CompileAssemblyFromFile crashes with "The system cannot find the file specified" even though File.Exists reports that the file exists

[sharma7n]

Description

When I call CompileAssemblyFromFile on my provider instance, the program throws the following error stack trace:

Unhandled Exception: System.ComponentModel.Win32Exception: The system cannot find the file specified
   at System.Diagnostics.Process.StartWithCreateProcess(ProcessStartInfo startInfo)
   at FSharp.Compiler.CodeDom.Internal.Compiler.compileFiles(String args, CompilerResults res)
   at FSharp.Compiler.CodeDom.Internal.Compiler.compileAssemblyFromFileBatch(CompilerParameters options, String[] fileNames, CompilerResults results, FSharpFunc`2 sortf)
   at Program.main(String[] argv)

This occurs despite the fact that System.IO.File.Exists returns true when passed in the file path.

Here is the full code:

open System.IO
open System.CodeDom.Compiler
open FSharp.Compiler.CodeDom

[<EntryPoint>]
let main argv =
    let sourceFilePath = Array.get argv 0
    if File.Exists(sourceFilePath) then
        let provider = new FSharpCodeProvider()
        let mutable compilerParameters = CompilerParameters()
        compilerParameters.GenerateInMemory <- true
        provider.CompileAssemblyFromFile(compilerParameters, [| sourceFilePath |])
        |> ignore
    else
        printf "File does not exist"
    0

Here is myfsproj file:

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net461</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <Compile Include="Program.fs" />
  </ItemGroup>

  <ItemGroup>
    <PackageReference Include="FSharp.Compiler.CodeDom" Version="1.0.0.1" />
  </ItemGroup>

</Project>

Repro steps

1. Create a new application using: dotnet new console -lang F#.
2. cd into the application directory.
3. Paste the above code block into Program.fs.
4. Paste the above config block into <application>.fsproj.
5. dotnet build (succeeds).
6. Create an F# source file in the same directory and save it as foo.fs. I used the following:

namespace Foo

type Bar = { baz : int }

7. dotnet run foo.fs

Expected behavior

The program executes without throwing an exception.

Actual behavior

The program throws System.ComponentModel.Win32Exception with the above stack trace.

Known workarounds

No known workarounds.

Related information

• Operating system: Windows 10, 64-bit OS, x64-based processor
• Branch: Hopefully master? (installed from nuget)
• .NET Runtime, CoreCLR or Mono Version: dotnet --version returns '3.0.100'

[drvink]

Sorry I'm so late in replying to this. May I ask how you're using this package with .NET Core? FCS is a better, well-supported option for F#; this package really exists for legacy compatibility at this point...

[sharma7n]

Unfortunately, I'm no longer working at the company where I was trying to do this and no longer have access to the machine I was developing on, so I can't answer your question. I'll just go ahead and close the issue. Thanks!