Skip to main content

Fatal Execution Engine Error when calling a WCF service in IIS

If you like nasty errors, this is one! It means more or less that the .NET framework itself has crashed. I have not seen this kind of errors a lot(luckily). Everytime we called a specific service, we succeeded in crashing the .NET framework.  After some investigation, we started to suspect the usage of IEnumerable<T> in one of our services. And finding this MS Connect call confirmed this suspicion.

The fault could be found in the DataContractSerializer class. Microsoft indicated that the DataContractSerializer issue is fixed in .NET 4.0, but there is not a hotfix available for .NET 3.5sp1 at this time.
The workaround they proposed  was to place all assemblies that contain types "T" used in contracts that have IEnumerable<T> into the GAC.  (In other words, if your contract has IEnumerable<T> elements, then all types T have to be strong-named & in the GAC.)


Why does this work?  The bug with DataContractSerializer apparently does not manifest itself when assemblies are loaded as "domain neutral" (shared across all appdomains.)  You can force strong-named/GAC'd assemblies to be loaded as "domain neutral" by using the LoaderOptimization attribute.  But if you're hosting in IIS, you are automatically getting LoaderOptimization(LoaderOptimization.MultiDomainHost) behavior for your application.  If you're not hosting in IIS, this bug doesn't seem to appear at all.

Labels:

Popular posts from this blog

DevToys–A swiss army knife for developers

As a developer there are a lot of small tasks you need to do as part of your coding, debugging and testing activities.  DevToys is an offline windows app that tries to help you with these tasks. Instead of using different websites you get a fully offline experience offering help for a large list of tasks. Many tools are available. Here is the current list: Converters JSON <> YAML Timestamp Number Base Cron Parser Encoders / Decoders HTML URL Base64 Text & Image GZip JWT Decoder Formatters JSON SQL XML Generators Hash (MD5, SHA1, SHA256, SHA512) UUID 1 and 4 Lorem Ipsum Checksum Text Escape / Unescape Inspector & Case Converter Regex Tester Text Comparer XML Validator Markdown Preview Graphic Color B
Read more

Help! I accidently enabled HSTS–on localhost

I ran into an issue after accidently enabling HSTS for a website on localhost. This was not an issue for the original website that was running in IIS and had a certificate configured. But when I tried to run an Angular app a little bit later on http://localhost:4200 the browser redirected me immediately to https://localhost . Whoops! That was not what I wanted in this case. To fix it, you need to go the network settings of your browser, there are available at: chrome://net-internals/#hsts edge://net-internals/#hsts brave://net-internals/#hsts Enter ‘localhost’ in the domain textbox under the Delete domain security policies section and hit Delete . That should do the trick…
Read more

Azure DevOps/ GitHub emoji

I’m really bad at remembering emoji’s. So here is cheat sheet with all emoji’s that can be used in tools that support the github emoji markdown markup: All credits go to rcaviers who created this list.
Read more