don't run eagerloads on empty result set, fixes #117 (#123)

vapor · Dec 26, 2019 · 27d8b35 · 27d8b35
1 parent c232981
commit 27d8b35
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Showing 2 changed files with 28 additions and 5 deletions.
diff --git a/Sources/FluentBenchmark/FluentBenchmarker.swift b/Sources/FluentBenchmark/FluentBenchmarker.swift
@@ -50,6 +50,7 @@ public final class FluentBenchmarker {
         try self.testPerformance()
         try self.testSoftDeleteWithQuery()
         try self.testDuplicatedUniquePropertyName()
+        try self.testEmptyEagerLoadChildren()
     }
 
     public func testCreate() throws {
@@ -1757,6 +1758,23 @@ public final class FluentBenchmarker {
             //
         }
     }
+
+    // https://github.com/vapor/fluent-kit/issues/117
+    public func testEmptyEagerLoadChildren() throws {
+        try runTest(#function, [
+            GalaxyMigration(),
+            PlanetMigration(),
+            GalaxySeed(),
+            PlanetSeed()
+        ]) {
+            let galaxies = try Galaxy.query(on: self.database)
+                .filter(\.$name == "foo")
+                .with(\.$planets)
+                .all().wait()
+
+            XCTAssertEqual(galaxies.count, 0)
+        }
+    }
 
     // MARK: Utilities
 

diff --git a/Sources/FluentKit/Query/QueryBuilder.swift b/Sources/FluentKit/Query/QueryBuilder.swift
@@ -641,12 +641,17 @@ public final class QueryBuilder<Model>
         // if eager loads exist, run them, and update models
         if !self.eagerLoads.requests.isEmpty {
             return done.flatMap {
-                return .andAllSucceed(self.eagerLoads.requests.values.map { eagerLoad in
+                // don't run eager loads if result set was empty
+                guard !all.isEmpty else {
+                    return self.database.eventLoop.makeSucceededFuture(())
+                }
+                // run eager loads
+                return EventLoopFuture<Void>.andAllSucceed(self.eagerLoads.requests.values.map { eagerLoad in
                     return eagerLoad.run(models: all, on: self.database)
-                }, on: self.database.eventLoop)
-            }.flatMapThrowing {
-                try all.forEach { model in
-                    try model.eagerLoad(from: self.eagerLoads)
+                }, on: self.database.eventLoop).flatMapThrowing {
+                    try all.forEach { model in
+                        try model.eagerLoad(from: self.eagerLoads)
+                    }
                 }
             }
         } else {