Regression? Plugin Parameter Injection

[Chris Graham]

Hey All.

I'm not sure if I've found a regression issue with Maven 3.0.x (tried with
all versions beta-1 onwards to 3.0.5) or not. V3.x behaves differently to
2.09, 2.0.11 and 2.2.1.

I've written a plugin for WebSphere Message Broker; basically it's a
wrapper for the underlying mqsicreatebar tool.

Amongst other things, it takes zero or more message sets and message flows.
To handle this, I defined the parameters as an array.

Here is the snippet from the plugin's source:
    /**
     * The message flows to be added to the bar file.
     * @parameter expression="${msgFlows}"
     * @required
     */
    private String[] msgFlows;

    /**
     * The message sets to be added to the bar file.
     * @parameter expression="${msgSets}"
     * @required
     */
    private String[] msgSets;

and here is an example configuration section from a pom that uses the
plugin:

                <configuration>
                    <skipApplyOverrides>false</skipApplyOverrides>
                    <isV60>true</isV60>
                    <workspace>${wmbtk.workspace.root}/24a</workspace>
                    <msgFlows>

<msgFlow>MFP_Project/com/blah/MFL_DiagFlow.msgflow</msgFlow>
                    </msgFlows>
                    <msgSets>
                        <msgSet />
                    </msgSets>
                </configuration>

So we have one message flow, but no message sets.

Here is where the differences are seen.

Maven 2.0.9, 2.0.11 and 2.2.1 will initialise the msgSets as null.

Maven 3.0 (beta-1 to 3.0.5) will initialise msgSets as a single element of
null.

My question boils down to: is this the desired behaviour?

I've had to adjust my code to work under Maven 3.x (which I didn't think
that I had too).

>From memory, I can not supply an empty <msgSets/> element (but I need to
check that).

-Chris