MissingMethodException: Method not found exception

[jrowe88]

Hello - I updated to the latest version of configuration builder and am getting the following exception:

System.MissingMethodException: Method not found: 'System.Threading.Tasks.ValueTask`1<Boolean> System.Collections.Generic.IAsyncEnumerator`1.MoveNextAsync()'. 

I'm not sure how to resolve this. I am using the latest (version 8.0.0) Microsoft.Bcl.AsyncInterfaces which should include the supposedly missing method. All the configuration builder libraries are the latest version.

Stack Trace

[MissingMethodException: Method not found: 'System.Threading.Tasks.ValueTask`1<Boolean> System.Collections.Generic.IAsyncEnumerator`1.MoveNextAsync()'.]
   Microsoft.Configuration.ConfigurationBuilders.<GetAllValuesAsync>d__39.MoveNext() +0
   System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1.Start(TStateMachine& stateMachine) +122
   Microsoft.Configuration.ConfigurationBuilders.AzureAppConfigurationBuilder.GetAllValuesAsync(String prefix) +97
   Microsoft.Configuration.ConfigurationBuilders.<<GetAllValues>b__0>d.MoveNext() +55

[AggregateException: One or more errors occurred.]
   System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotification) +4923493
   Microsoft.Configuration.ConfigurationBuilders.AzureAppConfigurationBuilder.GetAllValues(String prefix) +130
   Microsoft.Configuration.ConfigurationBuilders.KeyValueConfigBuilder.EnsureGreedyInitialized() +222

[KeyValueConfigBuilderException: 'DefaultConfig' GetAllValues() Error: One or more errors occurred.]
   Microsoft.Configuration.ConfigurationBuilders.KeyValueConfigBuilder.EnsureGreedyInitialized() +657
   Microsoft.Configuration.ConfigurationBuilders.KeyValueConfigBuilder.ProcessConfigurationSection(ConfigurationSection configSection) +740
   System.Configuration.ConfigurationBuilderChain.ProcessConfigurationSection(ConfigurationSection configSection) +136

Configuration Section showing defined builders

     ...
     <section name="configBuilders" type="System.Configuration.ConfigurationBuildersSection, System.Configuration, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" restartOnExternalChanges="false" requirePermission="false" />
  </configSections>

  <configBuilders>
    <builders>
      <add name="EnvironmentVariableConfig" mode="Token" escapeExpandedValues="true" type="Microsoft.Configuration.ConfigurationBuilders.EnvironmentConfigBuilder, Microsoft.Configuration.ConfigurationBuilders.Environment" />

      <add name="DefaultConfig" mode="Greedy" prefix="" stripPrefix="false" enabled="true" labelFilter="" useAzureKeyVault="true" connectionString="${Azure.AppConfiguration.Connection}" type="Microsoft.Configuration.ConfigurationBuilders.AzureAppConfigurationBuilder, Microsoft.Configuration.ConfigurationBuilders.AzureAppConfiguration" />

      <add name="DeployEnvironmentConfig" mode="Greedy" prefix="" stripPrefix="false" enabled="true" labelFilter="${Deploy.Environment}" useAzureKeyVault="true" connectionString="${Azure.AppConfiguration.Connection}" type="Microsoft.Configuration.ConfigurationBuilders.AzureAppConfigurationBuilder, Microsoft.Configuration.ConfigurationBuilders.AzureAppConfiguration" />

      <add name="DeployEnvironmentExpansions" mode="Token" escapeExpandedValues="true" tokenPattern="\${([a-zA-Z0-9_.:]+)\}" enabled="true" prefix="" stripPrefix="false" labelFilter="${Deploy.Environment}" useAzureKeyVault="true" connectionString="${Azure.AppConfiguration.Connection}" type="Microsoft.Configuration.ConfigurationBuilders.AzureAppConfigurationBuilder, Microsoft.Configuration.ConfigurationBuilders.AzureAppConfiguration" />

    </builders>
  </configBuilders>

[StephenMolloy]

At first glance, I don't see anything that suggests this is a problem with the config builders themselves. There might be a mismatch of packages or some other project confusion here. But it's hard to say what the root issue is from the information given here.

I would try to make sure that all your nuget package references are in sync. Sometimes different packages ask for different versions of the same dependency. Clear your cache, clean your solution. Restore and rebuild. You could also try fiddling with binding redirects to see if that's able to resolve your issue. If you still encounter the error and you're able to share a small sample repro project, then folks here might be able to see where the disconnect is.

I see this issue was filed quite some time ago. Hopefully you've been able to resolve this since?