AppSourceCop Error AS0022

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An external scope cannot be removed

Description

An external scope cannot be removed.

Remarks

This rule verifies that procedures which were exposed to dependent extensions in the previous version of the extension, remain exposed to other extensions.

The availability of a procedure is defined by:

  • the access modifier set on the object declaring the procedure
  • the access modifier set on the procedure
  • the Scope attribute that is added on the procedure

Code examples triggering the rule

In the following examples, version 1.0 of the extension defines a procedure which is public and available for Cloud development.

Version 1.0 of the extension:

codeunit 50100 MyCodeunit
{
    [Scope('Cloud')]
    procedure MyProcedure()
    begin
    end;
}

Example 1 - Adding a local access modifier

Version 2.0 of the extension:

codeunit 50100 MyCodeunit
{
    [Scope('Cloud')]
    local procedure MyProcedure()
    begin
    end;
}

In version 2.0, the procedure is only accessible within its declaring codeunit. If a dependent extension called this procedure, this will lead to a compilation error similar to 'MyProcedure()' 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
{
    procedure AnotherMethod()
    var
        c: Codeunit MyCodeunit;
    begin
        c.MyProcedure();
    end;
}

Example 2 - Changing the Scope attribute from 'Cloud' to 'OnPrem'

Version 2.0 of the extension:

codeunit 50100 MyCodeunit
{
    [Scope('OnPrem')]
    procedure MyProcedure()
    begin
    end;
}

In version 2.0, the procedure is only available for OnPrem development. If a dependent extension uses the Cloud compilation target in the app.json and calls this procedure, this will lead to a compilation error similar to The type or method 'MyProcedure' cannot be used for 'Extension' development. (AL0296).

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

codeunit 50120 AnotherCodeunit
{
    procedure AnotherMethod()
    var
        c: Codeunit MyCodeunit;
    begin
        c.MyProcedure();
    end;
}

Code examples not triggering the rule

In the following examples, version 1.0 of the extension defines a procedure which does not have a return type.

Version 1.0 of the extension:

codeunit 50100 MyCodeunit
{
    [Scope('OnPrem')]
    procedure MyOnPremProcedure()
    begin
    end;

    local procedure MyLocalProcedure()
    begin
    end;
}

Example 1 - Removing a local access modifier

Version 2.0 of the extension:

codeunit 50100 MyCodeunit
{
    [Scope('OnPrem')]
    procedure MyOnPremProcedure()
    begin
    end;

    procedure MyLocalProcedure()
    begin
    end;
}

In version 2.0, the procedure MyLocalProcedure is now public and becomes available to dependent extensions.

Example 2 - Changing the Scope attribute from 'OnPrem' to 'Cloud'

Version 2.0 of the extension:

codeunit 50100 MyCodeunit
{
    [Scope('Cloud')]
    procedure MyOnPremProcedure()
    begin
    end;

    local procedure MyLocalProcedure()
    begin
    end;
}

In version 2.0, the procedure MyOnPremProcedure becomes available for both OnPrem and Cloud development. Any dependent extension can now call this procedure, regardless of the compilation target specified in their app.json. The default Scope of a procedure is Cloud. Removing the attribute is then also allowed.

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