JSON.NET序列化对象时触发VerificationException问题排查求助

Hey there, let's work through this VerificationException issue you're hitting with JSON.NET. Since it only pops up on machine A but runs smoothly on B, the problem is almost certainly tied to environment-specific differences between the two machines. Here's a structured approach to dig deeper and fix it:

Further Troubleshooting Steps #

• Check Code Access Security (CAS) Policies: JSON.NET uses [assembly: AllowPartiallyTrustedCallers], so machine A might have stricter CAS settings blocking verification. Use the caspol.exe tool (part of .NET Framework) to compare policy levels between the two machines—pay attention to whether machine A enforces partial trust restrictions that B doesn't.
• Validate JSON.NET Versions & Deployment: Double-check that both machines use the exact same JSON.NET version. Machine A might have an older version in the GAC (Global Assembly Cache) overriding your project's local reference, or vice versa. You can inspect the GAC by navigating to C:\Windows\Microsoft.NET\assembly or running gacutil.exe /l Newtonsoft.Json.
• Compare .NET Framework Updates: Look at Windows Update histories for both machines, focusing on .NET Framework-related patches. A recent security update on machine A might have tightened CLR verification rules, triggering this exception where it didn't before.
• Dig Into Exception Details: Grab the full stack trace of the VerificationException—it should specify exactly which method or assembly failed verification. This will point you directly to the root cause (e.g., a specific serialization logic in JSON.NET that fails on machine A's stricter checks).
• Check Web App Trust Level: If this is a web application, verify the trust level in web.config. Machine A's IIS might run the app pool in partial trust mode (like Medium Trust) while machine B uses Full Trust. Look for the <trust> element in your config to confirm.

Potential Fixes #

• Align Trust Settings: If machine A uses partial trust, switch the web app's trust level to Full Trust (if your environment allows it) or adjust CAS policies to grant necessary permissions to JSON.NET and your application.
• Standardize JSON.NET Deployment: Use a local copy of JSON.NET in your project (via NuGet) instead of relying on the GAC. This ensures the same version runs on both machines, eliminating version mismatch issues. Update to the latest stable JSON.NET version too—older releases might have known verification bugs.
• Roll Back or Update .NET Framework: If a recent .NET update on machine A causes the issue, try uninstalling that patch temporarily to see if the exception goes away. Alternatively, upgrade to the latest .NET Framework version, as Microsoft often fixes verification logic bugs in newer releases.
• Temporarily Disable CLR Verification (For Testing): Set the environment variable COMPLUS_verify=0 on machine A, then run your application. If the exception stops, this confirms it's a verification-related issue. Note: This is a troubleshooting step only—don't leave this enabled in production.
• Simplify Serialization Objects: Test with a minimal, basic object first. If that works, gradually add properties/types until the exception triggers. This helps you identify if a specific type (like dynamic objects, anonymous types, or custom serialization logic) is causing the verification failure.

内容的提问来源于stack exchange，提问作者Bassam Gamal