Patch implementation using pure PL/pgSQL

build/build.cs

@@ -98,6 +98,12 @@ private static async Task Main(string[] args)
         Target("test-linq", DependsOn("compile-linq-tests"), () =>
             RunTests("LinqTests"));
 
+	    Target("compile-patching-tests", DependsOn("clean"), () =>
+            Run("dotnet", $"build src/PatchingTests/PatchingTests.csproj --framework {_framework} --configuration {configuration}"));
+
+        Target("test-patching", DependsOn("compile-patching-tests"), () =>
+            RunTests("PatchingTests"));
+
         Target("test-codegen", () =>
         {
             var projectPath = "src/CommandLineRunner";
@@ -118,7 +124,7 @@ private static async Task Main(string[] args)
         Target("test-plv8", DependsOn("compile", "compile-plv8"), () =>
             RunTests("Marten.PLv8.Testing"));
 
-        Target("test", DependsOn("test-base-lib", "test-core", "test-document-db", "test-event-sourcing", "test-cli", "test-linq", "test-codegen"));
+        Target("test", DependsOn("test-base-lib", "test-core", "test-document-db", "test-event-sourcing", "test-cli", "test-linq", "test-codegen", "test-patching"));
 
         Target("test-extension-libs-without-plv8", DependsOn("test-noda-time", "test-aspnetcore"));
 

src/Marten.sln

@@ -93,6 +93,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Helpdesk.Api", "samples\Hel
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Helpdesk.Api.Tests", "samples\Helpdesk\Helpdesk.Api.Tests\Helpdesk.Api.Tests.csproj", "{B0629D41-CA4E-4123-BC98-79A04D708A3E}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "PatchingTests", "PatchingTests\PatchingTests.csproj", "{EE82EFC4-FBC1-4181-9AB8-671222B60C3F}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -219,6 +221,10 @@ Global
 		{B0629D41-CA4E-4123-BC98-79A04D708A3E}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{B0629D41-CA4E-4123-BC98-79A04D708A3E}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{B0629D41-CA4E-4123-BC98-79A04D708A3E}.Release|Any CPU.Build.0 = Release|Any CPU
+		{EE82EFC4-FBC1-4181-9AB8-671222B60C3F}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{EE82EFC4-FBC1-4181-9AB8-671222B60C3F}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{EE82EFC4-FBC1-4181-9AB8-671222B60C3F}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{EE82EFC4-FBC1-4181-9AB8-671222B60C3F}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -255,5 +261,6 @@ Global
 		{F3DADE49-9C89-4F74-BCCE-7DAFD35675E9} = {79961196-DB50-4AD3-B749-D231799BCF2E}
 		{5E18DEBD-C768-4636-B167-7DA2A4954F43} = {F3DADE49-9C89-4F74-BCCE-7DAFD35675E9}
 		{B0629D41-CA4E-4123-BC98-79A04D708A3E} = {F3DADE49-9C89-4F74-BCCE-7DAFD35675E9}
+		{EE82EFC4-FBC1-4181-9AB8-671222B60C3F} = {91D87D73-EC07-4067-8A64-26A2E4F6BC83}
 	EndGlobalSection
 EndGlobal

src/Marten/Patching/IPatchExpression.cs

@@ -0,0 +1,149 @@
+using System;
+using System.Collections.Generic;
+using System.Linq.Expressions;
+
+#nullable enable
+namespace Marten.Patching;
+
+public interface IPatchExpression<T>
+{
+    /// <summary>
+    /// Set a single field or property value within the persisted JSON data
+    /// </summary>
+    /// <typeparam name="TValue"></typeparam>
+    /// <param name="name"></param>
+    /// <param name="value"></param>
+    void Set<TValue>(string name, TValue value);
+
+    /// <summary>
+    /// Set a single field or property value within the persisted JSON data
+    /// </summary>
+    /// <typeparam name="TParent"></typeparam>
+    /// <typeparam name="TValue"></typeparam>
+    /// <param name="name"></param>
+    /// <param name="expression">Path to the parent location</param>
+    /// <param name="value"></param>
+    void Set<TParent, TValue>(string name, Expression<Func<T, TParent>> expression, TValue value);
+
+    /// <summary>
+    /// Set a single field or property value within the persisted JSON data
+    /// </summary>
+    /// <typeparam name="TValue"></typeparam>
+    /// <param name="expression"></param>
+    /// <param name="value"></param>
+    void Set<TValue>(Expression<Func<T, TValue>> expression, TValue value);
+
+    /// <summary>
+    /// Copy a single field or property value within the persisted JSON data to one or more destinations
+    /// </summary>
+    /// <typeparam name="TElement"></typeparam>
+    /// <param name="expression"></param>
+    /// <param name="destinations"></param>
+    void Duplicate<TElement>(Expression<Func<T, TElement>> expression, params Expression<Func<T, TElement>>[] destinations);
+
+    /// <summary>
+    /// Increment a single field or property by adding the increment value
+    /// to the persisted value
+    /// </summary>
+    /// <param name="expression"></param>
+    /// <param name="increment"></param>
+    void Increment(Expression<Func<T, int>> expression, int increment = 1);
+
+    /// <summary>
+    /// Increment a single field or property by adding the increment value
+    /// to the persisted value
+    /// </summary>
+    /// <param name="expression"></param>
+    /// <param name="increment"></param>
+    void Increment(Expression<Func<T, long>> expression, long increment = 1);
+
+    /// <summary>
+    /// Increment a single field or property by adding the increment value
+    /// to the persisted value
+    /// </summary>
+    /// <param name="expression"></param>
+    /// <param name="increment"></param>
+    void Increment(Expression<Func<T, double>> expression, double increment = 1);
+
+    /// <summary>
+    /// Increment a single field or property by adding the increment value
+    /// to the persisted value
+    /// </summary>
+    /// <param name="expression"></param>
+    /// <param name="increment"></param>
+    void Increment(Expression<Func<T, float>> expression, float increment = 1);
+
+    /// <summary>
+    /// Append an element to the end of a child collection on the persisted
+    /// document
+    /// </summary>
+    /// <typeparam name="TElement"></typeparam>
+    /// <param name="expression"></param>
+    /// <param name="element"></param>
+    void Append<TElement>(Expression<Func<T, IEnumerable<TElement>>> expression, TElement element);
+
+    /// <summary>
+    /// Append an element to the end of a child collection on the persisted
+    /// document if the element does not already exist
+    /// </summary>
+    /// <typeparam name="TElement"></typeparam>
+    /// <param name="expression"></param>
+    /// <param name="element"></param>
+    void AppendIfNotExists<TElement>(Expression<Func<T, IEnumerable<TElement>>> expression, TElement element);
+
+    /// <summary>
+    /// Insert an element at the designated index to a child collection on the persisted document
+    /// </summary>
+    /// <typeparam name="TElement"></typeparam>
+    /// <param name="expression"></param>
+    /// <param name="element"></param>
+    /// <param name="index"></param>
+    void Insert<TElement>(Expression<Func<T, IEnumerable<TElement>>> expression, TElement element, int? index = null);
+
+    /// <summary>
+    /// Insert an element at the designated index to a child collection on the persisted document
+    /// if the value does not already exist at that index
+    /// </summary>
+    /// <typeparam name="TElement"></typeparam>
+    /// <param name="expression"></param>
+    /// <param name="element"></param>
+    /// <param name="index"></param>
+    void InsertIfNotExists<TElement>(Expression<Func<T, IEnumerable<TElement>>> expression, TElement element, int? index = null);
+
+    /// <summary>
+    /// Remove element from a child collection on the persisted document
+    /// </summary>
+    /// <typeparam name="TElement"></typeparam>
+    /// <param name="expression"></param>
+    /// <param name="element"></param>
+    /// <param name="action"></param>
+    void Remove<TElement>(Expression<Func<T, IEnumerable<TElement>>> expression, TElement element, RemoveAction action = RemoveAction.RemoveFirst);
+
+    /// <summary>
+    /// Rename a property or field in the persisted JSON document
+    /// </summary>
+    /// <param name="oldName"></param>
+    /// <param name="expression"></param>
+    void Rename(string oldName, Expression<Func<T, object>> expression);
+
+    /// <summary>
+    /// Delete a removed property or field in the persisted JSON data
+    /// </summary>
+    /// <param name="name">Redundant property or field name</param>
+    void Delete(string name);
+
+    /// <summary>
+    /// Delete a removed property or field in the persisted JSON data
+    /// </summary>
+    /// <typeparam name="TParent"></typeparam>
+    /// <param name="name">Redundant property or field name</param>
+    /// <param name="expression">Path to the parent location</param>
+    void Delete<TParent>(string name, Expression<Func<T, TParent>> expression);
+
+    /// <summary>
+    /// Delete an existing property or field in the persisted JSON data
+    /// </summary>
+    /// <typeparam name="TElement"></typeparam>
+    /// <param name="expression">Path to the property or field to delete</param>
+    void Delete<TElement>(Expression<Func<T, TElement>> expression);
+}