Support hierarchical partition keys in Cosmos provider

Fixes #28186
Fixes #28265
Fixes #33535

Also:
- Allow non-string partition key values
- Warn if no partition key has been defined
- Use a value converter if needed for values passed to WithPartitionKey (This is probably a bug, but should be docced as a breaking change anyway.)

Updated based on review feedback

src/EFCore.Cosmos/Diagnostics/CosmosEventId.cs

@@ -34,7 +34,11 @@ private enum Id
         ExecutedReadItem,
         ExecutedCreateItem,
         ExecutedReplaceItem,
-        ExecutedDeleteItem
+        ExecutedDeleteItem,
+
+        // Model validation events
+        NoPartitionKeyDefined = CoreEventId.ProviderBaseId + 600,
+
     }
 
     private static readonly string DatabasePrefix = DbLoggerCategory.Database.Name + ".";
@@ -149,4 +153,21 @@ public static readonly EventId ExecutedReplaceItem
     /// </remarks>
     public static readonly EventId ExecutedDeleteItem
         = new((int)Id.ExecutedDeleteItem, CommandPrefix + Id.ExecutedDeleteItem);
+
+    private static EventId MakeValidationId(Id id)
+        => new((int)id, DbLoggerCategory.Model.Validation.Name + "." + id);
+
+    /// <summary>
+    ///     No partition key has been configured for an entity type. It is highly recommended that an appropriate partition key be defined.
+    ///     See https://aka.ms/efdocs-cosmos-partition-keys for more information.
+    /// </summary>
+    /// <remarks>
+    ///     <para>
+    ///         This event is in the <see cref="DbLoggerCategory.Model.Validation" /> category.
+    ///     </para>
+    ///     <para>
+    ///         This event uses the <see cref="EntityTypeEventData" /> payload when used with a <see cref="DiagnosticSource" />.
+    ///     </para>
+    /// </remarks>
+    public static readonly EventId NoPartitionKeyDefined = MakeValidationId(Id.NoPartitionKeyDefined);
 }

src/EFCore.Cosmos/Diagnostics/CosmosItemCommandExecutedEventData.cs

@@ -21,7 +21,7 @@ public class CosmosItemCommandExecutedEventData : EventData
     /// <param name="activityId">The activity ID.</param>
     /// <param name="resourceId">The ID of the resource being read.</param>
     /// <param name="containerId">The ID of the Cosmos container being queried.</param>
-    /// <param name="partitionKey">The key of the Cosmos partition that the query is using.</param>
+    /// <param name="partitionKeyValue">The key of the Cosmos partition that the query is using.</param>
     /// <param name="logSensitiveData">Indicates whether the application allows logging of sensitive data.</param>
     public CosmosItemCommandExecutedEventData(
         EventDefinitionBase eventDefinition,
@@ -31,7 +31,7 @@ public CosmosItemCommandExecutedEventData(
         string activityId,
         string containerId,
         string resourceId,
-        string? partitionKey,
+        PartitionKey partitionKeyValue,
         bool logSensitiveData)
         : base(eventDefinition, messageGenerator)
     {
@@ -40,7 +40,7 @@ public CosmosItemCommandExecutedEventData(
         ActivityId = activityId;
         ContainerId = containerId;
         ResourceId = resourceId;
-        PartitionKey = partitionKey;
+        PartitionKeyValue = partitionKeyValue;
         LogSensitiveData = logSensitiveData;
     }
 
@@ -72,7 +72,7 @@ public CosmosItemCommandExecutedEventData(
     /// <summary>
     ///     The key of the Cosmos partition that the query is using.
     /// </summary>
-    public virtual string? PartitionKey { get; }
+    public virtual PartitionKey PartitionKeyValue { get; }
 
     /// <summary>
     ///     Indicates whether the application allows logging of sensitive data.

src/EFCore.Cosmos/Diagnostics/CosmosQueryEventData.cs

@@ -17,22 +17,22 @@ public class CosmosQueryEventData : EventData
     /// <param name="eventDefinition">The event definition.</param>
     /// <param name="messageGenerator">A delegate that generates a log message for this event.</param>
     /// <param name="containerId">The ID of the Cosmos container being queried.</param>
-    /// <param name="partitionKey">The key of the Cosmos partition that the query is using.</param>
+    /// <param name="partitionKeyValue">The key value of the Cosmos partition that the query is using.</param>
     /// <param name="parameters">Name/values for each parameter in the Cosmos Query.</param>
     /// <param name="querySql">The SQL representing the query.</param>
     /// <param name="logSensitiveData">Indicates whether the application allows logging of sensitive data.</param>
     public CosmosQueryEventData(
         EventDefinitionBase eventDefinition,
         Func<EventDefinitionBase, EventData, string> messageGenerator,
         string containerId,
-        string? partitionKey,
+        PartitionKey partitionKeyValue,
         IReadOnlyList<(string Name, object? Value)> parameters,
         string querySql,
         bool logSensitiveData)
         : base(eventDefinition, messageGenerator)
     {
         ContainerId = containerId;
-        PartitionKey = partitionKey;
+        PartitionKeyValue = partitionKeyValue;
         Parameters = parameters;
         QuerySql = querySql;
         LogSensitiveData = logSensitiveData;
@@ -46,7 +46,7 @@ public CosmosQueryEventData(
     /// <summary>
     ///     The key of the Cosmos partition that the query is using.
     /// </summary>
-    public virtual string? PartitionKey { get; }
+    public virtual PartitionKey PartitionKeyValue { get; }
 
     /// <summary>
     ///     Name/values for each parameter in the Cosmos Query.

src/EFCore.Cosmos/Diagnostics/CosmosQueryExecutedEventData.cs

@@ -20,7 +20,7 @@ public class CosmosQueryExecutedEventData : EventData
     /// <param name="requestCharge">The request charge in RU.</param>
     /// <param name="activityId">The activity ID.</param>
     /// <param name="containerId">The ID of the Cosmos container being queried.</param>
-    /// <param name="partitionKey">The key of the Cosmos partition that the query is using.</param>
+    /// <param name="partitionKeyValue">The key value of the Cosmos partition that the query is using.</param>
     /// <param name="parameters">Name/values for each parameter in the Cosmos Query.</param>
     /// <param name="querySql">The SQL representing the query.</param>
     /// <param name="logSensitiveData">Indicates whether the application allows logging of sensitive data.</param>
@@ -31,7 +31,7 @@ public CosmosQueryExecutedEventData(
         double requestCharge,
         string activityId,
         string containerId,
-        string? partitionKey,
+        PartitionKey partitionKeyValue,
         IReadOnlyList<(string Name, object? Value)> parameters,
         string querySql,
         bool logSensitiveData)
@@ -41,7 +41,7 @@ public CosmosQueryExecutedEventData(
         RequestCharge = requestCharge;
         ActivityId = activityId;
         ContainerId = containerId;
-        PartitionKey = partitionKey;
+        PartitionKeyValue = partitionKeyValue;
         Parameters = parameters;
         QuerySql = querySql;
         LogSensitiveData = logSensitiveData;
@@ -70,7 +70,7 @@ public CosmosQueryExecutedEventData(
     /// <summary>
     ///     The key of the Cosmos partition that the query is using.
     /// </summary>
-    public virtual string? PartitionKey { get; }
+    public virtual PartitionKey PartitionKeyValue { get; }
 
     /// <summary>
     ///     Name/values for each parameter in the Cosmos Query.

src/EFCore.Cosmos/Diagnostics/CosmosReadItemEventData.cs

@@ -18,20 +18,20 @@ public class CosmosReadItemEventData : EventData
     /// <param name="messageGenerator">A delegate that generates a log message for this event.</param>
     /// <param name="resourceId">The ID of the resource being read.</param>
     /// <param name="containerId">The ID of the Cosmos container being queried.</param>
-    /// <param name="partitionKey">The key of the Cosmos partition that the query is using.</param>
+    /// <param name="partitionKeyValue">The key value of the Cosmos partition that the query is using.</param>
     /// <param name="logSensitiveData">Indicates whether the application allows logging of sensitive data.</param>
     public CosmosReadItemEventData(
         EventDefinitionBase eventDefinition,
         Func<EventDefinitionBase, EventData, string> messageGenerator,
         string resourceId,
         string containerId,
-        string? partitionKey,
+        PartitionKey partitionKeyValue,
         bool logSensitiveData)
         : base(eventDefinition, messageGenerator)
     {
         ResourceId = resourceId;
         ContainerId = containerId;
-        PartitionKey = partitionKey;
+        PartitionKeyValue = partitionKeyValue;
         LogSensitiveData = logSensitiveData;
     }
 
@@ -48,7 +48,7 @@ public CosmosReadItemEventData(
     /// <summary>
     ///     The key of the Cosmos partition that the query is using.
     /// </summary>
-    public virtual string? PartitionKey { get; }
+    public virtual PartitionKey PartitionKeyValue { get; }
 
     /// <summary>
     ///     Indicates whether the application allows logging of sensitive data.