Use case for AllowExplicitVersion

[jzabroski]

Partial Fixes for dotnet/sdk#2879

[jzabroski]

I'm trying to rework this pull request based on @dsplaisted feedback, but am struggling with how to concisely phrase a recommendation. Suffice to say, I agree with @dsplaisted : AllowExplicitVersion should never be encouraged in the documentation on implicit references, even as a workaround.

[Thraka]

If it shouldn't be encouraged, why would we document it? If we're going to document it, then we should point out why it's discouraged.

[jzabroski]

@Thraka I think AllowExplicitVersion is basically a "measure of last resort". There's a separate discussion between @dsplaisted and I in dotnet/sdk#3046 (comment) - he is still trying to understand my issue, so I think this PR is in a holding pattern until we can come up with a permanent solution.

So, while I agree with you documentation is the end goal, I'd rather get it right once than rush something out the door.

[Thraka]

OK I've labeled this issue. :) Just follow up when you have the right wording.

[jzabroski]

@Thraka I have sent @dsplaisted a full repro sln that I've uploaded to my GitHub, as part of dotnet/sdk#3046 (comment) - this repro puts an interesting twist as it seems to indicate in some cases AllowExplicitVersion is absolutely required. What I don't understand is why, and I am hoping Daniel can shed light on it, as in a more complicated solution, his advice to include the metapackage on Tests project works. In my simpler repro, his advice does not work, which indicates my PR may be valid after all.

[Thraka]

@jzabroski any update?

[jzabroski]

@dsplaisted and I closed the related issue - I think that we don't have a good use case for AllowExplicitVersion, other than perhaps the same scenarios solved by TargetFrameworkVersion here: https://docs.microsoft.com/en-us/dotnet/core/versions/selection#self-contained-deployments-include-the-selected-runtime - except, instead of framework version, there might be a case where you need to load a specific version of a third-party library. Either because a bugfix breaks your program (e.g., surfaces a race condition), or because you're trying to reduce the scope of regression testing (human resource constraints) in a mechanical way.

[Thraka]

@jzabroski I closed this, you could rollback your delete and keep the content, but as it stands right now, the PR doesn't contain any changes.

[jzabroski]

@Thraka Sorry Andy, I was trying to think of where AllowExplicitVersion should go. I think csproj.md is the right place, but was fumbling with where to put it.

[Thraka]

I think it's a good place for it right now. We're going to rework this article eventually. I think that after this section would be good: https://docs.microsoft.com/en-us/dotnet/core/tools/csproj#implicit-version-for-some-package-references