Rule M2.4 exception : this error should NEVER happen! If you can provide the triggering file, then please raise a bug at https://bz.apache.org/bugzilla/enter_bug.cgi?product=POI and attach a file that triggers it, thanks!

[Maz4Life]

I create a class that inherit from XSSFWorkbook:

public class ExtensionsXSSFWorkbook : NPOI.XSSF.UserModel.XSSFWorkbook
    {
        public ExtensionsXSSFWorkbook() : base() { }
        public ExtensionsXSSFWorkbook ShallowCopy()
        {
            Clear();
            GetCTWorkbook().sheets.sheet.Clear();
            var rel = GetRelations();   
            for(int i = 2; i < rel.Count; i++)
            {
                RemoveRelation(rel[i]);
            }
            ExtensionsXSSFWorkbook currentworkbook = (ExtensionsXSSFWorkbook)this.MemberwiseClone();
            return currentworkbook; 
        }
    }

I have under class that create instance of this class like this:

            workbooktemplate = new ExtensionsXSSFWorkbook();
            //**************define green style for a cell********************
            green = workbooktemplate.CreateCellStyle();
            green.FillForegroundColor = IndexedColors.Green.Index;
            green.FillPattern = FillPattern.SolidForeground;
            green.Alignment = HorizontalAlignment.Center;
            //**************end of definition********************

            //**************define red style for a cell********************
            red = workbooktemplate.CreateCellStyle();
            red.FillForegroundColor = IndexedColors.Red.Index;
            red.FillPattern = FillPattern.SolidForeground;
            red.Alignment = HorizontalAlignment.Center;
            //**************end of definition********************

            //**************define grey style for a cell********************
            grey = workbooktemplate.CreateCellStyle();
            grey.FillForegroundColor = IndexedColors.Grey25Percent.Index;
            grey.FillPattern = FillPattern.SolidForeground;
            grey.Alignment = HorizontalAlignment.Center;
            //**************end of definition********************

After it create excel document and use the "ShallowCopy" method.
like this:
XSSFWorkbook workbook = workbooktemplate.ShallowCopy();

the error happened only the second time of the use "ShallowCopy" method.
it fail on the RemoveRelation(rel[i]) line.

the fail only happened in the second time because just the I try to delete the old sheets from the first round.

I sorry that I can't give you the full code but it use inside TPI of my company

I hoped that I gave you enough information to discover the bug.

[tonyqus]

I don't think this is a bug. The extension method ShallowCopy you created caused this issue. What are you going to do by this method? Clone workbook?

[Maz4Life]

Of course, it is a bug. Your class doesn’t support Shallow Copy. If the shallow copy is enabled, I can use the same base workbook, which will be faster than repeatedly defining the colors used for the cell. The colors will be defined only once in the constructor. The problem that I need to do is “workbook.Close();” that deleting or disabling something in the “Relation” list. If I will not do “workbook.Close();” it will not load the new excel. Guy From: Tony Qu ***@***.***> Sent: יום ב 21 נובמבר 2022 00:35 To: nissl-lab/npoi ***@***.***> Cc: Katz, Guy ***@***.***>; Author ***@***.***> Subject: Re: [nissl-lab/npoi] Rule M2.4 exception : this error should NEVER happen! If you can provide the triggering file, then please raise a bug at https://bz.apache.org/bugzilla/enter_bug.cgi?product=POI and attach a file that triggers it, thanks! (Discussi... I don't think this is a bug. The extension method ShallowCopy you created cause his issue. What are you going to do by this method? Clone workbook? — Reply to this email directly, view it on GitHub<#919 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/AZQUJNJHN5IIDCZ2JVI2XILWJKRSZANCNFSM6AAAAAAQGZRQ7M>. You are receiving this because you authored the thread.Message ID: ***@***.***> --------------------------------------------------------------------- Intel Israel (74) Limited This e-mail and any attachments may contain confidential material for the sole use of the intended recipient(s). Any review or distribution by others is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies.

[tonyqus]

You are the first user to clone workbook by shadowcopy. If you wanna reuse workbook template, I suggest you create a template xlsx and save it as a file. Reopen it with NPOI and continue what you wanna do. This is the right way.