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.

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)
- add model building support for default language (superfluous for now, since only one language is supported),
- add more model validation tests for invalid scenarios (index on multiple columns, FTS on non-string etc)
- clean up exception messages and put them in a resource file,

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

@@ -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 search.</param>
+    /// <param name="keywords">The keywords to search for.</param>
+    /// <returns>The full-text search score.</returns>
+    [Experimental(EFDiagnostics.CosmosFullTextSearchExperimental)]
+    public static double FullTextScore(this DbFunctions _, string property, 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/CosmosIndexBuilderExtensions.cs

@@ -96,4 +96,84 @@ public static bool CanSetVectorIndexType(
         VectorIndexType? indexType,
         bool fromDataAnnotation = false)
         => indexBuilder.CanSetAnnotation(CosmosAnnotationNames.VectorIndexType, indexType, fromDataAnnotation);
+
+    /// <summary>
+    ///     Configures the index as a full-text index.
+    ///     See <see href="https://learn.microsoft.com/en-us/azure/cosmos-db/gen-ai/full-text-search">Full-text search in Azure Cosmos DB for NoSQL</see> for more information.
+    /// </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="indexBuilder">The builder for the index being configured.</param>
+    /// <param name="value">The value indicating whether the index is configured for Full-text search.</param>
+    /// <returns>A builder to further configure the index.</returns>
+    public static IndexBuilder ForFullText(this IndexBuilder indexBuilder, bool? value = true)
+    {
+        indexBuilder.Metadata.SetFullTextIndex(value);
+
+        return indexBuilder;
+    }
+
+    /// <summary>
+    ///     Configures the index as a full-text index.
+    ///     See <see href="https://learn.microsoft.com/en-us/azure/cosmos-db/gen-ai/full-text-search">Full-text search in Azure Cosmos DB for NoSQL</see> for more information.
+    /// </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="indexBuilder">The builder for the index being configured.</param>
+    /// <param name="value">The value indicating whether the index is configured for Full-text search.</param>
+    /// <returns>A builder to further configure the index.</returns>
+    public static IndexBuilder<TEntity> ForFullText<TEntity>(
+        this IndexBuilder<TEntity> indexBuilder,
+        bool? value = true)
+        => (IndexBuilder<TEntity>)ForFullText((IndexBuilder)indexBuilder, value);
+
+    /// <summary>
+    ///     Configures the index as a full-text index.
+    ///     See <see href="https://learn.microsoft.com/en-us/azure/cosmos-db/gen-ai/full-text-search">Full-text search in Azure Cosmos DB for NoSQL</see> for more information.
+    /// </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="indexBuilder">The builder for the index being configured.</param>
+    /// <param name="value">The value indicating whether the index is configured for Full-text search.</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>
+    public static IConventionIndexBuilder? ForFullText(
+        this IConventionIndexBuilder indexBuilder,
+        bool? value,
+        bool fromDataAnnotation = false)
+    {
+        if (indexBuilder.CanSetFullTextIndex(fromDataAnnotation))
+        {
+            indexBuilder.Metadata.SetFullTextIndex(value, fromDataAnnotation);
+            return indexBuilder;
+        }
+
+        return null;
+    }
+
+    /// <summary>
+    ///     Returns a value indicating whether the index can be configured as a Full-text index.
+    /// </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="indexBuilder">The builder for the index being configured.</param>
+    /// <param name="value">The value indicating whether the index is configured for Full-text search.</param>
+    /// <param name="fromDataAnnotation">Indicates whether the configuration was specified using a data annotation.</param>
+    /// <returns><see langword="true" /> if the index can be configured as a Full-text index.</returns>
+    public static bool CanSetFullTextIndex(
+        this IConventionIndexBuilder indexBuilder,
+        bool? value,
+        bool fromDataAnnotation = false)
+        => indexBuilder.CanSetAnnotation(CosmosAnnotationNames.FullTextIndex, value, fromDataAnnotation);
 }

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

@@ -14,7 +14,6 @@ namespace Microsoft.EntityFrameworkCore;
 ///     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>
-[Experimental(EFDiagnostics.CosmosVectorSearchExperimental)]
 public static class CosmosIndexExtensions
 {
     /// <summary>
@@ -23,6 +22,7 @@ public static class CosmosIndexExtensions
     /// </summary>
     /// <param name="index">The index.</param>
     /// <returns>The index type to use, or <see langword="null" /> if none is set.</returns>
+    [Experimental(EFDiagnostics.CosmosVectorSearchExperimental)]
     public static VectorIndexType? GetVectorIndexType(this IReadOnlyIndex index)
         => (index is RuntimeIndex)
             ? throw new InvalidOperationException(CoreStrings.RuntimeModelMissingData)
@@ -34,6 +34,7 @@ public static class CosmosIndexExtensions
     /// </summary>
     /// <param name="index">The index.</param>
     /// <param name="indexType">The index type to use.</param>
+    [Experimental(EFDiagnostics.CosmosVectorSearchExperimental)]
     public static void SetVectorIndexType(this IMutableIndex index, VectorIndexType? indexType)
         => index.SetAnnotation(CosmosAnnotationNames.VectorIndexType, indexType);
 
@@ -45,6 +46,7 @@ public static void SetVectorIndexType(this IMutableIndex index, VectorIndexType?
     /// <param name="index">The index.</param>
     /// <param name="fromDataAnnotation">Indicates whether the configuration was specified using a data annotation.</param>
     /// <returns>The configured value.</returns>
+    [Experimental(EFDiagnostics.CosmosVectorSearchExperimental)]
     public static string? SetVectorIndexType(
         this IConventionIndex index,
         VectorIndexType? indexType,
@@ -59,6 +61,57 @@ public static void SetVectorIndexType(this IMutableIndex index, VectorIndexType?
     /// </summary>
     /// <param name="property">The property.</param>
     /// <returns>The <see cref="ConfigurationSource" /> for whether the index is clustered.</returns>
+    [Experimental(EFDiagnostics.CosmosVectorSearchExperimental)]
     public static ConfigurationSource? GetVectorIndexTypeConfigurationSource(this IConventionIndex property)
         => property.FindAnnotation(CosmosAnnotationNames.VectorIndexType)?.GetConfigurationSource();
+
+    /// <summary>
+    ///     Returns the value indicating whether the index is configured for Full-text search.
+    ///     See <see href="https://learn.microsoft.com/en-us/azure/cosmos-db/gen-ai/full-text-search">Full-text search in Azure Cosmos DB for NoSQL</see> for more information.
+    /// </summary>
+    /// <param name="index">The index.</param>
+    /// <returns>The index type to use, or <see langword="null" /> if none is set.</returns>
+    [Experimental(EFDiagnostics.CosmosFullTextSearchExperimental)]
+    public static bool? IsFullTextIndex(this IReadOnlyIndex index)
+        => (index is RuntimeIndex)
+            ? throw new InvalidOperationException(CoreStrings.RuntimeModelMissingData)
+            : (bool?)index[CosmosAnnotationNames.FullTextIndex];
+
+    /// <summary>
+    ///     Configures the index for Full-text search.
+    ///     See <see href="https://learn.microsoft.com/en-us/azure/cosmos-db/gen-ai/full-text-search">Full-text search in Azure Cosmos DB for NoSQL</see> for more information.
+    /// </summary>
+    /// <param name="index">The index.</param>
+    /// <param name="value">The value indicating whether the index is configured for Full-text search.</param>
+    [Experimental(EFDiagnostics.CosmosFullTextSearchExperimental)]
+    public static void SetFullTextIndex(this IMutableIndex index, bool? value)
+        => index.SetAnnotation(CosmosAnnotationNames.FullTextIndex, value);
+
+    /// <summary>
+    ///     Configures the index for Full-text search.
+    ///     See <see href="https://learn.microsoft.com/en-us/azure/cosmos-db/gen-ai/full-text-search">Full-text search in Azure Cosmos DB for NoSQL</see> for more information.
+    /// </summary>
+    /// <param name="index">The index.</param>
+    /// <param name="value">The value indicating whether the index is configured for Full-text search.</param>
+    /// <param name="fromDataAnnotation">Indicates whether the configuration was specified using a data annotation.</param>
+    /// <returns>The configured value.</returns>
+    [Experimental(EFDiagnostics.CosmosFullTextSearchExperimental)]
+    public static string? SetFullTextIndex(
+        this IConventionIndex index,
+        bool? value,
+        bool fromDataAnnotation = false)
+        => (string?)index.SetAnnotation(
+            CosmosAnnotationNames.FullTextIndex,
+            value,
+            fromDataAnnotation)?.Value;
+
+    /// <summary>
+    ///     Returns the <see cref="ConfigurationSource" /> for whether the <see cref="IsFullTextIndex" />.
+    /// </summary>
+    /// <param name="property">The property.</param>
+    /// <returns>The <see cref="ConfigurationSource" /> for whether the index is clustered.</returns>
+
+    [Experimental(EFDiagnostics.CosmosFullTextSearchExperimental)]
+    public static ConfigurationSource? IsFullTextIndexConfigurationSource(this IConventionIndex property)
+        => property.FindAnnotation(CosmosAnnotationNames.FullTextIndex)?.GetConfigurationSource();
 }

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

@@ -243,4 +243,95 @@ private static CosmosVectorType CreateVectorType(DistanceFunction distanceFuncti
             ? new CosmosVectorType(distanceFunction, dimensions)
             : throw new ArgumentException(
                 CoreStrings.InvalidEnumValue(distanceFunction, nameof(distanceFunction), typeof(DistanceFunction)));
+
+    /// <summary>
+    ///     Configures the property to be used with a full-text search.
+    /// </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="propertyBuilder">The builder for the property being configured.</param>
+    /// <param name="language">The language for the full-text search.</param>
+    /// <returns>The same builder instance so that multiple calls can be chained.</returns>
+    [Experimental(EFDiagnostics.CosmosFullTextSearchExperimental)]
+    public static PropertyBuilder IsFullText(
+        this PropertyBuilder propertyBuilder,
+        string language = "en-US")
+    {
+        propertyBuilder.Metadata.SetFullTextSearchLanguage(language);
+        return propertyBuilder;
+    }
+
+    /// <summary>
+    ///     Configures the property to enable Full-text search for Azure Cosmos DB using a specified language.
+    /// </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>
+    /// <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>
+    /// <typeparam name="TProperty">The type of the property being configured.</typeparam>
+    /// <param name="propertyBuilder">The builder for the property being configured.</param>
+    /// <param name="language">The language for the full-text search.</param>
+    /// <returns>The same builder instance so that multiple calls can be chained.</returns>
+    [Experimental(EFDiagnostics.CosmosFullTextSearchExperimental)]
+    public static PropertyBuilder<TProperty> IsFullText<TProperty>(
+        this PropertyBuilder<TProperty> propertyBuilder,
+        string language = "en-US")
+        => (PropertyBuilder<TProperty>)IsFullText((PropertyBuilder)propertyBuilder, language);
+
+    /// <summary>
+    ///     Configures the property to enable Full-text search for Azure Cosmos DB using a specified language.
+    /// </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="propertyBuilder">The builder for the property being configured.</param>
+    /// <param name="language">The language for the full-text search.</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 IConventionPropertyBuilder? IsFullText(
+        this IConventionPropertyBuilder propertyBuilder,
+        string language,
+        bool fromDataAnnotation = false)
+    {
+        if (!propertyBuilder.CanSetIsFullText(language, fromDataAnnotation))
+        {
+            return null;
+        }
+
+        propertyBuilder.Metadata.SetFullTextSearchLanguage(language, fromDataAnnotation);
+
+        return propertyBuilder;
+    }
+
+    /// <summary>
+    ///     Returns a value indicating whether the Full-text search language can be set.
+    /// </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="propertyBuilder">The builder for the property being configured.</param>
+    /// <param name="language">The language for the full-text search.</param>
+    /// <param name="fromDataAnnotation">Indicates whether the configuration was specified using a data annotation.</param>
+    /// <returns><see langword="true" /> if the vector type can be set.</returns>
+    [Experimental(EFDiagnostics.CosmosFullTextSearchExperimental)]
+    public static bool CanSetIsFullText(
+        this IConventionPropertyBuilder propertyBuilder,
+        string language,
+        bool fromDataAnnotation = false)
+        => propertyBuilder.CanSetAnnotation(
+            CosmosAnnotationNames.FullTextSearchLanguage,
+            language,
+            fromDataAnnotation);
 }