fire events when script host resolves assembly reference (#7571)

* add event every time `#r` is invoked

* pass additional args to script host

Author: brettfo

src/fsharp/CompileOps.fs

@@ -4775,7 +4775,7 @@ and [<Sealed>] TcImports(tcConfigP: TcConfigProvider, initialResolutions: TcAsse
 
 /// Process #r in F# Interactive.
 /// Adds the reference to the tcImports and add the ccu to the type checking environment.
-let RequireDLL (ctok, tcImports: TcImports, tcEnv, thisAssemblyName, m, file) = 
+let RequireDLL (ctok, tcImports: TcImports, tcEnv, thisAssemblyName, m, file, assemblyReferenceAdded: string -> unit) =
     let resolutions = CommitOperationResult(tcImports.TryResolveAssemblyReference(ctok, AssemblyReference(m, file, None), ResolveAssemblyReferenceMode.ReportErrors))
     let dllinfos, ccuinfos = tcImports.RegisterAndImportReferencedAssemblies(ctok, resolutions) |> Cancellable.runWithoutCancellation
 
@@ -4786,7 +4786,13 @@ let RequireDLL (ctok, tcImports: TcImports, tcEnv, thisAssemblyName, m, file) =
 
     let g = tcImports.GetTcGlobals()
     let amap = tcImports.GetImportMap()
-    let tcEnv = (tcEnv, asms) ||> List.fold (fun tcEnv asm -> AddCcuToTcEnv(g, amap, m, tcEnv, thisAssemblyName, asm.FSharpViewOfMetadata, asm.AssemblyAutoOpenAttributes, asm.AssemblyInternalsVisibleToAttributes)) 
+    let buildTcEnv tcEnv asm =
+        let tcEnv = AddCcuToTcEnv(g, amap, m, tcEnv, thisAssemblyName, asm.FSharpViewOfMetadata, asm.AssemblyAutoOpenAttributes, asm.AssemblyInternalsVisibleToAttributes)
+        match asm.FSharpViewOfMetadata.FileName with
+        | Some asmPath -> assemblyReferenceAdded asmPath
+        | None -> ()
+        tcEnv
+    let tcEnv = (tcEnv, asms) ||> List.fold buildTcEnv
     tcEnv, (dllinfos, asms)
 
 

src/fsharp/CompileOps.fsi

@@ -672,7 +672,7 @@ val WriteOptimizationData: TcGlobals * filename: string * inMem: bool * CcuThunk
 
 /// Process #r in F# Interactive.
 /// Adds the reference to the tcImports and add the ccu to the type checking environment.
-val RequireDLL: CompilationThreadToken * TcImports * TcEnv * thisAssemblyName: string * referenceRange: range * file: string -> TcEnv * (ImportedBinary list * ImportedAssembly list)
+val RequireDLL: CompilationThreadToken * TcImports * TcEnv * thisAssemblyName: string * referenceRange: range * file: string * assemblyReferenceAdded: (string -> unit) -> TcEnv * (ImportedBinary list * ImportedAssembly list)
 
 /// Processing # commands
 val ProcessMetaCommandsFromInput: 

src/fsharp/FSharp.Compiler.Private.Scripting/FSharpScript.fs

@@ -5,7 +5,7 @@ namespace FSharp.Compiler.Scripting
 open System
 open FSharp.Compiler.Interactive.Shell
 
-type FSharpScript(?captureInput: bool, ?captureOutput: bool) as this =
+type FSharpScript(?captureInput: bool, ?captureOutput: bool, ?additionalArgs: string[]) as this =
     let outputProduced = Event<string>()
     let errorProduced = Event<string>()
 
@@ -17,6 +17,7 @@ type FSharpScript(?captureInput: bool, ?captureOutput: bool) as this =
     do stderr.LineWritten.Add errorProduced.Trigger
     let captureInput = defaultArg captureInput false
     let captureOutput = defaultArg captureOutput false
+    let additionalArgs = defaultArg additionalArgs [||]
     let savedInput = Console.In
     let savedOutput = Console.Out
     let savedError = Console.Error
@@ -29,9 +30,12 @@ type FSharpScript(?captureInput: bool, ?captureOutput: bool) as this =
         ())()
 
     let config = FsiEvaluationSession.GetDefaultConfiguration()
-    let argv = [| this.GetType().Assembly.Location; "--noninteractive"; "--targetprofile:netcore"; "--quiet" |]
+    let baseArgs = [| this.GetType().Assembly.Location; "--noninteractive"; "--targetprofile:netcore"; "--quiet" |]
+    let argv = Array.append baseArgs additionalArgs
     let fsi = FsiEvaluationSession.Create (config, argv, stdin, stdout, stderr, collectible=true)
 
+    member __.AssemblyReferenceAdded = fsi.AssemblyReferenceAdded
+
     member __.ProvideInput = stdin.ProvideInput
 
     member __.OutputProduced = outputProduced.Publish

src/fsharp/fsi/fsi.fs

@@ -962,6 +962,8 @@ type internal FsiDynamicCompiler
     let outfile = "TMPFSCI.exe"
     let assemblyName = "FSI-ASSEMBLY"
 
+    let assemblyReferenceAddedEvent = Control.Event<string>()
+
     let mutable fragmentId = 0
     let mutable prevIt : ValRef option = None
 
@@ -1245,7 +1247,7 @@ type internal FsiDynamicCompiler
         let tcState = istate.tcState 
         let tcEnv,(_dllinfos,ccuinfos) = 
             try
-                RequireDLL (ctok, tcImports, tcState.TcEnvFromImpls, assemblyName, m, path)
+                RequireDLL (ctok, tcImports, tcState.TcEnvFromImpls, assemblyName, m, path, assemblyReferenceAddedEvent.Trigger)
             with e ->
                 tcConfigB.RemoveReferencedAssemblyByPath(m,path)
                 reraise()
@@ -1334,6 +1336,8 @@ type internal FsiDynamicCompiler
     member __.FormatValue(obj:obj, objTy) = 
         valuePrinter.FormatValue(obj, objTy)
 
+    member __.AssemblyReferenceAdded = assemblyReferenceAddedEvent.Publish
+
 //----------------------------------------------------------------------------
 // ctrl-c handling
 //----------------------------------------------------------------------------
@@ -2640,6 +2644,9 @@ type FsiEvaluationSession (fsi: FsiEvaluationSessionHostConfig, argv:string[], i
         fsiInteractionProcessor.EvalScript(ctok, scriptPath, errorLogger)
         |> commitResultNonThrowing errorOptions scriptPath errorLogger
         |> function Choice1Of2 (_), errs -> Choice1Of2 (), errs | Choice2Of2 exn, errs -> Choice2Of2 exn, errs
+
+    /// Event fires every time an assembly reference is added to the execution environment, e.g., via `#r`.
+    member __.AssemblyReferenceAdded = fsiDynamicCompiler.AssemblyReferenceAdded
 
     /// Performs these steps:
     ///    - Load the dummy interaction, if any

src/fsharp/fsi/fsi.fsi

@@ -227,6 +227,9 @@ type FsiEvaluationSession =
     /// A host calls this to report an unhandled exception in a standard way, e.g. an exception on the GUI thread gets printed to stderr
     member ReportUnhandledException : exn: exn -> unit
 
+    /// Event fires every time an assembly reference is added to the execution environment, e.g., via `#r`.
+    member AssemblyReferenceAdded : IEvent<string>
+
     /// Load the dummy interaction, load the initial files, and,
     /// if interacting, start the background thread to read the standard input.
     ///

tests/FSharp.Compiler.Private.Scripting.UnitTests/FSharpScriptTests.fs

@@ -3,6 +3,7 @@
 namespace FSharp.Compiler.Scripting.UnitTests
 
 open System
+open System.IO
 open System.Threading
 open FSharp.Compiler.Interactive.Shell
 open FSharp.Compiler.Scripting
@@ -57,3 +58,27 @@ type InteractiveTests() =
         let value = opt.Value
         Assert.AreEqual(typeof<int>, value.ReflectionType)
         Assert.AreEqual(5, value.ReflectionValue :?> int)
+
+    [<Test>]
+    member __.``Assembly reference event successful``() =
+        use script = new FSharpScript()
+        let testAssembly = "System.dll"
+        let mutable assemblyResolveEventCount = 0
+        let mutable foundAssemblyReference = false
+        Event.add (fun (assembly: string) ->
+            assemblyResolveEventCount <- assemblyResolveEventCount + 1
+            foundAssemblyReference <- String.Compare(testAssembly, Path.GetFileName(assembly), StringComparison.OrdinalIgnoreCase) = 0)
+            script.AssemblyReferenceAdded
+        script.Eval(sprintf "#r \"%s\"" testAssembly) |> ignoreValue
+        Assert.AreEqual(1, assemblyResolveEventCount)
+        Assert.True(foundAssemblyReference)
+
+    [<Test>]
+    member __.``Assembly reference event unsuccessful``() =
+        use script = new FSharpScript()
+        let testAssembly = "not-an-assembly-that-can-be-found.dll"
+        let mutable foundAssemblyReference = false
+        Event.add (fun _ -> foundAssemblyReference <- true) script.AssemblyReferenceAdded
+        let _result, errors = script.Eval(sprintf "#r \"%s\"" testAssembly)
+        Assert.AreEqual(1, errors.Length)
+        Assert.False(foundAssemblyReference)