Cosmos Full Text Search support

- Adding model building API to configure property as full-text search enabled, as well as setup the index for it,
- Adding model validation (e.g. FTS index not matching FTS property),
- Adding EF.Functions stubs and translations for FullTextContains, FullTextContainsAll, FullTextContainsAny, FullTextScore and RRF (for hybrid),
- Adding logic in SelectExpression to produce ORDER BY RANK when necessary,
- Adding validation when attempting to mix with ORDER BY RANK with regular ORDER BY,
- Rewrite OFFSET/LIMIT from parameter to constant when ORDER BY RANK is present.
- Adding model building support for default language on the container level

Also fixed / added support for vector search on owned types (since it shares logic with FTS) and added some tests.

outstanding work:
- support for FTS Container building using Azure.ResourceManager.CosmosDb (currently blocked on updated package being released)

Fixes #35476
Fixes #35853
Fixes #35867
Fixes #35852

Author: maumar

Diff for: Directory.Packages.props

@@ -37,7 +37,7 @@
     <PackageVersion Include="Microsoft.DotNet.Build.Tasks.Templating" Version="$(MicrosoftDotNetBuildTasksTemplatingVersion)" />
 
     <!-- Azure SDK for .NET dependencies -->
-    <PackageVersion Include="Microsoft.Azure.Cosmos" Version="3.46.0" />
+    <PackageVersion Include="Microsoft.Azure.Cosmos" Version="3.49.0-preview.0" />
 
     <!-- SQL Server dependencies -->
     <PackageVersion Include="Microsoft.Data.SqlClient" Version="6.0.1" />

Diff for: src/EFCore.Cosmos/EFCore.Cosmos.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <Description>Azure Cosmos provider for Entity Framework Core.</Description>
@@ -12,6 +12,7 @@
     <NoWarn>$(NoWarn);EF9101</NoWarn> <!-- Metrics is experimental -->
     <NoWarn>$(NoWarn);EF9102</NoWarn> <!-- Paging is experimental -->
     <NoWarn>$(NoWarn);EF9103</NoWarn> <!-- Vector search is experimental -->
+    <NoWarn>$(NoWarn);EF9104</NoWarn> <!-- Full-text search is experimental -->
   </PropertyGroup>
 
   <ItemGroup>

Diff for: src/EFCore.Cosmos/Extensions/CosmosDbFunctionsExtensions.cs

@@ -52,6 +52,60 @@ public static T CoalesceUndefined<T>(
         T expression2)
         => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(CoalesceUndefined)));
 
+    /// <summary>
+    ///     Checks if the specified property contains the given keyword using full-text search.
+    /// </summary>
+    /// <param name="_">The <see cref="DbFunctions" /> instance.</param>
+    /// <param name="property">The property to search.</param>
+    /// <param name="keyword">The keyword to search for.</param>
+    /// <returns><see langword="true" /> if the property contains the keyword; otherwise, <see langword="false" />.</returns>
+    [Experimental(EFDiagnostics.CosmosFullTextSearchExperimental)]
+    public static bool FullTextContains(this DbFunctions _, string property, string keyword)
+        => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(FullTextContains)));
+
+    /// <summary>
+    ///     Checks if the specified property contains all the given keywords using full-text search.
+    /// </summary>
+    /// <param name="_">The <see cref="DbFunctions" /> instance.</param>
+    /// <param name="property">The property to search.</param>
+    /// <param name="keywords">The keywords to search for.</param>
+    /// <returns><see langword="true" /> if the property contains all the keywords; otherwise, <see langword="false" />.</returns>
+    [Experimental(EFDiagnostics.CosmosFullTextSearchExperimental)]
+    public static bool FullTextContainsAll(this DbFunctions _, string property, params string[] keywords)
+        => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(FullTextContainsAll)));
+
+    /// <summary>
+    ///     Checks if the specified property contains any of the given keywords using full-text search.
+    /// </summary>
+    /// <param name="_">The <see cref="DbFunctions" /> instance.</param>
+    /// <param name="property">The property to search.</param>
+    /// <param name="keywords">The keywords to search for.</param>
+    /// <returns><see langword="true" /> if the property contains any of the keywords; otherwise, <see langword="false" />.</returns>
+    [Experimental(EFDiagnostics.CosmosFullTextSearchExperimental)]
+    public static bool FullTextContainsAny(this DbFunctions _, string property, params string[] keywords)
+        => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(FullTextContainsAny)));
+
+    /// <summary>
+    ///     Returns the full-text search score for the specified property and keywords.
+    /// </summary>
+    /// <param name="_">The <see cref="DbFunctions" /> instance.</param>
+    /// <param name="property">The property to score.</param>
+    /// <param name="keywords">The keywords to score by.</param>
+    /// <returns>The full-text search score.</returns>
+    [Experimental(EFDiagnostics.CosmosFullTextSearchExperimental)]
+    public static double FullTextScore(this DbFunctions _, string property, params string[] keywords)
+        => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(FullTextScore)));
+
+    /// <summary>
+    ///     Combines scores provided by two or more specified functions.
+    /// </summary>
+    /// <param name="_">The <see cref="DbFunctions" /> instance.</param>
+    /// <param name="functions">The functions to compute the score for.</param>
+    /// <returns>The combined score.</returns>
+    [Experimental(EFDiagnostics.CosmosFullTextSearchExperimental)]
+    public static double Rrf(this DbFunctions _, params double[] functions)
+        => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(Rrf)));
+
     /// <summary>
     ///     Returns the distance between two vectors, using the distance function and data type defined using
     ///     <see

Diff for: src/EFCore.Cosmos/Extensions/CosmosEntityTypeBuilderExtensions.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Diagnostics.CodeAnalysis;
 using Microsoft.EntityFrameworkCore.Cosmos.Metadata.Internal;
 
 // ReSharper disable once CheckNamespace
@@ -883,6 +884,92 @@ public static bool CanSetDefaultTimeToLive(
         bool fromDataAnnotation = false)
         => entityTypeBuilder.CanSetAnnotation(CosmosAnnotationNames.DefaultTimeToLive, seconds, fromDataAnnotation);
 
+    /// <summary>
+    ///     Configures a default language to use for full-text search at container scope.
+    /// </summary>
+    /// <remarks>
+    ///     See <see href="https://aka.ms/efcore-docs-modeling">Modeling entity types and relationships</see>, and
+    ///     <see href="https://aka.ms/efcore-docs-cosmos">Accessing Azure Cosmos DB with EF Core</see> for more information and examples.
+    /// </remarks>
+    /// <param name="entityTypeBuilder">The builder for the entity type being configured.</param>
+    /// <param name="language">The default language.</param>
+    /// <returns>The same builder instance so that multiple calls can be chained.</returns>
+    [Experimental(EFDiagnostics.CosmosFullTextSearchExperimental)]
+    public static EntityTypeBuilder HasDefaultFullTextLanguage(
+        this EntityTypeBuilder entityTypeBuilder,
+        string? language)
+    {
+        entityTypeBuilder.Metadata.SetDefaultFullTextSearchLanguage(language);
+
+        return entityTypeBuilder;
+    }
+
+    /// <summary>
+    ///     Configures a default language to use for full-text search at container scope.
+    /// </summary>
+    /// <remarks>
+    ///     See <see href="https://aka.ms/efcore-docs-modeling">Modeling entity types and relationships</see>, and
+    ///     <see href="https://aka.ms/efcore-docs-cosmos">Accessing Azure Cosmos DB with EF Core</see> for more information and examples.
+    /// </remarks>
+    /// <param name="entityTypeBuilder">The builder for the entity type being configured.</param>
+    /// <param name="language">The default language.</param>
+    /// <returns>The same builder instance so that multiple calls can be chained.</returns>
+    [Experimental(EFDiagnostics.CosmosFullTextSearchExperimental)]
+    public static EntityTypeBuilder<TEntity> HasDefaultFullTextLanguage<TEntity>(
+        this EntityTypeBuilder<TEntity> entityTypeBuilder,
+        string? language)
+        where TEntity : class
+        => (EntityTypeBuilder<TEntity>)HasDefaultFullTextLanguage((EntityTypeBuilder)entityTypeBuilder, language);
+
+    /// <summary>
+    ///     Configures a default language to use for full-text search at container scope.
+    /// </summary>
+    /// <remarks>
+    ///     See <see href="https://aka.ms/efcore-docs-modeling">Modeling entity types and relationships</see>, and
+    ///     <see href="https://aka.ms/efcore-docs-cosmos">Accessing Azure Cosmos DB with EF Core</see> for more information and examples.
+    /// </remarks>
+    /// <param name="entityTypeBuilder">The builder for the entity type being configured.</param>
+    /// <param name="language">The default language.</param>
+    /// <param name="fromDataAnnotation">Indicates whether the configuration was specified using a data annotation.</param>
+    /// <returns>
+    ///     The same builder instance if the configuration was applied,
+    ///     <see langword="null" /> otherwise.
+    /// </returns>
+    [Experimental(EFDiagnostics.CosmosFullTextSearchExperimental)]
+    public static IConventionEntityTypeBuilder? HasDefaultFullTextLanguage(
+        this IConventionEntityTypeBuilder entityTypeBuilder,
+        string? language,
+        bool fromDataAnnotation = false)
+    {
+        if (!entityTypeBuilder.CanSetDefaultFullTextLanguage(language, fromDataAnnotation))
+        {
+            return null;
+        }
+
+        entityTypeBuilder.Metadata.SetDefaultFullTextSearchLanguage(language, fromDataAnnotation);
+
+        return entityTypeBuilder;
+    }
+
+    /// <summary>
+    ///     Returns a value indicating whether the default full-text language can be set
+    ///     from the current configuration source
+    /// </summary>
+    /// <remarks>
+    ///     See <see href="https://aka.ms/efcore-docs-modeling">Modeling entity types and relationships</see>, and
+    ///     <see href="https://aka.ms/efcore-docs-cosmos">Accessing Azure Cosmos DB with EF Core</see> for more information and examples.
+    /// </remarks>
+    /// <param name="entityTypeBuilder">The builder for the entity type being configured.</param>
+    /// <param name="language">The default language.</param>
+    /// <param name="fromDataAnnotation">Indicates whether the configuration was specified using a data annotation.</param>
+    /// <returns><see langword="true" /> if the configuration can be applied.</returns>
+    [Experimental(EFDiagnostics.CosmosFullTextSearchExperimental)]
+    public static bool CanSetDefaultFullTextLanguage(
+        this IConventionEntityTypeBuilder entityTypeBuilder,
+        string? language,
+        bool fromDataAnnotation = false)
+        => entityTypeBuilder.CanSetAnnotation(CosmosAnnotationNames.DefaultFullTextSearchLanguage, language, fromDataAnnotation);
+
     /// <summary>
     ///     Configures the manual provisioned throughput offering.
     /// </summary>

Diff for: src/EFCore.Cosmos/Extensions/CosmosEntityTypeExtensions.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Diagnostics.CodeAnalysis;
 using Microsoft.EntityFrameworkCore.Cosmos.Metadata.Internal;
 
 // ReSharper disable once CheckNamespace
@@ -586,4 +587,52 @@ public static void SetThroughput(this IMutableEntityType entityType, int? throug
     public static ConfigurationSource? GetThroughputConfigurationSource(this IConventionEntityType entityType)
         => entityType.FindAnnotation(CosmosAnnotationNames.Throughput)
             ?.GetConfigurationSource();
+
+    /// <summary>
+    ///     Returns the default language for the full-text search at container scope.
+    /// </summary>
+    /// <param name="entityType">The entity type.</param>
+    /// <returns>The default language for the full-text search.</returns>
+    [Experimental(EFDiagnostics.CosmosFullTextSearchExperimental)]
+    public static string? GetDefaultFullTextSearchLanguage(this IReadOnlyEntityType entityType)
+        => entityType.BaseType != null
+            ? entityType.GetRootType().GetDefaultFullTextSearchLanguage()
+            : (string?)entityType[CosmosAnnotationNames.DefaultFullTextSearchLanguage];
+
+    /// <summary>
+    ///     Sets the default language for the full-text search at container scope.
+    /// </summary>
+    /// <param name="entityType">The entity type.</param>
+    /// <param name="language">The default language for the full-text search.</param>
+    [Experimental(EFDiagnostics.CosmosFullTextSearchExperimental)]
+    public static void SetDefaultFullTextSearchLanguage(this IMutableEntityType entityType, string? language)
+        => entityType.SetOrRemoveAnnotation(
+            CosmosAnnotationNames.DefaultFullTextSearchLanguage,
+            language);
+
+    /// <summary>
+    ///     Sets the default language for the full-text search at container scope.
+    /// </summary>
+    /// <param name="entityType">The entity type.</param>
+    /// <param name="language">The default language for the full-text search.</param>
+    /// <param name="fromDataAnnotation">Indicates whether the configuration was specified using a data annotation.</param>
+    [Experimental(EFDiagnostics.CosmosFullTextSearchExperimental)]
+    public static string? SetDefaultFullTextSearchLanguage(
+        this IConventionEntityType entityType,
+        string? language,
+        bool fromDataAnnotation = false)
+        => (string?)entityType.SetOrRemoveAnnotation(
+            CosmosAnnotationNames.DefaultFullTextSearchLanguage,
+            language,
+            fromDataAnnotation)?.Value;
+
+    /// <summary>
+    ///     Gets the <see cref="ConfigurationSource" /> for the default full-text search language at container scope.
+    /// </summary>
+    /// <param name="entityType">The entity type to find configuration source for.</param>
+    /// <returns>The <see cref="ConfigurationSource" /> for the default full-text search language.</returns>
+    [Experimental(EFDiagnostics.CosmosFullTextSearchExperimental)]
+    public static ConfigurationSource? GetDefaultFullTextSearchLanguageConfigurationSource(this IConventionEntityType entityType)
+        => entityType.FindAnnotation(CosmosAnnotationNames.DefaultFullTextSearchLanguage)
+            ?.GetConfigurationSource();
 }