Fixes NullReferenceException with recursive GetVortoValue

[drangus]

Fix for NullReferenceException when calling GetVortoValue : allow return of defaultValue or if the recursive parameter set true traversal up the tree.

[leekelleher]

Thanks @drangus! 🎉 I've updated the PR with whitespace formatting - to match the current code style.

Once @mattbrailsford is happy, we can merge it in 👍

[sniffdk]

Was just about to submit a PR for this as well. This change should also be added to DoInnerHasVortoValue.

[sniffdk]

Imho the unnecessary nesting should be replaced with something like
if (prop == null)
{
return defaultValue;
}

[tristanjthompson]

Was just going to raise an issue/PR for this! Might it be approved/merged/released soon? Anything I can do to help?

[mattbrailsford]

This has now been merged in (and tweaked as per @sniffdk's suggestions) and is available via the build server https://ci.appveyor.com/project/UMCO/umbraco-vorto/build/1.6.1.114/artifacts or via MyGet https://www.myget.org/gallery/umbraco-packages.

I'll have a chat with @leekelleher to see if we push a release out now, or try and address any of the open issues first.

[drangus]

The applied patch doesn't allow recursion!

Change to:

if (prop == null)
{
    // PR #100 - Prevent generation of NullReferenceException: allow return of defaultValue or traversal up the tree if prop is null
    //return defaultValue;
    return recursive && content.Parent != null? content.Parent.DoGetVortoValue<T>(propertyAlias, cultureName, recursive, defaultValue) : defaultValue;
}