fix(ctx-graph-builder): set link flags to prevent ordering issues

also fixes a document builder test

Author: jaredcnance

src/JsonApiDotNetCore/Builders/ContextGraphBuilder.cs

@@ -15,13 +15,11 @@ public class ContextGraphBuilder : IContextGraphBuilder
         private bool _usesDbContext;
         public Link DocumentLinks { get; set; } = Link.All;
 
-        public ContextGraphBuilder()
-        {
-            _entities = new List<ContextEntity>();
-        }
-
         public IContextGraph Build()
         {
+            // this must be done at build so that call order doesn't matter
+            _entities.ForEach(e => e.Links = GetLinkFlags(e.EntityType));
+
             var graph = new ContextGraph()
             {
                 Entities = _entities,
@@ -41,8 +39,7 @@ public void AddResource<TResource>(string pluralizedTypeName) where TResource :
                 EntityName = pluralizedTypeName,
                 EntityType = entityType,
                 Attributes = GetAttributes(entityType),
-                Relationships = GetRelationships(entityType),
-                Links = GetLinkFlags(entityType)
+                Relationships = GetRelationships(entityType)
             });
         }
 
@@ -112,7 +109,7 @@ public void AddDbContext<T>() where T : DbContext
                     && dbSetType.GetGenericTypeDefinition() == typeof(DbSet<>))
                 {
                     var entityType = dbSetType.GetGenericArguments()[0];
-                    
+
                     VerifyEntityIsNotAlreadyDefined(entityType);
 
                     _entities.Add(new ContextEntity

src/JsonApiDotNetCore/Configuration/JsonApiOptions.cs

@@ -29,8 +29,7 @@ public void BuildContextGraph<TContext>(Action<IContextGraphBuilder> builder)
 
         public void BuildContextGraph(Action<IContextGraphBuilder> builder)
         {
-            if (builder == null)
-                throw new ArgumentException("Cannot build non-EF context graph without an IContextGraphBuilder action", nameof(builder));
+            if (builder == null) return;
 
             builder(ContextGraphBuilder);
 

test/UnitTests/Builders/DocumentBuilder_Tests.cs

@@ -80,11 +80,7 @@ public void Page_Links_Can_Be_Disabled_Globally()
             _pageManager.TotalRecords = 1;
             _pageManager.CurrentPage = 1;
 
-            _options.BuildContextGraph(builder =>
-            {
-                builder.DocumentLinks = Link.None;
-                builder.AddResource<Model>("models");
-            });
+            _options.BuildContextGraph(builder => builder.DocumentLinks = Link.None);
 
             _jsonApiContextMock
                 .Setup(m => m.ContextGraph)