Fix mixed emit-multi+/- sessions (#18465)

KevinRansom · web-flow · commit abffd375fc32 · 2025-05-05T08:39:55.000-07:00
* Fix mixed emit-multi+/- sessions

* fantomas

* ilverify baseline
diff --git a/docs/release-notes/.FSharp.Compiler.Service/9.0.300.md b/docs/release-notes/.FSharp.Compiler.Service/9.0.300.md
@@ -30,6 +30,7 @@
 * Make `[<CallerMemberName; Struct>]` combination work([PR #18444](https://github.com/dotnet/fsharp/pull/18444/))
 * Fix code completion considers types from own namespace non-imported ([PR #18518](https://github.com/dotnet/fsharp/issues/18518))
 * Code completion: fix getting qualifier expression in do statements in type decls ([PR #18524](https://github.com/dotnet/fsharp/pull/18524))
+* Fixed: [#18441](https://github.com/dotnet/fsharp/issues/18441) FSI multi-emit unstable. ([PR #18465](https://github.com/dotnet/fsharp/pull/18465))
 
 ### Added
 * Added missing type constraints in FCS. ([PR #18241](https://github.com/dotnet/fsharp/pull/18241))
diff --git a/src/Compiler/Interactive/fsi.fs b/src/Compiler/Interactive/fsi.fs
@@ -1673,7 +1673,8 @@ let internal mkBoundValueTypedImpl tcGlobals m moduleName name ty =
     let qname = QualifiedNameOfFile.QualifiedNameOfFile(Ident(moduleName, m))
     entity, v, CheckedImplFile.CheckedImplFile(qname, [], mty, contents, false, false, StampMap.Empty, Map.empty)
 
-let dynamicCcuName = "FSI-ASSEMBLY"
+let dynamicCcuName (isEmitMulti) =
+    $"""FSI-ASSEMBLY{if isEmitMulti then "-MULTI" else ""}"""
 
 /// Encapsulates the coordination of the typechecking, optimization and code generation
 /// components of the F# compiler for interactively executed fragments of code.
@@ -1723,7 +1724,11 @@ type internal FsiDynamicCompiler
             None
         else
             let assemBuilder, moduleBuilder =
-                mkDynamicAssemblyAndModule (dynamicCcuName, tcConfigB.optSettings.LocalOptimizationsEnabled, fsiCollectible)
+                mkDynamicAssemblyAndModule (
+                    dynamicCcuName (tcConfigB.fsiMultiAssemblyEmit),
+                    tcConfigB.optSettings.LocalOptimizationsEnabled,
+                    fsiCollectible
+                )
 
             dynamicAssemblies.Add(assemBuilder)
             Some(assemBuilder, moduleBuilder)
@@ -1813,7 +1818,7 @@ type internal FsiDynamicCompiler
 
             let attrs =
                 [
-                    tcGlobals.MakeInternalsVisibleToAttribute(dynamicCcuName)
+                    tcGlobals.MakeInternalsVisibleToAttribute(dynamicCcuName (tcConfigB.fsiMultiAssemblyEmit))
                     yield! manifest.CustomAttrs.AsList()
                 ]
 
@@ -1960,7 +1965,9 @@ type internal FsiDynamicCompiler
         diagnosticsLogger.AbortOnError(fsiConsoleOutput)
 
         ReportTime tcConfig "Linking"
-        let ilxMainModule = CreateModuleFragment(tcConfigB, dynamicCcuName, codegenResults)
+
+        let ilxMainModule =
+            CreateModuleFragment(tcConfigB, dynamicCcuName (tcConfigB.fsiMultiAssemblyEmit), codegenResults)
 
         diagnosticsLogger.AbortOnError(fsiConsoleOutput)
 
@@ -2652,7 +2659,7 @@ type internal FsiDynamicCompiler
 
         let tcEnv, asms =
             try
-                RequireReferences(ctok, tcImports, tcState.TcEnvFromImpls, dynamicCcuName, resolutions)
+                RequireReferences(ctok, tcImports, tcState.TcEnvFromImpls, dynamicCcuName (tcConfigB.fsiMultiAssemblyEmit), resolutions)
             with _ ->
                 for (path, _, _, m) in refs do
                     tcConfigB.RemoveReferencedAssemblyByPath(m, path)
@@ -3025,7 +3032,7 @@ type internal FsiDynamicCompiler
         let emEnv0 =
             if tcConfigB.fsiMultiAssemblyEmit then
                 let emEnv =
-                    ILMultiInMemoryAssemblyEmitEnv(ilGlobals, resolveAssemblyRef, dynamicCcuName)
+                    ILMultiInMemoryAssemblyEmitEnv(ilGlobals, resolveAssemblyRef, dynamicCcuName (tcConfigB.fsiMultiAssemblyEmit))
 
                 MultipleInMemoryAssemblies emEnv
             else
@@ -3041,10 +3048,10 @@ type internal FsiDynamicCompiler
                 let emEnv = ILDynamicAssemblyWriter.emEnv0
                 SingleRefEmitAssembly(cenv, emEnv)
 
-        let tcEnv, openDecls0 =
-            GetInitialTcEnv(dynamicCcuName, rangeStdin0, tcConfig, tcImports, tcGlobals)
+        let ccuName = dynamicCcuName (tcConfigB.fsiMultiAssemblyEmit)
 
-        let ccuName = dynamicCcuName
+        let tcEnv, openDecls0 =
+            GetInitialTcEnv(ccuName, rangeStdin0, tcConfig, tcImports, tcGlobals)
 
         let tcState =
             GetInitialTcState(rangeStdin0, ccuName, tcConfig, tcGlobals, tcImports, tcEnv, openDecls0)
diff --git a/tests/FSharp.Compiler.ComponentTests/Scripting/Interactive.fs b/tests/FSharp.Compiler.ComponentTests/Scripting/Interactive.fs
@@ -7,6 +7,9 @@ open Xunit
 open System
 open FSharp.Test.Compiler
 open FSharp.Test.ScriptHelpers
+open FSharp.Compiler.Interactive.Shell
+open FSharp.Compiler.Diagnostics
+open FSharp.Test.CompilerAssertHelpers
 
 module ``Interactive tests`` =
 
@@ -35,34 +38,48 @@ module ``Interactive tests`` =
         ]
 
     [<Theory>]
-    [<InlineData(true)>]
-    [<InlineData(false)>]
-    let ``Evaluation of multiple sessions should succeed`` (useMultiEmit) =
+    [<InlineData(true, true)>]
+    [<InlineData(false, false)>]
+    [<InlineData(false, true)>]
+    [<InlineData(true, false)>]
+    let ``Evaluation of multiple sessions should succeed`` (useMultiEmit1, useMultiEmit2) =
 
-        let args : string array = [| if useMultiEmit then "--multiemit+" else "--multiemit-"|]
-        use sessionOne = new FSharpScript(additionalArgs=args)
-        use sessionTwo = new FSharpScript(additionalArgs=args)
+    // This test is to check that we can have multiple sessions and that they can access each other
 
-        sessionOne.Eval("""
-module Test1 =
+        let AssertCanWeAccessTheOtherSession (session: FSharpScript) (script: string) (moduleName: string) (errorChoice: string) =
 
-    let test1 obj = sprintf "Execute - Test1.test1 - %A" obj""") |> ignore
+            let result: Result<FsiValue option, exn> * FSharpDiagnostic[] =  session.Eval(script)
+            let expected =
+                [ (Error 39, Line 1, Col 1, Line 1, Col 6, $"The value, namespace, type or module '{moduleName}' is not defined. Maybe you want one of the following:{errorChoice}") ]
 
-        let result1 = sessionOne.Eval("""Test1.test1 18""") |> getValue
+            match result with
+            | Result.Error _, diagnostics -> Assert.WithDiagnostics(0, diagnostics, expected)
+            | _ -> ()
+
+        // Initialize
+        let args useMultiEmit : string array = [| if useMultiEmit then "--multiemit+" else "--multiemit-"|]
+        use sessionOne = new FSharpScript(additionalArgs = args useMultiEmit1)
+        use sessionTwo = new FSharpScript(additionalArgs = args useMultiEmit2)
+        use sessionThree = new FSharpScript(additionalArgs = args useMultiEmit2)
+
+        // First session
+        sessionOne.Eval("""module Test1 = let test1 obj = sprintf "Execute - Test1.test1 - %A" obj""") |> ignore
+        let result1 = sessionOne.Eval("Test1.test1 18") |> getValue
         let value1 = result1.Value
         Assert.Equal(typeof<string>, value1.ReflectionType)
         Assert.Equal("Execute - Test1.test1 - 18", value1.ReflectionValue :?> string)
 
-        sessionTwo.Eval("""
-module Test2 =
-
-    let test2 obj = sprintf "Execute - Test2.test2 - %A" obj""") |> ignore
-
+        // Second session
+        sessionTwo.Eval("""module Test2 = let test2 obj = sprintf "Execute - Test2.test2 - %A" obj""") |> ignore
         let result2 = sessionTwo.Eval("""Test2.test2 27""") |> getValue
         let value2 = result2.Value
         Assert.Equal(typeof<string>, value2.ReflectionType)
         Assert.Equal("Execute - Test2.test2 - 27", value2.ReflectionValue :?> string)
 
+        // Can I access the other session
+        AssertCanWeAccessTheOtherSession sessionOne "Test2.test2 19" "Test2" "\nTest1\nText"            // Session 1 can't access values from session 2
+        AssertCanWeAccessTheOtherSession sessionTwo "Test1.test1 13" "Test1" "\nTest2\nText"            // Session 2 can't access values from session 1
+
 module ``External FSI tests`` =
     [<Fact>]
     let ``Eval object value``() =
diff --git a/tests/FSharp.Test.Utilities/Compiler.fs b/tests/FSharp.Test.Utilities/Compiler.fs
@@ -1671,20 +1671,47 @@ Actual:
         let private withResultIgnoreNativeRange (expectedResult: ErrorInfo ) (result: CompilationResult) : CompilationResult =
             withResultsIgnoreNativeRange [expectedResult] result
 
-        let withDiagnostics (expected: (ErrorType * Line * Col * Line * Col * string) list) (result: CompilationResult) : CompilationResult =
-            let expectedResults: ErrorInfo list =
-                [ for e in expected do
-                      let (error, Line startLine, Col startCol, Line endLine, Col endCol, message) = e
-                      { Error = error
-                        Range =
-                            { StartLine   = startLine
-                              StartColumn = startCol
-                              EndLine     = endLine
-                              EndColumn   = endCol }
-                        NativeRange = Unchecked.defaultof<_>
-                        SubCategory = ""
-                        Message     = message } ]
-            withResultsIgnoreNativeRange expectedResults result
+        let private convertExpectedsToErrorInfos(expected: (ErrorType * Line * Col * Line * Col * string) list): ErrorInfo list = [
+            for e in expected do
+                let (error, Line startLine, Col startCol, Line endLine, Col endCol, message) = e
+                {
+                    Error = error
+                    Range = {
+                        StartLine   = startLine
+                        StartColumn = startCol
+                        EndLine     = endLine
+                        EndColumn   = endCol
+                    }
+                    NativeRange = Unchecked.defaultof<_>
+                    SubCategory = ""
+                    Message     = message
+                }
+            ]
+
+        let private convertDiagnosticsToErrorInfos (diagnostics: FSharpDiagnostic[]) : ErrorInfo list =
+            diagnostics
+            |> Array.map (fun diagnostic ->
+                let errorType =
+                    match diagnostic.Severity with
+                    | FSharpDiagnosticSeverity.Error -> Error diagnostic.ErrorNumber
+                    | FSharpDiagnosticSeverity.Warning -> Warning diagnostic.ErrorNumber
+                    | FSharpDiagnosticSeverity.Info -> Information diagnostic.ErrorNumber
+                    | FSharpDiagnosticSeverity.Hidden -> Hidden diagnostic.ErrorNumber
+                {
+                    Error = errorType
+                    Range = {
+                        StartLine = diagnostic.StartLine
+                        StartColumn = diagnostic.StartColumn
+                        EndLine = diagnostic.EndLine
+                        EndColumn = diagnostic.EndColumn
+                    }
+                    NativeRange = diagnostic.Range
+                    Message = diagnostic.Message
+                    SubCategory = diagnostic.Subcategory
+                }) |> Array.toList
+
+        let withDiagnostics expected (result: CompilationResult) : CompilationResult =
+            withResultsIgnoreNativeRange (convertExpectedsToErrorInfos expected) result
 
         let withSingleDiagnostic (expected: (ErrorType * Line * Col * Line * Col * string)) (result: CompilationResult) : CompilationResult =
             withDiagnostics [expected] result
@@ -1695,6 +1722,10 @@ Actual:
         let withError (expectedError: ErrorInfo) (result: CompilationResult) : CompilationResult =
             withErrors [expectedError] result
 
+        type Assert =
+            static member WithDiagnostics(libAdjust, result, expected) =
+                assertErrors "Results" libAdjust (convertDiagnosticsToErrorInfos result) (convertExpectedsToErrorInfos expected)
+
         module StructuredResultsAsserts =
             type SimpleErrorInfo =
                 { Error:   ErrorType
diff --git a/tests/FSharp.Test.Utilities/CompilerAssert.fs b/tests/FSharp.Test.Utilities/CompilerAssert.fs
@@ -466,7 +466,7 @@ module CompilerAssertHelpers =
                         yield source.WithFileName(destFileName)
             ]
         rawCompile outputFilePath isExe options targetFramework sources
-    
+
     let assertErrors libAdjust ignoreWarnings (errors: FSharpDiagnostic []) expectedErrors =
         let errorMessage (error: FSharpDiagnostic) =
             let errN, range, message = error.ErrorNumber, error.Range, error.Message
@@ -694,6 +694,9 @@ Updated automatically, please check diffs in your pull request, changes must be
         compileCompilation ignoreWarnings cmpl (fun ((errors, _, _), _) ->
             assertErrors 0 ignoreWarnings errors expectedErrors)
 
+    static member assertWithErrors(libAdjust, ignoreWarnings, errors, expectedErrors) =
+        assertErrors libAdjust, ignoreWarnings, errors, expectedErrors
+
     static member Compile(cmpl: Compilation, ?ignoreWarnings) =
         CompilerAssert.CompileWithErrors(cmpl, [||], defaultArg ignoreWarnings false)
 
diff --git a/tests/ILVerify/ilverify_FSharp.Compiler.Service_Debug_net9.0.bsl b/tests/ILVerify/ilverify_FSharp.Compiler.Service_Debug_net9.0.bsl
@@ -21,7 +21,7 @@
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.CodeAnalysis.Hosted.CompilerHelpers::fscCompile([FSharp.Compiler.Service]FSharp.Compiler.CodeAnalysis.LegacyReferenceResolver, string, string[])][offset 0x00000082][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.CodeAnalysis.Hosted.CompilerHelpers::fscCompile([FSharp.Compiler.Service]FSharp.Compiler.CodeAnalysis.LegacyReferenceResolver, string, string[])][offset 0x0000008B][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.Interactive.Shell+MagicAssemblyResolution::ResolveAssemblyCore([FSharp.Compiler.Service]Internal.Utilities.Library.CompilationThreadToken, [FSharp.Compiler.Service]FSharp.Compiler.Text.Range, [FSharp.Compiler.Service]FSharp.Compiler.CompilerConfig+TcConfigBuilder, [FSharp.Compiler.Service]FSharp.Compiler.CompilerImports+TcImports, [FSharp.Compiler.Service]FSharp.Compiler.Interactive.Shell+FsiDynamicCompiler, [FSharp.Compiler.Service]FSharp.Compiler.Interactive.Shell+FsiConsoleOutput, string)][offset 0x00000015][found Char] Unexpected type on the stack.
-[IL]: Error [StackUnexpected]: : FSharp.Compiler.Interactive.Shell+clo@3502-805::Invoke([S.P.CoreLib]System.Tuple`3<char[],int32,int32>)][offset 0x000001E5][found Char] Unexpected type on the stack.
+[IL]: Error [StackUnexpected]: : FSharp.Compiler.Interactive.Shell+clo@3509-805::Invoke([S.P.CoreLib]System.Tuple`3<char[],int32,int32>)][offset 0x000001E5][found Char] Unexpected type on the stack.
 [IL]: Error [UnmanagedPointer]: : FSharp.Compiler.Interactive.Shell+Utilities+pointerToNativeInt@110::Invoke(object)][offset 0x00000007] Unmanaged pointers are not a verifiable type.
 [IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$FSharpCheckerResults+dataTipOfReferences@2225::Invoke([FSharp.Core]Microsoft.FSharp.Core.Unit)][offset 0x00000084][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$ServiceLexing+clo@921-509::Invoke([FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<System.Tuple`3<FSharp.Compiler.Parser+token,int32,int32>,Microsoft.FSharp.Core.Unit>)][offset 0x00000032][found Char] Unexpected type on the stack.
diff --git a/tests/ILVerify/ilverify_FSharp.Compiler.Service_Debug_netstandard2.0.bsl b/tests/ILVerify/ilverify_FSharp.Compiler.Service_Debug_netstandard2.0.bsl
@@ -28,7 +28,7 @@
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.CodeAnalysis.Hosted.CompilerHelpers::fscCompile([FSharp.Compiler.Service]FSharp.Compiler.CodeAnalysis.LegacyReferenceResolver, string, string[])][offset 0x0000008B][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.Interactive.Shell+FsiStdinSyphon::GetLine(string, int32)][offset 0x00000039][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.Interactive.Shell+MagicAssemblyResolution::ResolveAssemblyCore([FSharp.Compiler.Service]Internal.Utilities.Library.CompilationThreadToken, [FSharp.Compiler.Service]FSharp.Compiler.Text.Range, [FSharp.Compiler.Service]FSharp.Compiler.CompilerConfig+TcConfigBuilder, [FSharp.Compiler.Service]FSharp.Compiler.CompilerImports+TcImports, [FSharp.Compiler.Service]FSharp.Compiler.Interactive.Shell+FsiDynamicCompiler, [FSharp.Compiler.Service]FSharp.Compiler.Interactive.Shell+FsiConsoleOutput, string)][offset 0x00000015][found Char] Unexpected type on the stack.
-[IL]: Error [StackUnexpected]: : FSharp.Compiler.Interactive.Shell+clo@3502-805::Invoke([S.P.CoreLib]System.Tuple`3<char[],int32,int32>)][offset 0x000001E5][found Char] Unexpected type on the stack.
+[IL]: Error [StackUnexpected]: : FSharp.Compiler.Interactive.Shell+clo@3509-805::Invoke([S.P.CoreLib]System.Tuple`3<char[],int32,int32>)][offset 0x000001E5][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.Interactive.Shell+FsiInteractionProcessor::CompletionsForPartialLID([FSharp.Compiler.Service]FSharp.Compiler.Interactive.Shell+FsiDynamicCompilerState, string)][offset 0x0000001B][found Char] Unexpected type on the stack.
 [IL]: Error [UnmanagedPointer]: : FSharp.Compiler.Interactive.Shell+Utilities+pointerToNativeInt@110::Invoke(object)][offset 0x00000007] Unmanaged pointers are not a verifiable type.
 [IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$FSharpCheckerResults+dataTipOfReferences@2225::Invoke([FSharp.Core]Microsoft.FSharp.Core.Unit)][offset 0x00000084][found Char] Unexpected type on the stack.
diff --git a/tests/ILVerify/ilverify_FSharp.Compiler.Service_Release_net9.0.bsl b/tests/ILVerify/ilverify_FSharp.Compiler.Service_Release_net9.0.bsl
@@ -21,7 +21,7 @@
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.CodeAnalysis.Hosted.CompilerHelpers::fscCompile([FSharp.Compiler.Service]FSharp.Compiler.CodeAnalysis.LegacyReferenceResolver, string, string[])][offset 0x00000082][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.CodeAnalysis.Hosted.CompilerHelpers::fscCompile([FSharp.Compiler.Service]FSharp.Compiler.CodeAnalysis.LegacyReferenceResolver, string, string[])][offset 0x0000008B][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.Interactive.Shell+MagicAssemblyResolution::ResolveAssemblyCore([FSharp.Compiler.Service]Internal.Utilities.Library.CompilationThreadToken, [FSharp.Compiler.Service]FSharp.Compiler.Text.Range, [FSharp.Compiler.Service]FSharp.Compiler.CompilerConfig+TcConfigBuilder, [FSharp.Compiler.Service]FSharp.Compiler.CompilerImports+TcImports, [FSharp.Compiler.Service]FSharp.Compiler.Interactive.Shell+FsiDynamicCompiler, [FSharp.Compiler.Service]FSharp.Compiler.Interactive.Shell+FsiConsoleOutput, string)][offset 0x00000015][found Char] Unexpected type on the stack.
-[IL]: Error [StackUnexpected]: : FSharp.Compiler.Interactive.Shell+clo@3502-849::Invoke([S.P.CoreLib]System.Tuple`3<char[],int32,int32>)][offset 0x000001C7][found Char] Unexpected type on the stack.
+[IL]: Error [StackUnexpected]: : FSharp.Compiler.Interactive.Shell+clo@3509-849::Invoke([S.P.CoreLib]System.Tuple`3<char[],int32,int32>)][offset 0x000001C7][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$FSharpCheckerResults+GetReferenceResolutionStructuredToolTipText@2225::Invoke([FSharp.Core]Microsoft.FSharp.Core.Unit)][offset 0x00000076][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$ServiceLexing+clo@921-530::Invoke([FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<System.Tuple`3<FSharp.Compiler.Parser+token,int32,int32>,Microsoft.FSharp.Core.Unit>)][offset 0x00000032][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$ServiceLexing+clo@921-530::Invoke([FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<System.Tuple`3<FSharp.Compiler.Parser+token,int32,int32>,Microsoft.FSharp.Core.Unit>)][offset 0x0000003B][found Char] Unexpected type on the stack.
diff --git a/tests/ILVerify/ilverify_FSharp.Compiler.Service_Release_netstandard2.0.bsl b/tests/ILVerify/ilverify_FSharp.Compiler.Service_Release_netstandard2.0.bsl
