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Merged
T-Gro merged 12 commits into from
Aug 24, 2026
Merged

chore(Test): Inhibit RunSynchronouslyImmediate; reduce suite concurrency re #20306 #20308

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6f42291
chore(Test): Inhibit RunSynchronouslyImmedate; reduce suite concurrency
bartelink Aug 21, 2026
153fdb4
chore(Tests): Extend timeout to 30s for CI/heavy load
bartelink Aug 21, 2026
55e0fb4
chore(Build hang triage): Rule out more RSI suspects
bartelink Aug 21, 2026
9fc39e7
fix: formatting
bartelink Aug 21, 2026
ef40c5f
doc: Clarify test collection
bartelink Aug 21, 2026
6abcd1b
cleanup: Remove XUNIT_EXTRAS straggler reference
bartelink Aug 21, 2026
973bc15
refactor: Replace RunTestCasesInSequence with comments
bartelink Aug 21, 2026
0fb4bd5
refactor(RunTestCasesInSequenceAttribute): replace with DisableParall…
bartelink Aug 21, 2026
bab7105
fix: Remove warning build break
bartelink Aug 21, 2026
b1aff55
Roll back compiler temp RunSynchronously use
bartelink Aug 21, 2026
0548a8b
straggler RunTestCasesInSequence -> DisableParallization migrations
bartelink Aug 21, 2026
e841bef
chore(Tests): Reinstate RunSynchronouslyImmediate usage
bartelink Aug 23, 2026
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4 changes: 2 additions & 2 deletions src/Compiler/Driver/fsc.fs
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Expand Up @@ -599,7 +599,7 @@ let main1
// Import basic assemblies
let tcGlobals, frameworkTcImports =
TcImports.BuildFrameworkTcImports(foundationalTcConfigP, sysRes, otherRes)
|> Async.RunSynchronouslyImmediate
|> Async.RunSynchronously // TEMP: NOT Immediate re #20306
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let ilSourceDocs =
[
Expand Down Expand Up @@ -647,7 +647,7 @@ let main1

let tcImports =
TcImports.BuildNonFrameworkTcImports(tcConfigP, frameworkTcImports, otherRes, knownUnresolved, dependencyProvider)
|> Async.RunSynchronouslyImmediate
|> Async.RunSynchronously // TEMP: NOT Immediate re #20306

// register tcImports to be disposed in future
disposables.Register tcImports
Expand Down
2 changes: 1 addition & 1 deletion src/Compiler/Facilities/DiagnosticsLogger.fs
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Expand Up @@ -1019,7 +1019,7 @@ type StackGuard(name: string) =
Thread.CurrentThread.Name <- $"F# Extra Compilation Thread for {name} (depth {depthWhenJump})"
return f ()
}
|> Async.RunSynchronouslyImmediate
|> Async.RunSynchronously // TEMP: NOT Immediate re #20306
finally
depth.Value <- depth.Value - 1

Expand Down
4 changes: 2 additions & 2 deletions src/Compiler/Interactive/fsi.fs
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Expand Up @@ -4802,7 +4802,7 @@ type FsiEvaluationSession
try
let tcConfig = tcConfigP.Get(ctokStartup)

checker.FrameworkImportsCache.Get tcConfig |> Async.RunSynchronouslyImmediate
checker.FrameworkImportsCache.Get tcConfig |> Async.RunSynchronously // TEMP: NOT Immediate re #20306
with e ->
stopProcessingRecovery e range0
failwithf "Error creating evaluation session: %A" e
Expand All @@ -4816,7 +4816,7 @@ type FsiEvaluationSession
unresolvedReferences,
fsiOptions.DependencyProvider
)
|> Async.RunSynchronouslyImmediate
|> Async.RunSynchronously // TEMP: NOT Immediate re #20306
with e ->
stopProcessingRecovery e range0
failwithf "Error creating evaluation session: %A" e
Expand Down
4 changes: 2 additions & 2 deletions ...ComponentTests/Language/BooleanReturningAndReturnTypeDirectedPartialActivePatternTests.fs
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@@ -1,7 +1,7 @@
// Copyright (c) Microsoft Corporation. All Rights Reserved. See License.txt in the project root for license information.

// Because of shared fsi session.
[<FSharp.Test.RunTestCasesInSequence>]
// Leverage caching/prevent concurrent mutation via long-lived fsiSession in module state
[<Xunit.TestClass(DisableParallelization = true)>]
module Language.BooleanReturningAndReturnTypeDirectedPartialActivePatternTests

open Xunit
Expand Down
4 changes: 2 additions & 2 deletions tests/FSharp.Compiler.ComponentTests/Language/SequenceExpressions/SequenceExpressionTests.fs
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Expand Up @@ -7,8 +7,8 @@ open Xunit
open FSharp.Test.Compiler
open FSharp.Test.ScriptHelpers

// Run sequentially because of shared fsiSession.
[<FSharp.Test.RunTestCasesInSequence>]
// Leverage caching/prevent concurrent mutation via long-lived fsiSession in module state
[<TestClass(DisableParallelization = true)>]
module SequenceExpression =

let fsiSession = getSessionForEval [||] LangVersion.Preview
Expand Down
3 changes: 2 additions & 1 deletion tests/FSharp.Compiler.Service.Tests/ErrorList/ScriptDiagnosticsTests.fs
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@@ -1,4 +1,5 @@
[<FSharp.Test.RunTestCasesInSequence>]
// TODO @T-Gro document reasoning for inhibiting parallelization
[<Xunit.TestClass(DisableParallelization = true)>]
module FSharp.Compiler.Service.Tests.ScriptDiagnosticsTests

open System
Expand Down
2 changes: 1 addition & 1 deletion tests/FSharp.Compiler.Service.Tests/FsiTests.fs
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Expand Up @@ -12,7 +12,7 @@ module MyModule =
let test(x: int) = ()

// Running in parallel is unstable with occasional System.IO.FileLoadException: Could not load file or assembly 'FSI-ASSEMBLY...
[<RunTestCasesInSequence>]
[<TestClass(DisableParallelization = true)>]
module FsiTests =

let createFsiSession (useOneDynamicAssembly: bool) =
Expand Down
4 changes: 2 additions & 2 deletions tests/FSharp.Compiler.Service.Tests/ModuleReaderCancellationTests.fs
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@@ -1,5 +1,5 @@
// Sequential execution because of shared mutable state.
[<FSharp.Test.RunTestCasesInSequence>]
// Tests utilize caching in module state (checker) and `mutable` state
[<Xunit.TestClass(DisableParallelization = true)>]
module FSharp.Compiler.Service.Tests.ModuleReaderCancellationTests

open System
Expand Down
3 changes: 1 addition & 2 deletions tests/FSharp.Compiler.Service.Tests/MultiProjectAnalysisTests.fs
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Expand Up @@ -910,8 +910,7 @@ module GenerativeTypeProviderFallbackTest =
begin
let fileName = __SOURCE_DIRECTORY__ ++ @"../service/data/TestProject/TestProject.fs"
let fileSource = FileSystem.OpenFileForReadShim(fileName).ReadAllText()
let fileParseResults, fileCheckAnswer = checker.ParseAndCheckFileInProject(fileName, 0, SourceText.ofString fileSource, optionsTestProject) |> Async.
RunSynchronouslyImmediate
let fileParseResults, fileCheckAnswer = checker.ParseAndCheckFileInProject(fileName, 0, SourceText.ofString fileSource, optionsTestProject) |> Async.RunSynchronouslyImmediate

let fileCheckResults =
match fileCheckAnswer with
Expand Down
23 changes: 8 additions & 15 deletions tests/FSharp.Compiler.Service.Tests/ProjectAnalysisTests.fs
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Expand Up @@ -574,7 +574,6 @@ let ``Test file explicit parse symbols`` () =

let wholeProjectResults = checker.ParseAndCheckProject(Project1.options) |> Async.RunSynchronouslyImmediate
let parseResults1 = checker.ParseFile(Project1.fileName1, Project1.fileSource1, Project1.parsingOptions) |> Async.RunSynchronouslyImmediate

let parseResults2 = checker.ParseFile(Project1.fileName2, Project1.fileSource2, Project1.parsingOptions) |> Async.RunSynchronouslyImmediate

let checkResults1 =
Expand Down Expand Up @@ -621,7 +620,6 @@ let ``Test file explicit parse all symbols`` () =

let wholeProjectResults = checker.ParseAndCheckProject(Project1.options) |> Async.RunSynchronouslyImmediate
let parseResults1 = checker.ParseFile(Project1.fileName1, Project1.fileSource1, Project1.parsingOptions) |> Async.RunSynchronouslyImmediate

let parseResults2 = checker.ParseFile(Project1.fileName2, Project1.fileSource2, Project1.parsingOptions) |> Async.RunSynchronouslyImmediate

let checkResults1 =
Expand Down Expand Up @@ -3721,7 +3719,7 @@ let _ = MyType().DoNothing()
{ checker.GetProjectOptionsFromCommandLineArgs(projFileName, args) with SourceFiles = fileNames })

// Uses TestTP (built locally) — no NuGet needed, deterministic.
[<Fact; RunTestCasesInSequence>]
[<Fact4(DisableParallelization = true)>] // Inhibit shared usage of Project25.checker module state
let ``Test Project25 whole project errors`` () =
let wholeProjectResults = Project25.checker.ParseAndCheckProject(Project25.options.Value) |> Async.RunSynchronouslyImmediate

Expand All @@ -3730,7 +3728,7 @@ let ``Test Project25 whole project errors`` () =

wholeProjectResults.Diagnostics.Length |> shouldEqual 0

[<Fact; RunTestCasesInSequence>]
[<Fact4(DisableParallelization = true)>] // Inhibit shared usage of Project25.checker module state
let ``Test Project25 symbol uses of type-provided members`` () =
let wholeProjectResults = Project25.checker.ParseAndCheckProject(Project25.options.Value) |> Async.RunSynchronouslyImmediate

Expand Down Expand Up @@ -3789,7 +3787,7 @@ let ``Test Project25 symbol uses of type-provided members`` () =
[| ("file1", ((5, 8), (5, 21))) // line 5: T().DoNothing
("file1", ((10, 8), (10, 26))) |] // line 10: MyType().DoNothing

[<Fact; RunTestCasesInSequence>]
[<Fact4(DisableParallelization = true)>] // Inhibit shared usage of Project25.checker module state
let ``GetDeclarationLocation on a provided-ctor without DefinitionLocationAttribute returns DeclFound (regression #5538)`` () =
let wholeProjectResults =
Project25.checker.ParseAndCheckProject(Project25.options.Value)
Expand Down Expand Up @@ -3830,7 +3828,7 @@ let ``GetDeclarationLocation on a provided-ctor without DefinitionLocationAttrib
| FindDeclResult.ExternalDecl _ ->
failwith "expected DeclFound for provided-ctor `T()`, got ExternalDecl"

[<Fact; RunTestCasesInSequence>]
[<Fact>]
let ``GetDeclarationLocation on a provided-ctor invoked through the original provided name returns DeclFound (regression #5538)`` () =
let wholeProjectResults =
Project25.checker.ParseAndCheckProject(Project25.options.Value)
Expand Down Expand Up @@ -3867,7 +3865,7 @@ let ``GetDeclarationLocation on a provided-ctor invoked through the original pro
| FindDeclResult.ExternalDecl _ ->
failwith "expected DeclFound for provided-ctor `MyType()`, got ExternalDecl"

[<Fact; RunTestCasesInSequence>]
[<Fact>]
let ``Test Project25 symbol uses of type-provided types`` () =
let wholeProjectResults = Project25.checker.ParseAndCheckProject(Project25.options.Value) |> Async.RunSynchronouslyImmediate

Expand All @@ -3890,7 +3888,7 @@ let ``Test Project25 symbol uses of type-provided types`` () =
("file1", ((5, 8), (5, 9))) // line 5: let _ = >T<() (T resolves to MyType)
("file1", ((10, 8), (10, 14))) |] // line 10: let _ = >MyType<()

[<Fact; RunTestCasesInSequence>]
[<Fact>]
let ``Test Project25 symbol uses of fully-qualified records`` () =
let wholeProjectResults = Project25.checker.ParseAndCheckProject(Project25.options.Value) |> Async.RunSynchronouslyImmediate

Expand Down Expand Up @@ -4884,7 +4882,6 @@ let ``Test project37 typeof and arrays in attribute constructor arguments`` () =
let wholeProjectResults =
checker.ParseAndCheckProject(Project37.options)
|> Async.RunSynchronouslyImmediate

let allSymbolsUses = wholeProjectResults.GetAllUsesOfAllSymbols()
for su in allSymbolsUses do
match su.Symbol with
Expand Down Expand Up @@ -4939,7 +4936,6 @@ let ``Test project37 DeclaringEntity`` () =
let wholeProjectResults =
checker.ParseAndCheckProject(Project37.options)
|> Async.RunSynchronouslyImmediate

let allSymbolsUses = wholeProjectResults.GetAllUsesOfAllSymbols()
for sym in allSymbolsUses do
match sym.Symbol with
Expand Down Expand Up @@ -5028,7 +5024,6 @@ let ``Test project38 abstract slot information`` () =
let wholeProjectResults =
checker.ParseAndCheckProject(Project38.options)
|> Async.RunSynchronouslyImmediate

let printAbstractSignature (s: FSharpAbstractSignature) =
let printType (t: FSharpType) =
hash t |> ignore // smoke test to check hash code doesn't loop
Expand Down Expand Up @@ -5358,7 +5353,6 @@ let ``Test project42 to ensure cached checked results are invalidated`` () =
FileSystem.OpenFileForWriteShim(Project42.fileName1).Write("""module File1""")
try
let checkedFile2Again = checker.ParseAndCheckFileInProject(Project42.fileName2, text2.GetHashCode(), text2, Project42.options) |> Async.RunSynchronouslyImmediate

match checkedFile2Again with
| _, FSharpCheckFileAnswer.Succeeded(checkedFile2AgainResults) ->
Assert.NotEmpty(checkedFile2AgainResults.Diagnostics) // this should contain errors as File1 does not contain the function `test()`
Expand Down Expand Up @@ -5473,7 +5467,7 @@ let x = (1 = 3.0)
let args = mkProjectCommandLineArgs (dllName, [])
let options = { checker.GetProjectOptionsFromCommandLineArgs (projFileName, args) with SourceFiles = fileNames }

[<Fact; RunTestCasesInSequence>]
[<Fact4(DisableParallelization = true)>] // Avoid concurrent use of checker
let ``Test diagnostics with line directives active`` () =

let wholeProjectResults = checker.ParseAndCheckProject(ProjectLineDirectives.options) |> Async.RunSynchronouslyImmediate
Expand All @@ -5491,7 +5485,7 @@ let ``Test diagnostics with line directives active`` () =
let m = e.Range in m.StartLine, m.EndLine, m.FileName ]
|> shouldEqual [10, 10, "Test.fsy"]

[<Fact; RunTestCasesInSequence>]
[<Fact4(DisableParallelization = true)>] // Avoid concurrent use of checker
let ``Test diagnostics with line directives ignored`` () =

// If you pass hidden IDE flag --ignorelinedirectives, the diagnostics are reported w.r.t. the source
Expand Down Expand Up @@ -5900,7 +5894,6 @@ let checkContentAsScript content =
let scriptFullPath = Path.Combine(tempDir, scriptName)
let sourceText = SourceText.ofString content
let projectOptions, _ = checker.GetProjectOptionsFromScript(scriptFullPath, sourceText, useSdkRefs = true, assumeDotNetFramework = false) |> Async.RunSynchronouslyImmediate

let parseOptions, _ = checker.GetParsingOptionsFromProjectOptions projectOptions
let parseResults = checker.ParseFile(scriptFullPath, sourceText, parseOptions) |> Async.RunSynchronouslyImmediate
let checkResults = checker.CheckFileInProject(parseResults, scriptFullPath, 0, sourceText, projectOptions) |> Async.RunSynchronouslyImmediate
Expand Down
4 changes: 2 additions & 2 deletions tests/FSharp.Compiler.Service.Tests/ScriptOptionsTests.fs
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@@ -1,5 +1,5 @@
// Because of script closure cache.
[<FSharp.Test.RunTestCasesInSequence>]
// Avoid parallelism to leverage script closure cache.
[<Xunit.TestClass(DisableParallelization = true)>]
module FSharp.Compiler.Service.Tests.ScriptOptionsTests

open Xunit
Expand Down
9 changes: 7 additions & 2 deletions tests/FSharp.Core.UnitTests/FSharp.Core/Microsoft.FSharp.Control/AsyncModuleFunctions.fs
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@@ -1,7 +1,10 @@
// Copyright (c) Microsoft Corporation. All Rights Reserved. See License.txt in the project root for license information.

// Tests for camelCase functions in module Async
module FSharp.Core.UnitTests.Controa.AsyncModuleFunctionsTestsl

// Intentionally in same collection to help rule out potential flakiness due to concurrency re #20306
[<Xunit.Collection(nameof FSharp.Test.NotThreadSafeResourceCollection)>]
module FSharp.Core.UnitTests.Control.AsyncModuleFunctionsTests

open System
open System.Threading
Expand All @@ -19,7 +22,9 @@ let cancelWithToken (tcs: TaskCompletionSource<'T>) =
ct
#endif

let asyncWait (a: Async<'T>): 'T = Async.RunSynchronouslyImmediate a
// TEMP disabled Immediate re #20306 // let asyncWait (a: Async<'T>): 'T = Async.RunSynchronouslyImmediate a
// TEMP disabled Immediate re #20306 // let asyncWaitWithCt (ct: CancellationToken) (a: Async<'T>): 'T = Async.RunSynchronouslyImmediate(a, cancellationToken = ct)
let asyncWait (a: Async<'T>): 'T = Async.RunSynchronously a
let asyncWaitWithCt (ct: CancellationToken) (a: Async<'T>): 'T = Async.RunSynchronously(a, cancellationToken = ct)

[<Fact>]
Expand Down
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