Support net8.0 - Avoid evaluating Current on an empty enumerator

[lewing]

Issues

This pull request fixes #2796

Description

Avoid calling .Current on an empty enumerator. Calling Current is not valid unless MoveNext() has returned true and in net8.0 this was enforced.

Checklist (Uncheck if it is not completed)

• [ ] Test cases added
• [ ] Build and test with one-click build and test script passed

Additional work necessary

If documentation update is needed, please add "Docs Needed" label to the issue and provide details about the required document change in the issue.

[lewing]

I went with the simplest possible fix here at first but decided to make it more performant and readable (to me at least) by avoiding iterating at all.

        public ODataPathInfo(ODataPath odataPath)
        {
            ODataPathSegment targetSegment = odataPath.LastSegment;

            if (targetSegment != null)
            {
                // use next to last segment if the last one is Key or Count Segment
                if ((targetSegment is KeySegment || targetSegment is CountSegment) && odataPath.Count > 1)
                {
                    targetSegment = odataPath[odataPath.Count - 2];
                }

                this.targetNavigationSource = targetSegment.TargetEdmNavigationSource;
                this.targetEdmType = targetSegment.EdmType;
                if (this.targetEdmType != null)
                {
                    IEdmCollectionType collectionType = this.targetEdmType as IEdmCollectionType;
                    if (collectionType != null)
                    {
                        this.targetEdmType = collectionType.ElementType.Definition;
                    }
                }
            }

            this.segments = odataPath;
        }

[richlander]

FYI: I was at the .NET Booth at Build today. A customer told me that the associated bug is their primary/only blocker from moving to .NET 8. It would be great to see this fix merged.

Thanks in advance.

[Stephanvs]

FYI: I was at the .NET Booth at Build today. A customer told me that the associated bug is their primary/only blocker from moving to .NET 8. It would be great to see this fix merged.

Thanks in advance.

Same thing is true in my case as well. Hope to see this fixed soon! 👍

[lewing]

cc @ElizabethOkerio (I can't request reviewers)

[habbes]

@lewing good call to avoid enumeration. That code must have been written before we added an indexer to ODataPath.

[habbes]

FYI: I was at the .NET Booth at Build today. A customer told me that the associated bug is their primary/only blocker from moving to .NET 8. It would be great to see this fix merged.

Thanks in advance.

@richlander is that customer an OData user?

[richlander]

@habbes -- yes. They told me use the odata package on nuget.org. I have not seen them again at the booth.

[richlander]

Looks like the commit got reverted @mikepizzo? Were there test failues?

[mikepizzo]

@gathogojr wanted to add some specific tests for the (previously) failing case. He will add the tests and do a build tonight.

[mikepizzo]

I restored the previous commit as John has added his tests to a separate PR.