Why this.proforma() Is Not Reliable in Batch and Why prepareProforma() Exists in D365 Finance and Operations

A proforma posting intentionally rolls back all database changes after the document is generated. Microsoft has confirmed that proforma runs are effectively “print‑only” operations that leave no persistent system trace unless custom logic explicitly runs outside the posting transaction.
This rollback behavior already makes proforma detection fragile if your logic depends on state after posting.

Batch execution changes the call stack and lifecycle

• SalesFormLetter_* instances may be reused
• afterOperationBody() may execute outside the scope where the proforma flag is meaningful
• The boolean behind this.proforma() can be reset, defaulted, or evaluated too late

Microsoft explicitly introduced prepareProforma() for batch correctness

• It is invoked only for proforma runs
• It executes per journal being processed
• It runs at the correct time in the batch lifecycle, before posting/rollback occurs
• It is safe for multi‑threaded execution

[ExtensionOf(classStr(SalesFormLetter_Confirm))]
final class SalesFormLetter_Confirm_StoneridgeSoftware_Extension
{
    protected void afterOperationBody()
    {
        // This is a manual/UI run.
        // For batched/multithreaded SO Confirm, see FormletterService_StoneridgeSoftware_Extension
        next afterOperationBody();
        if (this.proforma() && !this.isInBatch())
        {
            Common sourceTable = this.parmSourceTable();

            if (sourceTable && sourceTable.TableId == tableNum(SalesTable))
            {
                SalesTable salesTable = sourceTable as SalesTable;
                // TODO ACTION
            }

        }
    }
}

[ExtensionOf(classStr(FormletterService))]
final class FormletterService_StoneridgeSoftware_Extension
{
    // prepareProforma is called only during batched run, and it is per journal post being processed
    protected void prepareProforma(FormletterJournalPost _formletterJournalPost)
    {
        // Handle SO Confirmations
        if(this.documentStatus == DocumentStatus::Confirmation && this.formletterType == formletterType::Sales)
        {
            ParmId parmIdLoc = this.parmId;
            SalesTable salesTable;
            SalesParmSubTable salesParmSubTable;
            ttsbegin;
            while select forupdate salesTable
                            join salesParmSubTable
                            where salesParmSubTable.ParmId == parmIdLoc
                            && salesTable.SalesId == salesParmSubTable.OrigSalesId
            {
                // TODO ACTION
            }
            ttscommit;
           
        }
        next prepareProforma(_formletterJournalPost);
}