Add inference-based overload to ForNpgsqlHasEnum

doc/mapping/enum.md

@@ -9,9 +9,8 @@ However, the Npgsql provider also allows you to map your CLR enums to [database
 First, you must specify the PostgreSQL enum type on your model, just like you would with tables, sequences or other databases objects:
 
 ```c#
-protected override void OnModelCreating(ModelBuilder builder) {
-    builder.ForNpgsqlHasEnum("Mood", new[] { "happy", "sad" });
-}
+protected override void OnModelCreating(ModelBuilder builder)
+    => builder.ForNpgsqlHasEnum<Mood>();
 ```
 
 This causes the EF Core provider to create your data enum type, `Mood`, with two labels: `happy` and `sad`. This will cause the appropriate migration to be created.
@@ -22,9 +21,7 @@ Even if your database enum is created, Npgsql has to know about it, and especial
 
 ```c#
 static MyDbContext()
-{
-    NpgsqlConnection.GlobalTypeMapper.MapEnum<Mood>("Mood");
-}
+    => NpgsqlConnection.GlobalTypeMapper.MapEnum<Mood>();
 ```
 
 This code lets Npgsql know that your CLR enum type, `Mood`, should be mapped to a database enum called `Mood`.

src/EFCore.PG.NTS/EFCore.PG.NTS.csproj

@@ -27,6 +27,6 @@
   </ItemGroup>
   <ItemGroup>
     <PackageReference Include="Npgsql.NetTopologySuite" Version="1.0.2" />
-    <PackageReference Include="Npgsql" Version="4.0.3-ci.1170+sha.c6c404330" />
+    <PackageReference Include="Npgsql" Version="4.0.3-ci.1272+sha.b3fc7da6f" />
   </ItemGroup>
 </Project>

src/EFCore.PG.NodaTime/EFCore.PG.NodaTime.csproj

@@ -26,7 +26,7 @@
     <ProjectReference Include="..\EFCore.PG\EFCore.PG.csproj" />
   </ItemGroup>
   <ItemGroup>
-    <PackageReference Include="Npgsql" Version="4.0.3-ci.1170+sha.c6c404330" />
+    <PackageReference Include="Npgsql" Version="4.0.3-ci.1272+sha.b3fc7da6f" />
     <PackageReference Include="Npgsql.NodaTime" Version="1.0.0" />
   </ItemGroup>
 </Project>

src/EFCore.PG/EFCore.PG.csproj

@@ -25,7 +25,7 @@
     <PackageReference Include="Microsoft.EntityFrameworkCore" Version="2.2.0-preview1-34941" PrivateAssets="none" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Relational" Version="2.2.0-preview1-34941" PrivateAssets="none" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Abstractions" Version="2.2.0-preview1-34941" PrivateAssets="none" />
-    <PackageReference Include="Npgsql" Version="4.0.3-ci.1170+sha.c6c404330" />
+    <PackageReference Include="Npgsql" Version="4.0.3-ci.1272+sha.b3fc7da6f" />
   </ItemGroup>
   <ItemGroup>
     <None Update="Properties\NpgsqlStrings.Designer.tt">

src/EFCore.PG/Extensions/NpgsqlModelBuilderExtensions.cs

@@ -1,24 +1,58 @@
-using JetBrains.Annotations;
+#region License
+
+// The PostgreSQL License
+//
+// Copyright (C) 2016 The Npgsql Development Team
+//
+// Permission to use, copy, modify, and distribute this software and its
+// documentation for any purpose, without fee, and without a written
+// agreement is hereby granted, provided that the above copyright notice
+// and this paragraph and the following two paragraphs appear in all copies.
+//
+// IN NO EVENT SHALL THE NPGSQL DEVELOPMENT TEAM BE LIABLE TO ANY PARTY
+// FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES,
+// INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
+// DOCUMENTATION, EVEN IF THE NPGSQL DEVELOPMENT TEAM HAS BEEN ADVISED OF
+// THE POSSIBILITY OF SUCH DAMAGE.
+//
+// THE NPGSQL DEVELOPMENT TEAM SPECIFICALLY DISCLAIMS ANY WARRANTIES,
+// INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
+// ON AN "AS IS" BASIS, AND THE NPGSQL DEVELOPMENT TEAM HAS NO OBLIGATIONS
+// TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+
+#endregion
+
+using System;
+using System.Linq;
+using System.Reflection;
+using JetBrains.Annotations;
 using Microsoft.EntityFrameworkCore.Metadata;
+using Npgsql;
 using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
 using Npgsql.EntityFrameworkCore.PostgreSQL.Utilities;
+using Npgsql.NameTranslation;
+using NpgsqlTypes;
 
 // ReSharper disable once CheckNamespace
 namespace Microsoft.EntityFrameworkCore
 {
     /// <summary>
-    ///     Npgsql specific extension methods for <see cref="ModelBuilder" />.
+    /// Npgsql specific extension methods for <see cref="ModelBuilder"/>.
     /// </summary>
+    [PublicAPI]
     public static class NpgsqlModelBuilderExtensions
     {
+        #region Sequences
+
         /// <summary>
-        ///     Configures the model to use a sequence-based hi-lo pattern to generate values for properties
-        ///     marked as <see cref="ValueGenerated.OnAdd" />, when targeting PostgreSQL.
+        /// Configures the model to use a sequence-based hi-lo pattern to generate values for properties
+        /// marked as <see cref="ValueGenerated.OnAdd" />, when targeting PostgreSQL.
         /// </summary>
-        /// <param name="modelBuilder"> The model builder. </param>
-        /// <param name="name"> The name of the sequence. </param>
-        /// <param name="schema">The schema of the sequence. </param>
-        /// <returns> The same builder instance so that multiple calls can be chained. </returns>
+        /// <param name="modelBuilder">The model builder.</param>
+        /// <param name="name">The name of the sequence.</param>
+        /// <param name="schema">The schema of the sequence.</param>
+        /// <returns>The same builder instance so that multiple calls can be chained.</returns>
         public static ModelBuilder ForNpgsqlUseSequenceHiLo(
             [NotNull] this ModelBuilder modelBuilder,
             [CanBeNull] string name = null,
@@ -45,12 +79,12 @@ public static ModelBuilder ForNpgsqlUseSequenceHiLo(
         }
 
         /// <summary>
-        ///     Configures the model to use the PostgreSQL SERIAL feature to generate values for properties
-        ///     marked as <see cref="ValueGenerated.OnAdd" />, when targeting PostgreSQL. This is the default
-        ///     behavior when targeting PostgreSQL.
+        /// Configures the model to use the PostgreSQL SERIAL feature to generate values for properties
+        /// marked as <see cref="ValueGenerated.OnAdd" />, when targeting PostgreSQL. This is the default
+        /// behavior when targeting PostgreSQL.
         /// </summary>
-        /// <param name="modelBuilder"> The model builder. </param>
-        /// <returns> The same builder instance so that multiple calls can be chained. </returns>
+        /// <param name="modelBuilder">The model builder.</param>
+        /// <returns>The same builder instance so that multiple calls can be chained.</returns>
         public static ModelBuilder ForNpgsqlUseSerialColumns(
             [NotNull] this ModelBuilder modelBuilder)
         {
@@ -65,6 +99,8 @@ public static ModelBuilder ForNpgsqlUseSerialColumns(
             return modelBuilder;
         }
 
+        #endregion
+
         #region Identity
 
         /// <summary>
@@ -134,6 +170,8 @@ public static ModelBuilder ForNpgsqlUseIdentityColumns(
 
         #endregion Identity
 
+        #region Extensions
+
         public static ModelBuilder HasPostgresExtension(
             [NotNull] this ModelBuilder modelBuilder,
             [NotNull] string name)
@@ -145,6 +183,25 @@ public static ModelBuilder HasPostgresExtension(
             return modelBuilder;
         }
 
+        #endregion
+
+        #region Enums
+
+        /// <summary>
+        /// Registers a user-defined enum type in the model.
+        /// </summary>
+        /// <param name="modelBuilder">The model builder in which to create the enum type.</param>
+        /// <param name="schema">The schema in which to create the enum type.</param>
+        /// <param name="name">The name of the enum type to create.</param>
+        /// <param name="labels">The enum label values.</param>
+        /// <returns>
+        /// The updated <see cref="ModelBuilder"/>.
+        /// </returns>
+        /// <remarks>
+        /// See: https://www.postgresql.org/docs/current/static/datatype-enum.html
+        /// </remarks>
+        /// <exception cref="ArgumentNullException">builder</exception>
+        [NotNull]
         public static ModelBuilder ForNpgsqlHasEnum(
             [NotNull] this ModelBuilder modelBuilder,
             [CanBeNull] string schema,
@@ -159,12 +216,64 @@ public static ModelBuilder ForNpgsqlHasEnum(
             return modelBuilder;
         }
 
+        /// <summary>
+        /// Registers a user-defined enum type in the model.
+        /// </summary>
+        /// <param name="modelBuilder">The model builder in which to create the enum type.</param>
+        /// <param name="name">The name of the enum type to create.</param>
+        /// <param name="labels">The enum label values.</param>
+        /// <returns>
+        /// The updated <see cref="ModelBuilder"/>.
+        /// </returns>
+        /// <remarks>
+        /// See: https://www.postgresql.org/docs/current/static/datatype-enum.html
+        /// </remarks>
+        /// <exception cref="ArgumentNullException">builder</exception>
+        [NotNull]
         public static ModelBuilder ForNpgsqlHasEnum(
             [NotNull] this ModelBuilder modelBuilder,
             [NotNull] string name,
             [NotNull] string[] labels)
             => modelBuilder.ForNpgsqlHasEnum(null, name, labels);
 
+        /// <summary>
+        /// Registers a user-defined enum type in the model.
+        /// </summary>
+        /// <param name="modelBuilder">The model builder in which to create the enum type.</param>
+        /// <param name="schema">The schema in which to create the enum type.</param>
+        /// <param name="name">The name of the enum type to create.</param>
+        /// <param name="nameTranslator">
+        /// The translator for name and label inference.
+        /// Defaults to <see cref="NpgsqlSnakeCaseNameTranslator"/>.</param>
+        /// <typeparam name="TEnum"></typeparam>
+        /// <returns>
+        /// The updated <see cref="ModelBuilder"/>.
+        /// </returns>
+        /// <remarks>
+        /// See: https://www.postgresql.org/docs/current/static/datatype-enum.html
+        /// </remarks>
+        /// <exception cref="ArgumentNullException">builder</exception>
+        [NotNull]
+        public static ModelBuilder ForNpgsqlHasEnum<TEnum>(
+            [NotNull] this ModelBuilder modelBuilder,
+            [CanBeNull] string schema = null,
+            [CanBeNull] string name = null,
+            [CanBeNull] INpgsqlNameTranslator nameTranslator = null)
+            where TEnum : struct, Enum
+        {
+            if (nameTranslator == null)
+                nameTranslator = NpgsqlConnection.GlobalTypeMapper.DefaultNameTranslator;
+
+            return modelBuilder.ForNpgsqlHasEnum(
+                schema,
+                name ?? GetTypePgName<TEnum>(nameTranslator),
+                GetMemberPgNames<TEnum>(nameTranslator));
+        }
+
+        #endregion
+
+        #region Templates
+
         public static ModelBuilder HasDatabaseTemplate(
             [NotNull] this ModelBuilder modelBuilder,
             [NotNull] string templateDatabaseName)
@@ -176,6 +285,10 @@ public static ModelBuilder HasDatabaseTemplate(
             return modelBuilder;
         }
 
+        #endregion
+
+        #region Ranges
+
         /// <summary>
         /// Registers a user-defined range type in the model.
         /// </summary>
@@ -238,6 +351,10 @@ public static ModelBuilder ForNpgsqlHasRange(
             [NotNull] string subtype)
             => ForNpgsqlHasRange(modelBuilder, null, name, subtype);
 
+        #endregion
+
+        #region Tablespaces
+
         public static ModelBuilder ForNpgsqlUseTablespace(
             [NotNull] this ModelBuilder modelBuilder,
             [NotNull] string tablespace)
@@ -248,5 +365,27 @@ public static ModelBuilder ForNpgsqlUseTablespace(
             modelBuilder.Model.Npgsql().Tablespace = tablespace;
             return modelBuilder;
         }
+
+        #endregion
+
+        #region Helpers
+
+        // See: https://github.com/npgsql/npgsql/blob/dev/src/Npgsql/TypeMapping/TypeMapperBase.cs#L132-L138
+        [NotNull]
+        static string GetTypePgName<TEnum>([NotNull] INpgsqlNameTranslator nameTranslator) where TEnum : struct, Enum
+            => typeof(TEnum).GetCustomAttribute<PgNameAttribute>()?.PgName ??
+               nameTranslator.TranslateTypeName(typeof(TEnum).Name);
+
+        // See: https://github.com/npgsql/npgsql/blob/dev/src/Npgsql/TypeHandlers/EnumHandler.cs#L118-L129
+        [NotNull]
+        [ItemNotNull]
+        static string[] GetMemberPgNames<TEnum>([NotNull] INpgsqlNameTranslator nameTranslator) where TEnum : struct, Enum
+            => typeof(TEnum)
+               .GetFields(BindingFlags.Static | BindingFlags.Public)
+               .Select(x => x.GetCustomAttribute<PgNameAttribute>()?.PgName ??
+                            nameTranslator.TranslateMemberName(x.Name))
+               .ToArray();
+
+        #endregion
     }
 }

test/EFCore.PG.FunctionalTests/EFCore.PG.FunctionalTests.csproj

@@ -26,5 +26,6 @@
     <PackageReference Include="Microsoft.EntityFrameworkCore.Relational.Specification.Tests" Version="2.2.0-preview1-34941" />
     <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="2.2.0-preview1-34941" />
     <PackageReference Include="Microsoft.Extensions.Configuration.EnvironmentVariables" Version="2.2.0-preview1-34941" />
+    <PackageReference Update="Npgsql" Version="4.0.3-ci.1272" />
   </ItemGroup>
 </Project>