Unhandled exceptions

[redcrayonn]

We've started to use your extension in combination with our webapplications. So far we've managed to fix a lot of SCSS errors which we otherwise wouldn't have noticed.

But one thing seems odd to us; there's a lot of unhandled exceptions which prevent you from starting a debugging session with for example MVC .NET 4.7.1.

My questions is whether it is at all possible to catch these exceptions and pass / bubble them to the application. We already handle exceptions thrown by the sass compiler, but it seems some exceptions take place within your extension which we cannot handle. Is it at all possible to handle them one way or another?

Error:
An unhandled exception of type 'System.AccessViolationException' occurred in Unknown Module.
Attempted to read or write protected memory. This is often an indication that other memory is corrupt.

Reproduction:

• MVC .NET web application with sass.
• Remove a trailing { on a random class.
• Try to debug the application.

We'd love to hear your feedback!

[Taritsyn]

Hello, Olaf!

Thanks for information! In the near future I will research this problem.

[Taritsyn]

Hello, Olaf!

I cannot reproduce this error.

You are using a modified or original version of the LibSass? Show me the full error message with stack trace.

[DaveEmmerson]

at LibSassHost.Helpers.MarshallingHelpers.PtrToString(IntPtr ptr)
at LibSassHost.Internal.SassCompilerProxy.FillManagedContextError(SassContextBase context, Sass_Context& ctx)
at LibSassHost.Internal.SassCompilerProxy.Compile(SassDataContext dataContext)
at LibSassHost.SassCompiler.InnerCompile(String content, Boolean indentedSyntax, String inputPath, String outputPath, String sourceMapPath, CompilationOptions options)
at LibSassHost.SassCompiler.Compile(String content, String inputPath, String outputPath, String sourceMapPath, CompilationOptions options)
at BundleTransformer.SassAndScss.Translators.SassAndScssTranslator.InnerTranslate(IAsset asset, CompilationOptions sassOptions, Boolean enableNativeMinification)
at BundleTransformer.SassAndScss.Translators.SassAndScssTranslator.Translate(IList1 assets) at BundleTransformer.Core.Transformers.TransformerBase.Translate(IList1 assets, Boolean isDebugMode)
at BundleTransformer.Core.Transformers.TransformerBase.Transform(IList1 assets, BundleContext bundleContext, BundleResponse bundleResponse, VirtualPathProvider virtualPathProvider, Boolean isDebugMode) at BundleTransformer.Core.Transformers.TransformerBase.Process(BundleContext bundleContext, BundleResponse bundleResponse, Boolean isDebugMode) at BundleTransformer.Core.Transformers.TransformerBase.Process(BundleContext bundleContext, BundleResponse bundleResponse) at System.Web.Optimization.Bundle.ApplyTransforms(BundleContext context, String bundleContent, IEnumerable1 bundleFiles)
at System.Web.Optimization.Bundle.GenerateBundleResponse(BundleContext context)
at System.Web.Optimization.Bundle.GetBundleResponse(BundleContext context)
at System.Web.Optimization.BundleResolver.GetBundleContents(String virtualPath)
at System.Web.Optimization.AssetManager.DeterminePathsToRender(IEnumerable`1 assets)
at System.Web.Optimization.AssetManager.RenderExplicit(String tagFormat, String[] paths)
at System.Web.Optimization.Styles.RenderFormat(String tagFormat, String[] paths)
at System.Web.Optimization.Styles.Render(String[] paths)

LibSassHost.1.2.7
LibSassHost.Native.win-x86.1.2.7

I'm trying to track down exactly where it fails.

[Taritsyn]

Hello, Dave!

You have only given a stack trace. I don't see the error message itself.

[DaveEmmerson]

Hi Same as the original poster: Error: An unhandled exception of type 'System.AccessViolationException' occurred in Unknown Module. Attempted to read or write protected memory. This is often an indication that other memory is corrupt. Thought I'd just hijack the thread seeing as it was the same issue and there was no repro possible :)

[Taritsyn]

@DaveEmmerson Is this error persistent?

Apparently it occurs during processing of the Sass syntax error:

…
at LibSassHost.Internal.SassCompilerProxy.FillManagedContextError(SassContextBase context, Sass_Context& ctx)
…

[DaveEmmerson]

Yeah, if I exclude the files with syntax errors it is fine. With a syntax error it fails like that quite often, but sometimes I can get the actual syntax error exception first before it fails completely. I'm trying to get a local build of the library running so I can debug, but ran out of time for today.

…

[Taritsyn]

What version of .NET are you using? Implementation of the PtrToString method just depends on it.

[DaveEmmerson]

What version of .NET are you using? Implementation of the PtrToString <https://github.com/Taritsyn/LibSassHost/blob/df7df2fa6b83d48a643a38b44088cf22fee5bbf0/src/LibSassHost/Helpers/MarshallingHelpers.cs#L102-L139> method just depends on

I'm not at work now, but I believe the project is a. Net framework 4.6.2 one I'll be able to double check on monday Thanks

…

[DaveEmmerson]

Hi

Yeah, it's framework and 4.6.2 on this project.

Thanks

[Taritsyn]

@redcrayonn @DaveEmmerson In version 1.2.8 fixed this error. The error was at the LibSass level.

[DaveEmmerson]

@Taritsyn thanks! I've created some local nuget packages of the latest commit and updated my libsasshost/libsassnative/bundletransformer.sass references and it seems to be working (in my sample size of 1 error 😁 )

[Taritsyn]

@DaveEmmerson Why create local nuget packages? Packages are in release.

[DaveEmmerson]

Ah, woops.

Does https://github.com/Taritsyn/BundleTransformer/blob/64c05f32757e469edb3b2e3f7d7d63dd6c0f82d8/src/BundleTransformer.SassAndScss/BundleTransformer.SassAndScss.csproj#L31 need to be updated though?

I'm very new to LibSass (like 2 days in), so I'm not 100% on how all the bits fit together yet.

[Taritsyn]

There were no changes in interface of the LibSassHost library, so you can just update the LibSassHost's packages.

[DaveEmmerson]

👍 thanks again - works fine after a good number of parse errors.