Get-MofSchemaObject: Missing error handling when calling method ImportClasses

[johlju]

Details of the scenario you tried and the problem that is occurring

When a resource have an schema.mof that is not correct and the method ImportClasses returns exceptions in the variable $exceptionCollection they are not handled.

DscResource.DocGenerator/source/Private/Get-MofSchemaObject.ps1

Line 79 in e161d60

$tempFilePath, $moduleInfo, $exceptionCollection

Steps to reproduce the problem

Have a resource with the schema.mof where there are two spaces after the colon and before the super class OMI_BaseResource, e.g. : OMI_BaseResource.

[ClassVersion("1.0.0"), FriendlyName("xDnsServerForwarder")]
class MSFT_xDnsServerForwarder :  OMI_BaseResource
{
    [Key, Description("Specifies the resource is a single instance, the value must be 'Yes'"), ValueMap{"Yes"}, Values{"Yes"}] String IsSingleInstance;
    [Write] String IPAddresses[];
    [Write, Description("Validate if you want to use root hint on DNS Server.")] Boolean UseRootHint;
};

Expected behavior

Should throw the exception that is returned.

Current behavior

Just returns with $null and does not throw an exception.

Suggested solution to the issue

Make sure to throw the (first) exception.

    if ($exceptionCollection)
    {
        # Throw the first exception that was returned from ImportClasses().
        throw $exceptionCollection[0]
    }

This will return for example the following error so it would need a localized error message saying what schema file generated the error.

ERROR: Cim deserializer threw an error when deserializing file C:\Users\JOHAN~1.LJU\AppData\Local\Temp\DscMofHelper_30c3f093-e2f0-4794-841e-47c551db2105.tmp.

Running Get-Error will then return the full error in the InnerExeception (at least in this case).

    InnerException :
        Type            : Microsoft.Management.Infrastructure.CimException
        NativeErrorCode : Failed
        ErrorData       : OMI_Error
        StatusCode      : 1
        TargetSite      :
            Name          : ThrowIfMiResultFailure
            DeclaringType : Microsoft.Management.Infrastructure.CimException
            MemberType    : Method
            Module        : Microsoft.Management.Infrastructure.dll
        StackTrace      :
   at Microsoft.Management.Infrastructure.CimException.ThrowIfMiResultFailure(MiResult result, String errorMessage, InstanceHandle errorData)
   at Microsoft.Management.Infrastructure.CimException.ThrowIfMiResultFailure(MiResult result, InstanceHandle errorData)
   at Microsoft.Management.Infrastructure.Serialization.CimMofDeserializer.DeserializeClassHandle(Byte[] serializedData, UInt32& offset, IEnumerable`1 cimClasses, String computerName, String
namespaceName, OnClassNeeded onClassNeededCallback, GetIncludedFileContent getIncludedFileCallback)
   at Microsoft.Management.Infrastructure.Serialization.CimMofDeserializer.DeserializeClasses(Byte[] serializedData, UInt32& offset, IEnumerable`1 classes, String computerName, String namespaceName,  OnClassNeeded onClassNeededCallback, GetIncludedFileContent getIncludedFileCallback)
   at Microsoft.PowerShell.DesiredStateConfiguration.CimDSCParser.ParseSchemaMof(String filePath)
        Message         : Class 'MSFT_xDnsServerForwarder' has undefined super class 'OMI_BaseResource'
                          At line:7, char:2
                          Buffer:
                          Boolean UseRootHint;
                          };^



        Source          : Microsoft.Management.Infrastructure
        HResult         : -2146233088

The operating system the target node is running

Windows 10

Version and build of PowerShell the target node is running

Name                           Value
----                           -----
PSVersion                      7.0.0
PSEdition                      Core
GitCommitId                    7.0.0
OS                             Microsoft Windows 10.0.19041
Platform                       Win32NT
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0

Version of the module that was used

0.4.0