IdentityModel file version revision differs due to `DateTime.Now`-based formula

[mthalman]

The IdentityModel DLLs have a FileVersion revision that is computed from the current date/time, causing it to always differ between builds:

• MSFT: FileVersion:8.0.1.50722
• SB: FileVersion:8.0.0.64245

(Note: the 8.0.0 vs 8.0.1 base difference is #5508; this issue is about the 50722 vs 64245 revision.)

The IdentityModel repo's build/common.props computes the FileVersion revision using a DateTime.Now-based formula:

<FileVersion Condition="'$(WilsonVersion)' != '' and '$(IsCustomPreview)' != 'true'">
    $(WilsonVersion).$([System.DateTime]::Now.AddYears(-2019).Year)$([System.DateTime]::Now.ToString("MMdd"))</FileVersion>

The revision is {yearsSince2019}{MMdd}, so a build on July 22 of year 5 (2024) produces 50722, while a build on a different date produces a different value. This is inherently non-deterministic — even if Category 3's base version issue were fixed, the revision would still differ between the MSFT and SB builds.

Affected DLLs

• Microsoft.IdentityModel.Abstractions.dll
• Microsoft.IdentityModel.JsonWebTokens.dll
• Microsoft.IdentityModel.Logging.dll
• Microsoft.IdentityModel.Tokens.dll
• System.IdentityModel.Tokens.Jwt.dll

[mthalman]

Logged an issue for upstream to make this better: AzureAD/azure-activedirectory-identitymodel-extensions-for-dotnet#3440