VerifyProperties fails to detect getPagesLibraryExpression as dirty, leading to potential errors further down the road

[heinrich-ulbricht]

Category

• Bug

Describe the bug

I described the bug over here because I initially thought this is an error in the provisioning engine -> pnp/pnpframework#716

Steps to reproduce

Not sure ^^. But see pnp/pnpframework#716 for more text.

Expected behavior

I expect VerifyProperties to detect when RootFolder.ServerRelativeUrl is not loaded yet.

Environment details (development & target environment)

See pnp/pnpframework#716

Additional context

I put lots of Console.WriteLines in the code and this is what I found:

This method:

pnpcore/src/sdk/PnP.Core/Model/Base/BaseDataModel.cs

Line 1275 in cc8858f

private static List<Expression<Func<TModel, object>>> VerifyProperties(IDataModel<TModel> model, Expression<Func<TModel, object>>[] expressions, ref bool dirty)

...fails to handle this expression properly:

pnpcore/src/sdk/PnP.Core/Model/SharePoint/Pages/Internal/Page.cs

Lines 27 to 28 in cc8858f

	private static readonly Expression<Func<IList, object>>[] getPagesLibraryExpression = new Expression<Func<IList, object>>[] {p => p.Title, p => p.TemplateType, p => p.EnableFolderCreation,
	p => p.EnableMinorVersions, p => p.EnableModeration, p => p.EnableVersioning, p => p.ForceCheckout, p => p.RootFolder.QueryProperties(p => p.Properties, p => p.ServerRelativeUrl), p => p.ListItemEntityTypeFullName, p => p.Fields };

Specifically it fails to dive into the properties defined in p.RootFolder.QueryProperties here:

pnpcore/src/sdk/PnP.Core/Model/Base/BaseDataModel.cs

Lines 1299 to 1300 in 119c3ee

	var collection = model.GetPublicInstancePropertyValue(fieldToLoad);
	if (collection is IRequestableCollection)

collection here is of type PnP.Core.Model.SharePoint.Folder (fieldToLoad == "RootFolder"), not IRequestableCollection. This immediately leaves the function leaving the dirty flag unchecked. This leads to errors in other code that now assumes that e.g. the RootFolder.ServerRelativeUrl property is loaded. Because it might not be. And in my case sometimes wasn't.

I have no clue how to fix this ^^

[jansenbe]

@heinrich-ulbricht : this indeed is a bug. When QueryProperties is used to load other collections things work fine, but when another model (e.g. IFolder) is loaded this didn't work. Fix is coming soon.

[jansenbe]

@heinrich-ulbricht : fix has been pushed and will appear in the next nightly release. Closing this issue now, thanks for using PnP Core SDK and reporting the issue.