Code and tests for issue #2567

[supergibbs]

URLs like https://www.nuget.org/packages/PACKAGE/absoluteLatest will display the latest version.

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[supergibbs]

Any update on this PR? @ryuyu @skofman1

[skofman1]

Hi @supergibbs, thanks for the PR!

Can you please explain what is the feature you are implementing and why this feature is important, and in what scenarios?

Thanks!

[supergibbs]

Sure, please see my #2567 (comment)

[skofman1]

Thanks @supergibbs . @ryuyu will review the PR and merge it.

[ryuyu]

@supergibbs A few issues here.

1. The VersionRouteConstraint needs to be updated to allow the "prerelease" string as a valid version (https://github.com/NuGet/NuGetGallery/blob/master/src/NuGetGallery/App_Start/VersionRouteConstraint.cs)
2. FindPackageByIdAndVersion should not accept "prerelease" as a valid version string. We should instead add a new method that gets called by the view specially when we pass "prerelease".
3. Recognition of the "prerelease" url should be at the view level, in DisplayPackage (https://github.com/NuGet/NuGetGallery/blob/master/src/NuGetGallery/Controllers/PackagesController.cs#L301). This method should be updated to call the new helper we add above.

This is so that we add this explicitly on only the display endpoint. The rest of the endpoints should require specifying a version (these are inserted on the page when the page is created).

Thanks!

[supergibbs]

Thanks for the notes @ryuyu. I started over off the latest dev branch and re-implemented accordingly. Let me know if there is anything else!

[ryuyu]

Add a null check (version != null) here before we do the equals check.
Currently, it will throw if you try to go to an empty version url (Ie nuget.org/packages/{id}/)

[supergibbs]

Good catch, I added a test for that too.

[ryuyu]

Let's drop this condition and change the name of this method to FindAbsoluteLatestPackageById.
This way, if a package has no prerelease versions, the call to this will return whatever is the most recent.

[supergibbs]

Sounds good, how do you feel about filtering out unlisted packages? I feel like that is what most owners would want. Possibly in FindPackageByIdAndVersion() too when version is null.

[ryuyu]

Let's change this string from "prerelease" to "absoluteLatest" or something of that nature.
With the other changes suggested, this will make it behave as expected if the most recent version is a prerelease, and it is still descriptive of the case where there are no prerelease versions.

[supergibbs]

Will do. Should I add this "magic string" to the Constants.cs/somewhere else or are you okay with it as is?

Used in two places and two tests

[ryuyu]

Hmmm. Yea that seems like a good idea. Let's call it AbsoluteLatestUrlString or something of that nature.

[ryuyu]

👍
A few suggestions here, but it's looking good.
I think we should change the url from "prerelease" to something like "absoluteLatest" so that it is descriptive of the case where the most recent version is not a prerelease version, or in the case where a package has no prerelease versions.

-Thanks!