Pragmatic.Mapping - Feature Matrix

Tracks the implemented and tested features. Every cell is a combination that MUST be supported and tested.

Test Summary: see Pragmatic.Mapping.Tests and Pragmatic.Mapping.EFCore.Tests (Mapping 291 tests + the EFCore Postgres suite)

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Legend

Symbol	Meaning
✅	Implemented & Tested
⚠️	Implemented, needs fix
❌	Not implemented
🔲	Planned

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1. Type Kinds (DTO Type)

Type Kind	FromEntity	ToEntity	Projection	Test File
class	✅	✅	✅	NullableAndNestedGeneratorTests.PartialClass_GeneratesCorrectly
record	✅	✅	✅	BasicMappingGeneratorTests
struct	✅	🔲	🔲	NullableAndNestedGeneratorTests.PartialStruct_GeneratesCorrectly
record struct	✅	🔲	🔲	BasicMappingGeneratorTests.MapFrom_RecordStruct_GeneratesCorrectly

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2. Source Type Kinds (Entity Type)

Source Type Kind	Support	Test
class	✅	All basic tests
record	✅	-
struct	✅	NullableAndNestedGeneratorTests.PartialStruct_GeneratesCorrectly
record struct	✅	-

Note: Null check skipped for value types (structs can’t be null).

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3. Property Types

3.1 Simple Types

Type	Direct Mapping	Test
int	✅	BasicMappingGeneratorTests
int?	✅	NullableAndNestedGeneratorTests.NullableInt_MapsDirectly
string	✅	Multiple tests
string?	✅	NullableAndNestedGeneratorTests.NullableString_MapsDirectly
decimal	✅	NullableAndNestedGeneratorTests.PartialClass_GeneratesCorrectly
DateTime	✅	-
DateTime?	✅	NullableAndNestedGeneratorTests.NullableDateTime_MapsDirectly
Guid	✅	-
Guid?	✅	TypeConversionGeneratorTests.NullableGuid_MapsDirectly
DateOnly	✅	TypeConversionGeneratorTests.DateOnly_MapsDirectly
TimeOnly	✅	TypeConversionGeneratorTests.DateOnly_MapsDirectly
DateOnly?	✅	TypeConversionGeneratorTests.NullableDateOnly_MapsDirectly
TimeOnly?	✅	TypeConversionGeneratorTests.NullableDateOnly_MapsDirectly
enum	✅	TypeConversionGeneratorTests.Enum_SameType_MapsDirectly
enum?	✅	TypeConversionGeneratorTests.NullableEnum_MapsDirectly

3.2 Collection Types

Collection Type	Simple Element	DTO Element	Test
T[]	✅	✅	CollectionMappingGeneratorTests.ArrayOfInt, ArrayOfDto
List<T>	✅	✅	CollectionMappingGeneratorTests.ListOfString, ListOfDto
List<T>?	✅	✅	NullableListOfNullableInt, NullableListOfNullableNestedDto
IList<T>	✅	✅	CollectionMappingGeneratorTests.IListOfInt
ICollection<T>	✅	✅	CollectionMappingGeneratorTests.ICollectionOfInt
IEnumerable<T>	✅	✅	CollectionMappingGeneratorTests.IEnumerableOfInt
IReadOnlyList<T>	✅	🔲	CollectionMappingGeneratorTests.IReadOnlyListOfInt
IReadOnlyCollection<T>	✅	🔲	CollectionMappingGeneratorTests.IReadOnlyCollectionOfInt
HashSet<T>	✅	🔲	CollectionMappingGeneratorTests.HashSetOfInt

3.3 Nested DTO Types

Scenario	Status	Test
Single non-nullable DTO	✅	NullableAndNestedGeneratorTests.NestedDto_MapsWithFromEntity
Single nullable DTO	✅	NullableAndNestedGeneratorTests.NullableNestedDto_HandlesNullSafely
Array of DTO	✅	NullableAndNestedGeneratorTests.ArrayOfNestedDto_MapsEachElement
List of DTO	✅	CollectionMappingGeneratorTests.ListOfDto_MapsEachElement
List of nullable DTO	✅	NullableAndNestedGeneratorTests.NullableListOfNullableNestedDto_HandlesCorrectly

Implementation: Uses SymbolDisplayFormat.FullyQualifiedFormat for type names to avoid namespace resolution issues.

3.4 Dictionary Types

Dictionary Type	Simple Value	DTO Value	Test
Dictionary<K,V>	✅	✅	CollectionMappingGeneratorTests.DictionaryStringInt, TypeConversionGeneratorTests.DictionaryWithDtoValue
IDictionary<K,V>	🔲	🔲	-
IReadOnlyDictionary<K,V>	🔲	🔲	-

3.5 Type Conversions (Implicit/Widening)

Conversion	Status	Test
int → long	✅	TypeConversionGeneratorTests.IntToLong_ImplicitConversion
int → decimal	✅	TypeConversionGeneratorTests.IntToDecimal_ImplicitConversion
int? → int (no default)	⚠️ CS0266	TypeConversionGeneratorTests.NullableIntToInt_WithoutDefault_ShouldCompile
int? → int (with default)	✅	AdvancedMappingGeneratorTests.MapProperty_WithDefault_UsesDefaultWhenNull

Note: C# implicit conversions (widening) work automatically. Nullable → Non-nullable requires [MapProperty(Default=)].

3.6 Type Conversions (Explicit) ✅ IMPLEMENTED

Conversion	Status	Generated Code	Test
int → string	✅	.ToString()	TypeConversionGeneratorTests.IntToString
string → int	✅	int.Parse()	TypeConversionGeneratorTests.StringToInt
enum → string	✅	.ToString()	TypeConversionGeneratorTests.EnumToString
string → enum	✅	Enum.Parse<T>()	TypeConversionGeneratorTests.StringToEnum
Guid → string	✅	.ToString()	TypeConversionGeneratorTests.GuidToString
string → Guid	✅	Guid.Parse()	TypeConversionGeneratorTests.StringToGuid
DateTime → DateOnly	✅	DateOnly.FromDateTime()	TypeConversionGeneratorTests.DateTimeToDateOnly
DateOnly → DateTime	✅	.ToDateTime(TimeOnly.MinValue)	TypeConversionGeneratorTests.DateOnlyToDateTime
DateTime → TimeOnly	✅	TimeOnly.FromDateTime()	TypeConversionGeneratorTests.DateTimeToTimeOnly
decimal → string	✅	.ToString()	TypeConversionGeneratorTests.DecimalToString
string → decimal	✅	decimal.Parse()	TypeConversionGeneratorTests.StringToDecimal
bool → string	✅	.ToString()	TypeConversionGeneratorTests.BoolToString
string → bool	✅	bool.Parse()	TypeConversionGeneratorTests.StringToBool
DateTime → string	✅	.ToString()	TypeConversionGeneratorTests.DateTimeToString
string → DateTime	✅	DateTime.Parse()	TypeConversionGeneratorTests.StringToDateTime
string → DateOnly	✅	DateOnly.Parse()	TypeConversionGeneratorTests.StringToDateOnly
string → TimeOnly	✅	TimeOnly.Parse()	TypeConversionGeneratorTests.StringToTimeOnly

Implementation: Generator detects source/target type mismatch and applies known conversion patterns automatically. Nullable variants also supported (e.g., int? → string, string → int?).

3.7 Collection Type Conversions

Source → Target	Status	Test
List<T> → T[]	✅	TypeConversionGeneratorTests.ListToArray_Conversion
T[] → List<T>	✅	TypeConversionGeneratorTests.ArrayToList_Conversion
IEnumerable<T> → List<T>	✅	TypeConversionGeneratorTests.IEnumerableToList_Conversion
List<T> → IEnumerable<T>	✅	TypeConversionGeneratorTests.ListToIEnumerable_Conversion
List<T> → HashSet<T>	✅	TypeConversionGeneratorTests.ListToHashSet_Conversion
T[] → IReadOnlyList<T>	✅	TypeConversionGeneratorTests.ArrayToIReadOnlyList_Conversion

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4. Mapping Attributes

Attribute	Status	Test
[MapFrom<T>]	✅	All FromEntity tests
[MapTo<T>]	✅	AdvancedMappingGeneratorTests.MapTo_*
[MapProperty] (path / Default / Format / Target / Separator)	✅	AdvancedMappingGeneratorTests.MapProperty_*
[MapIgnore]	✅	AdvancedMappingGeneratorTests.MapIgnore_*
[MapConverter<T>] (property-level)	✅	AdvancedMappingGeneratorTests.Converter_*
[MapConverter<T>] (class-level, signature-matched)	✅	ConventionAndTypeLevelTests
[MapConstructor]	✅	MapConstructorAndSeparatorGeneratorTests
[MapCondition] (runtime gate, and projection gate for an expression-bodied predicate; PRAG0329/0332)	✅	DiagnosticTests, RuntimeDispatchTests, ADetailInOneProjectionTests
[MapDerived<TS,TD>] (polymorphic; PRAG0330/0331)	✅	DiagnosticTests, RuntimeDispatchTests
[GenerateProjection(MaxDepth=)]	✅	ProjectionGeneratorTests, DiagnosticTests (PRAG0327)
[GenerateBodyOnlyVariant]	✅	BodyOnlyVariantGeneratorTests

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5. Mapping Features

5.1 Resolution Strategies

Strategy	Status	Test
Direct name match	✅	All basic tests
Case-insensitive match	✅	-
Flattening (AddressCity → Address.City)	✅	AdvancedMappingGeneratorTests.Flattening_*
Concatenation (FullName → FirstName + LastName)	✅	BasicMappingGeneratorTests.MapFrom_WithFullNameConvention
Explicit path via [MapProperty]	✅	AdvancedMappingGeneratorTests.MapProperty_*

5.2 Special Handling

Feature	Status	Test
ID property exclusion in ToEntity	✅	AdvancedMappingGeneratorTests.MapTo_ExcludesIdByDefault
Init-only properties	✅	-
Required properties	✅	-
Circular reference detection	✅	-
Null safety	✅	NullableAndNestedGeneratorTests.*

5.3 Generated Methods

Method	Status	Struct Support	Test
FromEntity(entity)	✅	✅	All FromEntity tests
ToEntity()	✅	🔲	MapTo tests
Projection	✅	🔲	ProjectionGeneratorTests

Note: ApplyTo(entity) is generated by Pragmatic.Mapping for DTOs marked with [MapTo<T>] (updates an existing entity, partial-update semantics). It is suppressed only when the DTO also carries [Patch<T>] or [Mutation<T>], in which case the respective generator owns the update path.

5.4 Customization Hooks

Hook	Status	Test
partial void BeforeMapping()	✅	-
partial void CustomizeMapping()	✅	-
MappingContext struct	✅	-

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6. Accessibility

DTO Accessibility	Support	Extensions Class	Test
public	✅	public static	All basic tests
internal	✅	internal static	AdvancedMappingGeneratorTests.MapFrom_InternalClass_GeneratesInternalMethods
private (nested)	🔲	-	-

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7. Fixed Bugs

Bug	Status	Fix
Struct source + Ensure.ThrowIfNull	✅ FIXED	Skip null check for value types
Nullable DTO type name includes ?	✅ FIXED	Use SymbolDisplayFormat.FullyQualifiedFormat
List<string> treated as DTO collection	✅ FIXED	Check IsElementSimple in AnalyzeNestedDto
Extensions class ignores accessibility	✅ FIXED	Added ParseAccessibility() in MappingExtensionsTemplate
[MapProperty(Default=)] not implemented	✅ FIXED	Added fallback resolution by property name when only Default is specified

7.1 Recently Fixed Bugs

Issue	Status	Fix	Test
[MapProperty(Format=)] for non-DateTime	✅ FIXED	Added format support to GenerateNumericToString and GenerateToString	AdvancedMappingGeneratorTests.MapProperty_WithFormat_*
[MapProperty] + [MapConverter] together	✅ FIXED	Moved converter check before MapProperty check, passed converter to CreateExplicitMapping	AdvancedMappingGeneratorTests.MapProperty_WithMapConverter_*

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8. Test Coverage Summary

Test File	Tests	Passing	Failing
BasicMappingGeneratorTests	7	7	0
AdvancedMappingGeneratorTests	16	16	0
CollectionMappingGeneratorTests	9	9	0
ProjectionGeneratorTests	5	5	0
NullableAndNestedGeneratorTests	9	9	0
TypeConversionGeneratorTests	51	51	0
AutomaticConversionGeneratorTests	12	12	0
AutoDefaultGeneratorTests	12	12	0
DiagnosticTests	4	4	0
TOTAL	125	125	0

Note: EF Core integration tests use TestContainers with PostgreSQL.

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9. Sample Coverage

Sample File	Features Demonstrated
BasicMappingSample	FromEntity, extension methods, collection mapping, FullName concatenation, flattening
NestedMappingSample	Nested DTOs, collection of DTOs, flattened DTO
BidirectionalMappingSample	MapFrom + MapTo, ToEntity()
StructMappingSample	record struct, zero-allocation, Projection
ProjectionSample	GenerateProjection, Expression<Func<T,TDto>>
TypeConversionSample	ToString, Parse, DateTime↔DateOnly, Dictionary with DTOs, Inheritance
NullableAndAdvancedSample	Auto-default, Collection type conversions, Circular references, DateOnly→DateTime
TypeCombinationsSample	class→class, class→record, record→record, record→class, MapIgnore
AdvancedAttributesSample	MapIgnore, MapConverter, MapProperty(path), MapProperty(Format)

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10. Completed Milestones ✅

• Core source generator (FromEntity, ToEntity, Projection)
• All property types (simple, nullable, collections, nested DTOs)
• Property resolution (direct match, flattening, concatenation)
• MapProperty with Default value
• MapIgnore, MapConverter attributes
• EF Core integration package with extension methods
• Comprehensive samples (Basic, Nested, Bidirectional, Struct, Projection, TypeConversion)
• README documentation
• P0: Auto-default for primitives (GetValueOrDefault, ?? “”)
• P1: Type conversions (ToString, Parse, enum↔string, Guid↔string)
• P2: DateTime conversions (DateTime↔DateOnly/TimeOnly)
• P3: Dictionary with DTO values, Inheritance mapping

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11. Priority Order for Remaining Work

P0 - Critical (MVP completeness) ✅ COMPLETE

Feature	Description	Status
Auto-default for primitives	int? → int uses GetValueOrDefault(), string? → string uses ?? ""	✅ Implemented
Auto-default in Projection	Uses ?? 0, ?? "", ?? Guid.Empty for EF Core Expression Tree compatibility	✅ Implemented

P1 - High (User experience) ✅ COMPLETE

Feature	Description	Status	Test
ToString conversions	int → string via .ToString()	✅	TypeConversionGeneratorTests.IntToString
Enum → string	Status.Active → "Active"	✅	TypeConversionGeneratorTests.EnumToString
Parse conversions	string → int via int.Parse()	✅	TypeConversionGeneratorTests.StringToInt
Guid ↔ string	Guid.ToString() / Guid.Parse()	✅	TypeConversionGeneratorTests.GuidToString/StringToGuid

P2 - Medium (Completeness) ✅ COMPLETE

Feature	Description	Status	Test
DateTime → DateOnly	DateOnly.FromDateTime()	✅	TypeConversionGeneratorTests.DateTimeToDateOnly
DateTime → TimeOnly	TimeOnly.FromDateTime()	✅	TypeConversionGeneratorTests.DateTimeToTimeOnly
DateOnly → DateTime	.ToDateTime(TimeOnly.MinValue)	✅	TypeConversionGeneratorTests.DateOnlyToDateTime
String ↔ decimal	Parse/ToString	✅	TypeConversionGeneratorTests.StringToDecimal/DecimalToString

P3 - Low (Nice to have) ✅ COMPLETE

Feature	Description	Status	Test
Dictionary with DTO values	Dictionary<string, CategoryDto>	✅	TypeConversionGeneratorTests.DictionaryWithDtoValue
Inheritance mapping	Base → Derived DTO properties	✅	TypeConversionGeneratorTests.InheritedProperties
Interface-based DTOs	IUserDto	🔲	Future

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12. Required Test Coverage (VERIFIED)

Must-Have Test Scenarios

Scenario	Category	Test File	Status
Same-name property mapping	Basic	BasicMappingGeneratorTests	✅
Different-name property mapping	Advanced	AdvancedMappingGeneratorTests	✅
Custom converter	Advanced	AdvancedMappingGeneratorTests	✅
Nested DTO mapping	Nested	NullableAndNestedGeneratorTests	✅
Collection of DTOs	Collection	CollectionMappingGeneratorTests	✅

Diagnostic Tests (Behavior Validation)

Scenario	Test	Status
Non-partial class skips generation	DiagnosticTests.NonPartialClass_SkipsGeneration	✅
Partial class generates correctly	DiagnosticTests.PartialClass_GeneratesCorrectly	✅
Unmatched property uses default	DiagnosticTests.UnmatchedProperty_GeneratesWithDefault	✅
Invalid MapProperty path	DiagnosticTests.MapProperty_WithInvalidPath_CompilesButUnmapped	✅
[GenerateProjection] without [MapFrom]	DiagnosticTests.GenerateProjection_WithoutMapFrom_SkipsProjection	✅
[MapIgnore] takes precedence	DiagnosticTests.MapIgnore_TakesPrecedence_OverMapProperty	✅
Nested DTO with [MapFrom]	DiagnosticTests.NestedDto_WithMapFrom_GeneratesCorrectly	✅
Collection with simple elements	DiagnosticTests.Collection_WithSimpleElements_MapsDirectly	✅
Struct source skips null check	DiagnosticTests.StructSource_SkipsNullCheck	✅
Class source includes null check	DiagnosticTests.ClassSource_IncludesNullCheck	✅
MapTo excludes ID by default	DiagnosticTests.MapTo_ExcludesIdByDefault	✅
Internal class generates internal extensions	DiagnosticTests.InternalClass_GeneratesInternalExtensions	✅
Empty DTO generates minimal	DiagnosticTests.EmptyDto_GeneratesMinimalMapping	✅
Multiple [MapFrom] causes error	DiagnosticTests.MultipleMapFrom_CausesDuplicateAttributeError	✅
Bidirectional mapping	DiagnosticTests.MapFrom_And_MapTo_OnSameType_GeneratesBothMethods	✅

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13. Feature Backlog

Implemented ✅

• [MapProperty(Default = "value")] per default values
• Flattening convention (Address.City → AddressCity)
• Concatenation convention (FullName → FirstName + LastName)
• EF Core projection expressions

Recently Completed ✅

• Auto-default for primitives (int? → int = GetValueOrDefault())
• Auto-default for strings (string? → string = ?? "")
• Auto-default in Projections (EF Core compatible with ?? value)
• Type conversions (ToString, Parse, enum↔string, Guid↔string)
• DateTime conversions (DateTime↔DateOnly, DateTime↔TimeOnly)
• Dictionary with DTO values (Dictionary<string, CategoryDto>)
• Inheritance mapping (base class properties mapped automatically)

Planned 🔲

• Custom projection expressions
• Async mapping per lazy loading
• Interface-based DTOs

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14. EF Core Integration

The Include Problem

When using EF Core, navigation properties require explicit Include() calls when using FromEntity():

// ⚠️ PROBLEM: Lazy loading or null navigation properties
var users = await _db.Users.ToListAsync();
var dtos = users.ToUserDto();  // Orders will be null/empty!

// ✅ SOLUTION 1: Manual Include
var users = await _db.Users
    .Include(u => u.Orders)
    .ToListAsync();
var dtos = users.ToUserDto();

// ✅ SOLUTION 2: Use Projection (BEST - optimized SQL)
var dtos = await _db.Users
    .Select(UserDto.Projection)
    .ToListAsync();

Implemented Features (Pragmatic.Mapping.EFCore)

Feature	Status	Description
SelectDto(projection)	✅	Projects query using expression
ToListDtoAsync(projection)	✅	Async projection to list
FirstOrDefaultDtoAsync(projection)	✅	Async single item projection
SingleOrDefaultDtoAsync(projection)	✅	Async single-or-default projection
ToArrayDtoAsync(projection)	✅	Async projection to array
ToPagedDtoAsync(projection, page, size)	✅	Paginated projection with metadata
ToSliceDtoAsync(projection, offset, limit)	✅	Offset/limit projection

Usage (Current)

// Projection-based (generates optimized SQL)
var dtos = await _db.Users
    .Where(u => u.IsActive)
    .ToListDtoAsync(UserDto.Projection);

// Paginated results
var page = await _db.Users
    .Where(u => u.IsActive)
    .OrderBy(u => u.Name)
    .ToPagedDtoAsync(UserDto.Projection, pageNumber: 1, pageSize: 20);
// page.Items, page.TotalCount, page.TotalPages, page.HasNextPage, etc.

Future Features (Pragmatic.Mapping.DomainEntity)

Feature	Status	Description
RequiredIncludes<TDto>()	🔲 Planned	Returns Include chain for FromEntity
WithRequiredIncludes<TDto>()	🔲 Planned	Applies required includes to query

Note: Auto-Include features require DomainEntity metadata (not yet implemented).