Figure out why CoreCompile was run

why-corecompile.fsx

// This is used to quickly diagnose why a rebuild happened in a large solution
// It reads a binlog file and finds all the CoreCompile targets that were triggered by a file being newer than the output file
// It then prints out the project and the messages that caused the rebuild
// to create a binlog you can refer to https://learn.microsoft.com/en-us/visualstudio/ide/msbuild-logs?view=vs-2022#provide-msbuild-binary-logs-for-investigation
// CLI: dotnet build -bl:mybinlog.binlog
// or in `.build/build.fs` add `BuildParameter.enableBinLog "mybinlog.binlog"` to the `build'` target.

// Use https://msbuildlog.com/ to diagnose further
#r "nuget: MSBuild.StructuredLogger"


open Microsoft.Build.Logging.StructuredLogger

/// Update your binlog path here
let binlog = "path/to/binlog.binlog"

let build = Serialization.Read binlog

let (|Message|_|) (b : BaseNode) =
    match b with
    | :? Message as m -> Some m
    | _ -> None


let causations =
    build
        .FindChildrenRecursive<Target>(fun t ->
            t.Name = "CoreCompile"
            && t.Children
                |> Seq.exists(function Message m ->  m.ToString().Contains "is newer than" | _ -> false)
        )

causations
|> Seq.sortBy(fun t -> t.StartTime)
|> Seq.iter (fun t ->
    printfn $"{t.Project} {t.Name}"
    t.Children
    |> Seq.iter(fun x -> printfn $"  {x}" )
)