Enable using the attached model during pivot editing (#565)

* Make sure the value of the right-hand side of a new pivot is set to the model that particular pivot refers to so the edit closure can pull details from it without having to match up IDs by hand. Add a test for it. While we're at it, add a sample of an extra pivot property to PlanetTag and clean up its migration.

.api-breakage/allowlist-branch-make-pivot-rhs-available-during-array-attach.txt

@@ -0,0 +1 @@
+API breakage: constructor PlanetTag.init(id:planetID:tagID:) has been removed

.github/workflows/test.yml

@@ -7,7 +7,7 @@ on:
   push: { branches: [ main ] }
 
 env:
-  LOG_LEVEL: debug
+  LOG_LEVEL: info
   SWIFT_DETERMINISTIC_HASHING: 1
   POSTGRES_HOSTNAME: 'psql-a'
   POSTGRES_HOSTNAME_A: 'psql-a'

Sources/FluentBenchmark/SolarSystem/PlanetTag.swift

@@ -14,29 +14,36 @@ public final class PlanetTag: Model {
 
     @Parent(key: "tag_id")
     public var tag: Tag
+
+    @OptionalField(key: "comments")
+    public var comments: String?
 
     public init() { }
 
-    public init(id: IDValue? = nil, planetID: Planet.IDValue, tagID: Tag.IDValue) {
+    public init(id: IDValue? = nil, planetID: Planet.IDValue, tagID: Tag.IDValue, comments: String? = nil) {
         self.id = id
         self.$planet.id = planetID
         self.$tag.id = tagID
+        self.comments = comments
     }
 }
 
 public struct PlanetTagMigration: Migration {
     public init() { }
 
     public func prepare(on database: Database) -> EventLoopFuture<Void> {
-        database.schema("planet+tag")
-            .field("id", .uuid, .identifier(auto: false))
-            .field("planet_id", .uuid, .required, .references("planets", "id"))
-            .field("tag_id", .uuid, .required, .references("tags", "id"))
+        database.schema(PlanetTag.schema)
+            .id()
+            .field("planet_id", .uuid, .required)
+            .field("tag_id", .uuid, .required)
+            .field("comments", .string)
+            .foreignKey("planet_id", references: Planet.schema, .id)
+            .foreignKey("tag_id", references: Tag.schema, .id)
             .create()
     }
 
     public func revert(on database: Database) -> EventLoopFuture<Void> {
-        database.schema("planet+tag").delete()
+        database.schema(PlanetTag.schema).delete()
     }
 }
 

Sources/FluentBenchmark/Tests/SiblingsTests.swift

@@ -62,6 +62,23 @@ extension FluentBenchmarker {
                 XCTAssertEqual(tags.count, 2)
                 XCTAssertEqual(tags.map(\.name).sorted(), ["Inhabited", "Small Rocky"])
             }
+
+            try earth.$tags.detachAll(on: self.database).wait()
+
+            // check pivot provided to the edit closure has the "to" model when attaching
+            try earth.$tags.attach([inhabited, smallRocky], on: self.database) { pivot in
+                guard pivot.$tag.value != nil else {
+                    return XCTFail("planet tag pivot should have tag available during editing")
+                }
+                pivot.comments = "Tagged with name \(pivot.tag.name)"
+            }.wait()
+
+            do {
+                let pivots = try earth.$tags.$pivots.get(reload: true, on: self.database).wait()
+
+                XCTAssertEqual(pivots.count, 2)
+                XCTAssertEqual(pivots.compactMap(\.comments).sorted(), ["Tagged with name Inhabited", "Tagged with name Small Rocky"])
+            }
         }
     }
 

Sources/FluentKit/Properties/Siblings.swift

@@ -127,6 +127,7 @@ public final class SiblingsProperty<From, To, Through>
             let pivot = Through()
             pivot[keyPath: self.from].id = fromID
             pivot[keyPath: self.to].id = toID
+            pivot[keyPath: self.to].value = to
             edit(pivot)
             return pivot
         }.create(on: database)
@@ -180,6 +181,7 @@ public final class SiblingsProperty<From, To, Through>
         let pivot = Through()
         pivot[keyPath: self.from].id = fromID
         pivot[keyPath: self.to].id = toID
+        pivot[keyPath: self.to].value = to
         edit(pivot)
         return pivot.save(on: database)
     }