Add a check for SemVer compliance to the build

fcs/build.fsx

@@ -6,6 +6,7 @@
 
 open System
 open System.IO
+open Paket
 open Fake.BuildServer
 open Fake.Core
 open Fake.DotNet
@@ -111,9 +112,59 @@ Target.create "PublishNuGet" (fun _ ->
   )
 )
 
+let anchor (path: string) =
+  System.IO.Path.GetFullPath(Path.Combine(__SOURCE_DIRECTORY__, path))
+
+let bumpMajor (semver: Paket.SemVerInfo) =
+  { semver with Major = semver.Major + 1u
+                Minor = 0u
+                Patch = 0u }
+
+let bumpMinor (semver: Paket.SemVerInfo) =
+  { semver with Minor = semver.Minor + 1u
+                Patch = 0u }
+
+let bumpPatch (semver: Paket.SemVerInfo) =
+  { semver with Patch = semver.Patch + 1u }
+
+let (|WithinRange|OutsideRange|) (leftSemver, (magnitude: SynVer.Version), rightSemver) =
+  let allowedMin =
+    match magnitude with
+    | SynVer.Version.Major -> bumpMajor leftSemver
+    | SynVer.Version.Minor -> bumpMinor leftSemver
+    | SynVer.Version.Patch -> bumpPatch leftSemver
+
+  if rightSemver < allowedMin || rightSemver < leftSemver then OutsideRange else WithinRange
+
+Target.create "ValidateVersionBump" (fun _ ->
+  let intendedVersion = Paket.PublicAPI.ParseSemVer release.NugetVersion
+  let lockfile = Paket.LockFile.LoadFrom "paket.lock"
+  let refGroup = lockfile.Groups.[Paket.Domain.GroupName "reference"]
+  let oldPackage = refGroup.Resolution.[Paket.Domain.PackageName "FSharp.Compiler.Service"]
+  let oldVersion = oldPackage.Version
+  let oldSurfaceArea = SynVer.SurfaceArea.ofAssembly (System.Reflection.Assembly.LoadFile (anchor "packages/reference/FSharp.Compiler.Service/lib/netstandard2.0/FSharp.Compiler.Service.dll"))
+  let newSurfaceArea = SynVer.SurfaceArea.ofAssembly (System.Reflection.Assembly.LoadFile (anchor "../artifacts/bin/fcs/Release/netstandard2.0/FSharp.Compiler.Service.dll"))
+  let (computedVersion, computedMagnitude) = SynVer.SurfaceArea.bump (string oldVersion) oldSurfaceArea newSurfaceArea
+  let parsedComputedVersion = Paket.PublicAPI.ParseSemVer computedVersion
+  let apiDiffs = SynVer.SurfaceArea.diff oldSurfaceArea newSurfaceArea |> String.concat "\n"
+  match oldVersion, computedMagnitude, intendedVersion with
+  | WithinRange ->
+    Trace.tracefn "Version %A is within the allowed range of %A from the prior version of %A" intendedVersion computedMagnitude oldVersion
+  | OutsideRange ->
+    failwithf """Version bump invalid.
+  Version packaged was %A
+  Version computed due to API diffs was %A
+  Allowed version magnitude change is %A
+  The full set of API diffs is:
+%A
+"""  intendedVersion parsedComputedVersion computedMagnitude apiDiffs
+)
+
 // --------------------------------------------------------------------------------------
 // Run all targets by default. Invoke 'build <Target>' to override
 
+
+
 Target.create "Start" ignore
 Target.create "Release" ignore
 Target.create "GenerateDocs" ignore
@@ -140,6 +191,7 @@ open Fake.Core.TargetOperators
 
 "Build"
   ==> "NuGet"
+  ==> "ValidateVersionBump"
   ==> "PublishNuGet"
   ==> "Release"
 

fcs/paket.dependencies

@@ -15,6 +15,8 @@ nuget Fake.Core.UserInput
 nuget Fake.DotNet.Cli
 nuget Fake.DotNet.Fsi
 nuget Fake.DotNet.Paket
+nuget SynVer.FAKE
+nuget Paket.Core
 
 group generate
 
@@ -27,4 +29,12 @@ nuget Fake.Core
 nuget Fake.IO.FileSystem
 nuget Fake.Core.Trace
 nuget FSharp.Literate 4.0.0-alpha03
-nuget FSharp.Formatting 4.0.0-alpha03
+nuget FSharp.Formatting 4.0.0-alpha03
+
+group reference
+
+source https://api.nuget.org/v3/index.json
+framework: netstandard2.0
+
+storage: packages
+nuget FSharp.Compiler.Service 34.1.0