PEverify issues using 2.10.0+ NuGet versions of OpenXml

[Szaamaan]

Description

OpenXML NuGet libraries with version 2.10.0 and upwards fail PEverify.

Information

• DocumentFormat.OpenXml Version: 2.10.0 and upwards
• Microsoft (R) .NET Framework PE Verifier. Version 4.0.30319.0

Repro

Run PEverify (available in Developer Command Prompt for VS, I'm using 2019 version) on DocumentFormat.OpenXML.dll

Observed

peverify DocumentFormat.OpenXml.dll

Microsoft (R) .NET Framework PE Verifier.  Version  4.0.30319.0
Copyright (c) Microsoft Corporation.  All rights reserved.

[IL]: Error: [C:\Project\bin\Debug\DocumentFormat.OpenXml.dll : DocumentFormat.OpenXml.Framework.ElementPropertyCollection`1[T]::get_Length][offset 0x00000001] Cannot change initonly field outside its .ctor.
[IL]: Error: [C:\Project\bin\Debug\DocumentFormat.OpenXml.dll : DocumentFormat.OpenXml.Framework.ElementPropertyCollection`1[T]::GetIndex][offset 0x00000044] Cannot change initonly field outside its .ctor.
[IL]: Error: [C:\Project\bin\Debug\DocumentFormat.OpenXml.dll : DocumentFormat.OpenXml.Framework.ValidatorCollection::GetEnumerator][offset 0x00000001] Cannot change initonly field outside its .ctor.
[IL]: Error: [C:\Project\bin\Debug\DocumentFormat.OpenXml.dll : DocumentFormat.OpenXml.Framework.ElementPropertyCollection`1+Enumerator[T]::get_Current][offset 0x00000001] Cannot change initonly field outside its .ctor.
[IL]: Error: [C:\Project\bin\Debug\DocumentFormat.OpenXml.dll : DocumentFormat.OpenXml.Framework.ElementPropertyCollection`1+Enumerator[T]::MoveNext][offset 0x00000012] Cannot change initonly field outside its .ctor.
[IL]: Error: [C:\Project\bin\Debug\DocumentFormat.OpenXml.dll : DocumentFormat.OpenXml.Framework.ElementPropertyCollection`1+PropertyEntry[T]::get_Property][offset 0x00000001] Cannot change initonly field outside its .ctor.
[IL]: Error: [C:\Project\bin\Debug\DocumentFormat.OpenXml.dll : DocumentFormat.OpenXml.Framework.ElementPropertyCollection`1+PropertyEntry[T]::get_Value][offset 0x00000001] Cannot change initonly field outside its .ctor.
[IL]: Error: [C:\Project\bin\Debug\DocumentFormat.OpenXml.dll : DocumentFormat.OpenXml.Framework.ElementPropertyCollection`1+PropertyEntry[T]::SetValue][offset 0x00000001] Cannot change initonly field outside its .ctor.
8 Error(s) Verifying DocumentFormat.OpenXml.dll

While the library works fine in simple console applications / libraries, I found it will fail to work when ILmerged into MS CRM Sandbox (which is running on partial trust towards external DLLs), which is what led me to check the DLL using PEverify. Previous version (2.9.1 and earlier) don't have PEverify errors and their usage in MS CRM Sandbox doesn't cause issues.

Expected

PEverify should not show any errors. DLL should be usable after ILmerge in MS CRM Sandbox (partial trust env).

[twsouthwick]

@Szaamaan thanks for the issue. This is due to using readonly structs internally. Appears there was an issue discussing this dotnet/roslyn#22485.

It appears this can cause issues in partial trust so apparently it's a breaking change. What framework version are you running? I'll add the compat flag to .NET Framework builds (partial trust doesn't exist on Core so standard versions don't need it)

[Szaamaan]

I was using .NET 4.6.2 (I think; might have been 4.5.2). As per the description, I was having issues actually getting the DLL to run in MS CRM Sandbox after using ILMerge to make a single library (common way of getting external libraries when creating MS CRM plugins), so I'm not 100% clear if the specific framework version I was using matters or if it's more of an issue with ILmerge not working fine with these PEverify issues.

[twsouthwick]

Yes, it matters, as we also support .NET Core, etc and just wanted to make sure this is only on .NET Framework. I have a fix for this to ensure compat with PEVerify on framework builds.

[twsouthwick]

According to the Roslyn bug, this can be hit in partial trust. ILMerge is kind of best effort and can cause it's own bugs that we're probably not in a place to fully test. If this is due to ILMerge, we'd need to look down a different path. However, the errors you're seeing are also visible without IL merge, so once the merge is in, you can grab the CI build and give it a try.

[twsouthwick]

@Szaamaan Can you verify that your process works with the latest builds that have peverify compat enabled? Use the CI feed described in the README, and you'll need at least v2.11.1-ci0007

[Szaamaan]

@twsouthwick The CI version you linked works fine in an MS CRM Sandbox (partial trust) after ILmerging. 😄 I honestly don't think that ILmerge had anything to do with this process (I was merely trying to be thorough in my description of the issue); it's far more likely that partial-trust was the trigger for the issue I had. After all, the DLLs did work for me in CRM after ILmerging in a non-sandbox (full-trust) setting... but while great for debugging, it's not a good method to deploy online CRM solutions. 😉

[twsouthwick]

Perfect! Yeah, this issue is a known one for partial trust apparently. If we had the ACPTA attribute in the assembly it would have compiled fine, but thankfully there is a compat switch for peverify. We'll get that released to NuGet soon. Thanks for verifying!