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AppSourceCop Error AS0036

  • Article

Unsupported table field property change

Description

Modifying table field properties can lead to destructive changes that will break the upgrade of existing installations and dependent extensions.

It's not allowed to change property values in a way that would prevent the schema synchronization of the extension on existing installations, or that would break dependent extensions.

Code examples triggering the rule

Example 1 - Changing Enabled from true to false

Version 1.0 of the extension:

table 50100 MyTable
{
    fields
    {
        field(1; MyField; Integer)
        {
            Enabled = true; // This is also the default value.
        }
    }
}

Version 2.0 of the extension:

table 50100 MyTable
{
    fields
    {
        field(1; MyField; Integer)
        {
            Enabled = false;
        }
    }
}

In version 2.0, the field is not enabled anymore. Disabled fields are not created in the database during schema synchronization. Disabling a field is then similar to removing the field and is then a destructive change.

Example 2 - Changing FieldClass from Normal to FlowField

Version 1.0 of the extension:

table 50100 MyTable
{
    fields
    {
        field(1; MyField; Integer)
        {
            FieldClass = Normal; // This is also the default value.
        }
    }
}

Version 2.0 of the extension:

table 50100 MyTable
{
    fields
    {
        field(1; MyField; Integer)
        {
            FieldClass = FlowField; 
        }
    }
}

In version 2.0, the field became a FlowField. As FlowFields are not physical fields that are stored in the database, they are not created during schema synchronization. Changing a Normal field to FlowField is a then destructive change.

Example 3 - Changing the Access property to make a field less accessible

Version 1.0 of the extension:

table 50100 MyTable
{
    fields
    {
        field(1; MyField; Integer)
        {
            Access = Public; // This is also the default value.
        }
    }
}

Version 2.0 of the extension:

table 50100 MyTable
{
    fields
    {
        field(1; MyField; Integer)
        {
            Access = Local; 
        }
    }
}

In version 2.0, the field MyField is now only accessible within MyTable and cannot be used from other extension. If a dependent extension references this field, this will lead to a compilation error similar to 'MyField' is inaccessible due to its protection level (AL0161).

For example, the following extension compiles when depending on version 1.0, but fails to compile with version 2.0:

codeunit 50120 AnotherCodeunit
{
    trigger OnRun()
    var
        r: Record MyTable;
    begin
        r.MyField := 1;
    end;
}

Code examples not triggering the rule

Example 1 - Setting Enabled from false to true

Version 1.0 of the extension:

table 50100 MyTable
{
    fields
    {
        field(1; MyField; Integer)
        {
            Enabled = false;
        }
    }
}

Version 2.0 of the extension:

table 50100 MyTable
{
    fields
    {
        field(1; MyField; Integer)
        {
            Enabled = true; // This is also the default value.
        }
    }
}

In version 2.0, the field is now enabled. Disabled fields are not created in the database during schema synchronization. For the schema synchronization, enabling a field is then similar to creating a new field and is then not a destructive change.

Example 2 - Changing FieldClass from FlowField to Normal

Version 1.0 of the extension:

table 50100 MyTable
{
    fields
    {
        field(1; MyField; Integer)
        {
            FieldClass = FlowField;
        }
    }
}

Version 2.0 of the extension:

table 50100 MyTable
{
    fields
    {
        field(1; MyField; Integer)
        {
            FieldClass = Normal; // This is also the default value.
        }
    }
}

In version 2.0, the FlowField became a Normal field. As FlowFields are not physical fields that are stored in the database, they are not created during schema synchronization. For the schema synchronization, changing a flow field to a normal field is similar to creating a new field and is then not a destructive change.

Example 3 - Changing the Access property to make a field more accessible

Version 1.0 of the extension:

table 50100 MyTable
{
    fields
    {
        field(1; MyField; Integer)
        {
            Access = Protected;
        }
    }
}

Version 2.0 of the extension:

table 50100 MyTable
{
    fields
    {
        field(1; MyField; Integer)
        {
            Access = Public; 
        }
    }
}

In version 1.0, MyField was accessible to table extensions extending MyTable. In version 2.0, it is now accessible to other extensions both in and outside of table extensions extending MyTable. This is not a breaking change.

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