feat: support [Column] (#85)

* implement model

* merge main

* support [column] attribute

* fix indents

* fix indent x2

* rollback

* fix `GetLocation(attributeName)` logic

* Update DAP043.md

* Update DAP042.md

* Update DAP043.md

* Update Inspection.cs

* add attr usage

---------

Co-authored-by: Marc Gravell <marc.gravell@gmail.com>

docs/rules/DAP042.md

@@ -0,0 +1,41 @@
+# DAP042
+
+Usage of [`[Column]`](https://learn.microsoft.com/dotnet/api/system.componentmodel.dataannotations.schema.columnattribute)
+attribute and `[DbValue]` attributes are conflicting - Dapper will choose either one or another's name override.
+
+This conflict can lead to unexpected behavior, so we recommend to use only one of them.
+
+Bad:
+
+``` csharp
+class MyType
+{
+    [DbValue(Name = "MyOtherOtherName")]
+    [UseColumnAttribute]
+    [Column("MyOtherName")]
+    public int MyThisName { get; set; }
+}
+```
+
+Good:
+
+``` csharp
+class MyType
+{
+    [DbValue(Name = "MyOtherOtherName")]
+    // without [Column] and [UseColumnAttribute]
+    public int MyThisName { get; set; }
+}
+```
+
+Another good:
+
+``` csharp
+class MyType
+{
+    // without [DbValue]
+    [UseColumnAttribute]
+    [Column("MyOtherName")]
+    public int MyThisName { get; set; }
+}
+```

docs/rules/DAP043.md

@@ -0,0 +1,28 @@
+# DAP043
+
+If you are looking at `DAP043`, then most probably you wanted to use [`[Column]`](https://learn.microsoft.com/dotnet/api/system.componentmodel.dataannotations.schema.columnattribute)
+attribute to override the name of the type member.
+
+However, due to [historical reasons](https://stackoverflow.com/a/77073456) you need to add a "marker attribute" `[UseColumnAttribute]`
+to explicitly let Dapper know you want to override the type member's name.
+
+Bad:
+
+``` csharp
+class MyType
+{
+    [Column("MyOtherName")]
+    public int MyThisName { get; set; }
+}
+```
+
+Good:
+
+``` csharp
+class MyType
+{
+    [UseColumnAttribute]
+    [Column("MyOtherName")]
+    public int MyThisName { get; set; }
+}
+```

src/Dapper.AOT.Analyzers/CodeAnalysis/DapperAnalyzer.Diagnostics.cs

@@ -49,6 +49,8 @@ public static readonly DiagnosticDescriptor
         ValueTypeSingleFirstOrDefaultUsage = LibraryWarning("DAP038", "Value-type single row 'OrDefault' usage", "Type '{0}' is a value-type; it will not be trivial to identify missing rows from {1}"),
         FactoryMethodMultipleExplicit = LibraryError("DAP039", "Multiple explicit factory methods", "Only one factory method should be marked [ExplicitConstructor] for type '{0}'"),
         ConstructorOverridesFactoryMethod = LibraryWarning("DAP041", "Constructor overrides factory method", "Type '{0}' has both constructor and factory method; Constructor will be used instead of a factory method"),
+        ParameterNameOverrideConflict = LibraryWarning("DAP042", "Parameter name override conflict", "A column name is specified via both [DbValue] and [Column]; '{0}' will be used"),
+        UseColumnAttributeNotSpecified = LibraryWarning("DAP043", "[Column] has no effect", "Attach the [UseColumnAttribute] attribute to make Dapper consider [Column]"),
 
         // SQL parse specific
         GeneralSqlError = SqlWarning("DAP200", "SQL error", "SQL error: {0}"),

src/Dapper.AOT.Analyzers/CodeAnalysis/DapperAnalyzer.cs

@@ -197,6 +197,14 @@ private void ValidateDapperMethod(in OperationAnalysisContext ctx, IOperation sq
                 var resultMap = MemberMap.CreateForResults(resultType, location);
                 if (resultMap is not null)
                 {
+                    if (resultMap.Members.Length != 0)
+                    {
+                        foreach (var member in resultMap.Members)
+                        {
+                            ValidateMember(member, onDiagnostic);
+                        }
+                    }
+
                     // check for single-row value-type usage
                     if (flags.HasAny(OperationFlags.SingleRow) && !flags.HasAny(OperationFlags.AtLeastOne)
                         && resultMap.ElementType.IsValueType && !CouldBeNullable(resultMap.ElementType))
@@ -817,6 +825,28 @@ enum ParameterMode
             ? null : new(rowCountHint, rowCountHintMember?.Member.Name, batchSize, cmdProps);
     }
 
+    static void ValidateMember(ElementMember member, Action<Diagnostic>? reportDiagnostic)
+    {
+        ValidateColumnAttribute();
+
+        void ValidateColumnAttribute()
+        {
+            if (member.HasDbValueAttribute && member.ColumnAttributeData.IsCorrectUsage)
+            {
+                reportDiagnostic?.Invoke(Diagnostic.Create(Diagnostics.ParameterNameOverrideConflict,
+                    location: member.GetLocation(Types.DbValueAttribute),
+                    additionalLocations: member.AsAdditionalLocations(Types.ColumnAttribute, allowNonDapperLocations: true),
+                    messageArgs: member.DbName));
+            }
+            if (member.ColumnAttributeData.ColumnAttribute == ColumnAttributeData.ColumnAttributeState.Specified
+                && member.ColumnAttributeData.UseColumnAttribute == ColumnAttributeData.UseColumnAttributeState.NotSpecified)
+            {
+                reportDiagnostic?.Invoke(Diagnostic.Create(Diagnostics.UseColumnAttributeNotSpecified,
+                    location: member.GetLocation(Types.ColumnAttribute, allowNonDapperLocations: true)));
+            }
+        }
+    }
+
     internal static ImmutableArray<ElementMember>? SharedGetParametersToInclude(MemberMap? map, ref OperationFlags flags, string? sql, Action<Diagnostic>? reportDiagnostic, out SqlParseOutputFlags parseFlags)
     {
         SortedDictionary<string, ElementMember>? byDbName = null;

src/Dapper.AOT.Analyzers/Internal/Inspection.cs

@@ -155,6 +155,22 @@ public static bool IsDapperAttribute(AttributeData attrib)
             }
         };
 
+    public static AttributeData? GetAttribute(ISymbol? symbol, string attributeName)
+    {
+        if (symbol is not null)
+        {
+            foreach (var attrib in symbol.GetAttributes())
+            {
+                if (attrib.AttributeClass!.Name == attributeName)
+                {
+                    return attrib;
+                }
+            }
+        }
+
+        return null;
+    }
+
     public static AttributeData? GetDapperAttribute(ISymbol? symbol, string attributeName)
     {
         if (symbol is not null)
@@ -404,15 +420,33 @@ public enum ElementMemberKind
     }
     public readonly struct ElementMember
     {
-        public Location[]? AsAdditionalLocations(string? attributeName = null)
+        public Location[]? AsAdditionalLocations(string? attributeName = null, bool allowNonDapperLocations = false)
         {
-            var loc = GetLocation(attributeName);
+            var loc = GetLocation(attributeName, allowNonDapperLocations);
             return loc is null ? null : [loc];
         }
 
         private readonly AttributeData? _dbValue;
-        public string DbName => TryGetAttributeValue(_dbValue, "Name", out string? name)
-            && !string.IsNullOrWhiteSpace(name) ? name!.Trim() : CodeName;
+        public readonly ColumnAttributeData ColumnAttributeData { get; } = ColumnAttributeData.Default;
+        public string DbName
+        {
+            get
+            {      
+                if (TryGetAttributeValue(_dbValue, "Name", out string? name) && !string.IsNullOrWhiteSpace(name))
+                {
+                    // priority 1: [DbValue] attribute
+                    return name!.Trim();
+                }
+
+                if (ColumnAttributeData.IsCorrectUsage)
+                {
+                    // priority 2: [Column] attribute
+                    return ColumnAttributeData.Name!;
+                }
+
+                return CodeName;
+            }
+        }
         public string CodeName => Member.Name;
         public ISymbol Member { get; }
         public ITypeSymbol CodeType => Member switch
@@ -486,13 +520,15 @@ public enum ElementMemberFlags
         public ElementMember(
             ISymbol member,
             AttributeData? dbValue,
+            ColumnAttributeData columnAttributeData,
             ElementMemberKind kind,
             ElementMemberFlags flags,
             int? constructorParameterOrder,
             int? factoryMethodParameterOrder)
         {
             _dbValue = dbValue;
             _flags = flags;
+            ColumnAttributeData = columnAttributeData;
 
             Member = member;
             Kind = kind;
@@ -518,11 +554,51 @@ public override bool Equals(object obj) => obj is ElementMember other
             }
             return null;
         }
-        public Location? GetLocation(string? attributeName = null)
+        public Location? GetLocation(string? attributeName = null, bool allowNonDapperLocations = false)
+        {
+            if (attributeName is null)
+            {
+                return GetLocation();
+            }
+
+            var result = allowNonDapperLocations
+                ? GetAttribute(Member, attributeName)?.ApplicationSyntaxReference?.GetSyntax()?.GetLocation()
+                : GetDapperAttribute(Member, attributeName)?.ApplicationSyntaxReference?.GetSyntax()?.GetLocation();
+
+            return result ?? GetLocation();
+        }
+    }
+
+    internal struct ColumnAttributeData
+    {
+        public UseColumnAttributeState UseColumnAttribute { get; }
+        public ColumnAttributeState ColumnAttribute { get; }
+        public string? Name { get; }
+
+        public ColumnAttributeData(UseColumnAttributeState useColumnAttribute, ColumnAttributeState columnAttribute, string? name)
+        {
+            UseColumnAttribute = useColumnAttribute;
+            ColumnAttribute = columnAttribute;
+            Name = name;
+        }
+
+        public bool IsCorrectUsage 
+            => UseColumnAttribute is UseColumnAttributeState.NotSpecified or UseColumnAttributeState.Enabled
+            && ColumnAttribute is ColumnAttributeState.Specified && !string.IsNullOrEmpty(Name);
+
+        public static ColumnAttributeData Default => new(UseColumnAttributeState.NotSpecified, ColumnAttributeState.NotSpecified, null);
+
+        public enum UseColumnAttributeState
+        {
+            NotSpecified,
+            Disabled,
+            Enabled
+        }
+
+        public enum ColumnAttributeState
         {
-            var loc = attributeName is null ? null :
-                GetDapperAttribute(Member, attributeName)?.ApplicationSyntaxReference?.GetSyntax()?.GetLocation();
-            return loc ?? GetLocation();
+            NotSpecified,
+            Specified
         }
     }
 
@@ -775,12 +851,55 @@ internal static ImmutableArray<ElementMember> GetMembers(bool forParameters, ITy
                     flags |= ElementMember.ElementMemberFlags.IsExpandable;
                 }
 
+                var columnAttributeData = ParseColumnAttributeData(member);
+
                 // all good, then!
-                builder.Add(new(member, dbValue, kind, flags, constructorParameterOrder, factoryMethodParamOrder));
+                builder.Add(new(member, dbValue, columnAttributeData, kind, flags, constructorParameterOrder, factoryMethodParamOrder));
             }
             return builder.ToImmutable();
         }
 
+        static ColumnAttributeData ParseColumnAttributeData(ISymbol? member)
+        {
+            if (member is null) return ColumnAttributeData.Default;
+            var useColumnAttributeState = ParseUseColumnAttributeState();
+            var (columnAttributeState, columnName) = ParseColumnAttributeState();
+
+            return new ColumnAttributeData(useColumnAttributeState, columnAttributeState, columnName);
+
+            (ColumnAttributeData.ColumnAttributeState state, string? columnName) ParseColumnAttributeState()
+            {
+                var columnAttribute = GetAttribute(member, Types.ColumnAttribute);
+                if (columnAttribute is null) return (ColumnAttributeData.ColumnAttributeState.NotSpecified, null);
+
+                if (TryGetAttributeValue(columnAttribute, "name", out string? name) && !string.IsNullOrWhiteSpace(name))
+                {
+                    return (ColumnAttributeData.ColumnAttributeState.Specified, name);
+                }
+                else
+                {
+                    // [Column] is specified, but value is null. Can happen for ctor overload: 
+                    // https://learn.microsoft.com/en-us/dotnet/api/system.componentmodel.dataannotations.schema.columnattribute.-ctor?view=net-7.0#system-componentmodel-dataannotations-schema-columnattribute-ctor
+                    return (ColumnAttributeData.ColumnAttributeState.Specified, null);
+                }
+            }
+            ColumnAttributeData.UseColumnAttributeState ParseUseColumnAttributeState()
+            {
+                var useColumnAttribute = GetDapperAttribute(member, Types.UseColumnAttributeAttribute);
+                if (useColumnAttribute is null) return ColumnAttributeData.UseColumnAttributeState.NotSpecified;
+
+                if (TryGetAttributeValue(useColumnAttribute, "enable", out bool useColumnAttributeState))
+                {
+                    return useColumnAttributeState ? ColumnAttributeData.UseColumnAttributeState.Enabled : ColumnAttributeData.UseColumnAttributeState.Disabled;
+                }
+                else
+                {
+                    // default
+                    return ColumnAttributeData.UseColumnAttributeState.Enabled;
+                }
+            }
+        }
+
         static IReadOnlyDictionary<string, MethodParameter> ParseMethodParameters(IMethodSymbol constructorSymbol)
         {
             var parameters = new Dictionary<string, MethodParameter>(StringComparer.InvariantCultureIgnoreCase);
@@ -814,7 +933,7 @@ private static bool TryGetAttributeValue<T>(AttributeData? attrib, string name,
                 int index = 0;
                 foreach (var p in ctor.Parameters)
                 {
-                    if (StringComparer.InvariantCultureIgnoreCase.Equals(p.Name == name))
+                    if (StringComparer.InvariantCultureIgnoreCase.Equals(p.Name, name))
                     {
                         value = Parse(attrib.ConstructorArguments[index], out isNull);
                         return true;

src/Dapper.AOT.Analyzers/Internal/Types.cs

@@ -6,6 +6,8 @@ public const string
         BindTupleByNameAttribute = nameof(BindTupleByNameAttribute),
         DapperAotAttribute = nameof(DapperAotAttribute),
         DbValueAttribute = nameof(DbValueAttribute),
+        ColumnAttribute = nameof(ColumnAttribute),
+        UseColumnAttributeAttribute = nameof(UseColumnAttributeAttribute),
         RowCountAttribute = nameof(RowCountAttribute),
         CacheCommandAttribute = nameof(CacheCommandAttribute),
         IncludeLocationAttribute = nameof(IncludeLocationAttribute),

src/Dapper.AOT/UseColumnAttributeAttribute.cs

@@ -0,0 +1,16 @@
+using System;
+
+namespace Dapper
+{
+    /// <summary>
+    /// Specifies whether to use [System.ComponentModel.DataAnnotations.Schema.ColumnAttribute] for additional behavioral configuration
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Property | AttributeTargets.Field, AllowMultiple = false)]
+    public class UseColumnAttributeAttribute : Attribute
+    {
+        /// <param name="enable">enable usage of [Column] attribute</param>
+        public UseColumnAttributeAttribute(bool enable = true)
+        {
+        }
+    }
+}

test/Dapper.AOT.Test/Dapper.AOT.Test.csproj

@@ -36,6 +36,7 @@
         <PackageReference Include="Npgsql" />
         <PackageReference Include="Oracle.ManagedDataAccess" Condition="'$(TargetFramework)'=='net48'" />
         <PackageReference Include="Oracle.ManagedDataAccess.Core" Condition="'$(TargetFramework)'!='net48'" />
+        <PackageReference Include="System.ComponentModel.Annotations" />
         <PackageReference Include="System.Data.Common" />
         <PackageReference Include="System.Data.SqlClient" />
         <PackageReference Include="Microsoft.Data.SqlClient" />

test/Dapper.AOT.Test/Interceptors/ColumnAttribute.input.cs

@@ -0,0 +1,41 @@
+using Dapper;
+using System.Data.Common;
+
+// needed for [Column] attribute
+using System.ComponentModel.DataAnnotations.Schema;
+
+[module: DapperAot]
+
+public static class Foo
+{
+    static void SomeCode(DbConnection connection, string bar, bool isBuffered)
+    {
+        _ = connection.Query<MyType>("def");
+    }
+
+    public class MyType
+    {
+        // default
+        public int A { get; set; }
+
+        // dbvalue
+        [DbValue(Name = "DbValue_B")]
+        public int B { get; set; }
+
+        // standard enabled
+        [UseColumnAttribute]
+        [Column("StandardColumn_C")]
+        public int C { get; set; }
+
+        // explicitly enabled
+        [UseColumnAttribute]
+        [Column("ExplicitColumn_D")]
+        public int D { get; set; }
+
+        // dbValue & Column enabled
+        [UseColumnAttribute]
+        [DbValue(Name = "DbValue_E")]
+        [Column("Column_E")]
+        public int E { get; set; }
+    }
+}