this);

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