Add support for autogenerated binding redirects that are not source controlled

[julealgon]

Add support for autogenerated binding redirects that are not source controlled

[CZEMacLeod]

@julealgon This has been tried by various people, but there are a large number of downsides to this that have been encountered.
The main points (from memory)

• The project may not build at all without the redirects file
• Intellisense etc. won't work on the first compile, so a developer would have to build multiple times after checking out the code.
• Similarly, it could require multiple builds before it could run.
• A build server would fail the first build and require special logic.
• configSource is a bit flaky for bindings as the folder path is not always relative to the project root.
• Publishing a project is more difficult as the non-controlled file is difficult to include.
• You don't have an easy way to make the project deterministic for rebuilding older versions.
• The mechanism uses the net sdk built in mechansim for generating redirects which does not support this and thus it would require custom code, and/or a lot of additional messing about to get it to work.
• This is more complicated when you have multiple web.config files, such as when you are using MVC and/or RazorGenerator.

If you can get a reliable system in place for this, I'm open to a PR to add the additional mode, but I feel there would have to be a lot of documentation about the drawbacks and limitations.

If you are working in a multi-developer scenario, I would hope that you are running unit tests before checking in the code/merging changes. You could set up a check to prevent accepting PRs if the build results in a binding issue.
Alternatively (and it is what I do) - if a build on the build server after a check in of say a package update, results in changes to web.config, add that change as a new commit. (This is what I do.)

[NickCraver]

I don't have a great solution to this at the moment either, but the #1 problem here is over redirecting because of the commits, as well as cherry-picking back to release branches. Both of these get pretty painful.

For example if you have a package that depends on X and causes a redirect for X because it ultimately bumped X to say 5.0.0, we get a redirect. That redirect is then committed to source control. Package gets updated, drops the need for X, the redirect to 5.0.0, which isn't the version we're at anymore (say it's back to 2.0.0). If no redirect is needed at all (everything else needed 2.0.0), everything is happy but the redirect is wrong and we get a runtime boom. Compared to any app.config where everything is generated to the output directory, but not checked in...this all just works, with the right redirects.

But I take some the above points, doing this only in publish (basically generate, without erroring in the build) may not be for everyone. Just adding some thoughts in case it adds ideas here, I'd love to make this work as it's one of the main pain points we have left in builds/runtime at all.

[leusbj]

@NickCraver, @julealgon

A stopgap idea might be to create a build target that runs only during a clean and uses a XmlPeek/XmlPoke/TransformXML task to entirely remove the <AssemblyBinding> section of the web.config. You could then ask all members of the team to only "check-in" after having "cleaned" the solution. This would keep your repo clean of redirects and give a stable starting point for each team members.

There might be one other possibility that I haven't seen yet mentioned as a solution to this situation, and that is to "treat" the project root web.config file as an "intermediate" or "generated" file.

The Pro's:

• The web.config file itself can be excluded from source repo (line item in .gitignore; .tfignore)
• All developer chosen items/values are defined in some other baseconfig file which IS included in the source control
• The web.config can be made to be generated "early" in the build process so it is present before GenerateBindingRedirects process
• The web.config can be updated directly by the GenerateBindingRedirects process since the file is entirely generated by the build
• The web.config file in project root will be present by "run/debug" time, because build runs before debug start, so local debugging will work
• The Web.config file in project root will be present by "package" time, because build runs before package step, so MSDeploy and folder packaging will include it.

The Con's:

• Pattern of having web.config be ignored by source control will seem odd/unexpected to many developers
• Pattern of having Developer chosen items/values stored in a differnt place will need to be communicated to all members to the dev team
• No "easy button" (meaning no automated tooling) mechanism to convert projects to this new pattern, so a manual process will need to be used for each project
• Older nuget packages authored expecting Packages.config style references frequently make use of install.ps1, web.config.install.xdt, and hardcoded assumptions about "web.config" being present, so each individual referenced package would need to be evaluated regarding any elements that need to be placed into the baseconfig file

I haven't yet built out this idea robust enough to offer to include it with this project type, so I don't have a ready-made solution for you. But perhaps in your situation you can mitigate the negatives in order to gain the benefits.

Some combination of ideas (t4 generation or TransfromXML build steps) will allow you to generate the web.config dynamically at build time (building it up from other files can be included in source control)
https://devblogs.microsoft.com/dotnet/asp-net-web-projects-web-debug-config-web-release-config
https://dougrathbone.com/blog/2011/09/14/using-custom-webconfig-transformations-in-msbuild
https://johan.driessen.se/posts/Applying-MSBuild-Config-Transformations-to-any-config-file-without-using-any-Visual-Studio-extensions/
https://www.damirscorner.com/blog/posts/20120108-TransformationOfConfigurationFilesInBuildProcess.html
https://stackoverflow.com/questions/3922291/use-visual-studio-web-config-transform-for-debugging#3994081
https://geoffhudik.com/tech/2010/10/19/webconfig-automation-with-t4-and-a-macro-html/