Keep the with loader save order the same as with schema overload, with ITransformer always first.

Author: TomFinley

src/Microsoft.ML.Data/Model/ModelOperationsCatalog.cs

@@ -39,12 +39,12 @@ private static TransformerChain<ITransformer> CreateChain(ITransformer transform
         /// <summary>
         /// Save a transformer model and the loader used to create its input data to the stream.
         /// </summary>
-        /// <param name="loader">The loader that was used to create data to train the model.</param>
         /// <param name="model">The trained model to be saved. Note that this can be <see langword="null"/>, as a shorthand
         /// for an empty data set. Upon loading with <see cref="LoadWithDataLoader(Stream, out IDataLoader{IMultiStreamSource})"/>
         /// the returned valued will be an empty <see cref="TransformerChain{TLastTransformer}"/>.</param>
+        /// <param name="loader">The loader that was used to create data to train the model.</param>
         /// <param name="stream">A writeable, seekable stream to save to.</param>
-        public void Save<TSource>(IDataLoader<TSource> loader, ITransformer model, Stream stream)
+        public void Save<TSource>(ITransformer model, IDataLoader<TSource> loader, Stream stream)
         {
             _env.CheckValue(loader, nameof(loader));
             _env.CheckValueOrNull(model);
@@ -65,19 +65,19 @@ public void Save<TSource>(IDataLoader<TSource> loader, ITransformer model, Strea
         /// <summary>
         /// Save a transformer model and the loader used to create its input data to the file.
         /// </summary>
-        /// <param name="loader">The loader that was used to create data to train the model.</param>
         /// <param name="model">The trained model to be saved. Note that this can be <see langword="null"/>, as a shorthand
         /// for an empty data set. Upon loading with <see cref="LoadWithDataLoader(Stream, out IDataLoader{IMultiStreamSource})"/>
         /// the returned valued will be an empty <see cref="TransformerChain{TLastTransformer}"/>.</param>
+        /// <param name="loader">The loader that was used to create data to train the model.</param>
         /// <param name="filePath">Path where model should be saved.</param>
-        public void Save<TSource>(IDataLoader<TSource> loader, ITransformer model, string filePath)
+        public void Save<TSource>(ITransformer model, IDataLoader<TSource> loader, string filePath)
         {
-            _env.CheckValue(loader, nameof(loader));
             _env.CheckValueOrNull(model);
+            _env.CheckValue(loader, nameof(loader));
             _env.CheckNonEmpty(filePath, nameof(filePath));
 
             using (var stream = File.Create(filePath))
-                Save(loader, model, stream);
+                Save(model, loader, stream);
         }
 
         /// <summary>

test/Microsoft.ML.Functional.Tests/ModelLoading.cs

@@ -66,11 +66,11 @@ public void LoadModelAndExtractPredictor()
             // In this case we have combined the loader with the transformer model to form a "composite" loader, and are just
             // saving that one loader to this file.
             string compositeLoaderModelPath = GetOutputPath(FullTestName + "-composite-model.zip");
-            _ml.Model.Save(compositeLoaderModel, null, compositeLoaderModelPath);
+            _ml.Model.Save(null, compositeLoaderModel, compositeLoaderModelPath);
 
             // In this case we are saving the transformer model, as well as the associated data loader.
             string loaderAndTransformerModelPath = GetOutputPath(FullTestName + "-loader-transformer.zip");
-            _ml.Model.Save(loader, transformerModel, loaderAndTransformerModelPath);
+            _ml.Model.Save(transformerModel, loader, loaderAndTransformerModelPath);
 
             ITransformer loadedTransformerModel;
             IDataLoader<IMultiStreamSource> loadedCompositeLoader;
@@ -141,7 +141,7 @@ public void SaveAndLoadModelWithLoader()
 
             // Save and reload.
             string modelPath = GetOutputPath(FullTestName + "-model.zip");
-            _ml.Model.Save(loader, model, modelPath);
+            _ml.Model.Save(model, loader, modelPath);
 
             IDataLoader<IMultiStreamSource> loadedLoader;
             ITransformer loadedModelWithoutLoader;
@@ -196,7 +196,7 @@ public void LoadSchemaAndCreateNewData()
 
             // Save and reload.
             string modelPath = GetOutputPath(FullTestName + "-model.zip");
-            _ml.Model.Save(loader, model, modelPath);
+            _ml.Model.Save(model, loader, modelPath);
 
             ITransformer loadedModel;
             DataViewSchema loadedSchema;
@@ -219,7 +219,7 @@ public void SaveTextLoaderAndLoad()
             var loader = _ml.Data.CreateTextLoader<InputData>(hasHeader: true, dataSample: file);
 
             string modelPath = GetOutputPath(FullTestName + "-model.zip");
-            _ml.Model.Save(loader, null, modelPath);
+            _ml.Model.Save(null, loader, modelPath);
 
             Load(modelPath, out var loadedWithSchema, out var loadedSchema,
                 out var loadedWithLoader, out var loadedLoaderWithTransformer);
@@ -248,7 +248,7 @@ public void SaveCompositeLoaderAndLoad()
             var model = composite.Fit(file);
 
             string modelPath = GetOutputPath(FullTestName + "-model.zip");
-            _ml.Model.Save(model, null, modelPath);
+            _ml.Model.Save(null, model, modelPath);
 
             Load(modelPath, out var loadedWithSchema, out var loadedSchema,
                 out var loadedWithLoader, out var loadedLoaderWithTransformer);
@@ -294,7 +294,7 @@ public void SaveLoaderAndTransformerAndLoad()
             Assert.True(expectedInputSchema["Features"].HasSlotNames());
 
             string modelPath = GetOutputPath(FullTestName + "-model.zip");
-            _ml.Model.Save(loader, model, modelPath);
+            _ml.Model.Save(model, loader, modelPath);
 
             // Reload the loader and schema.
             Load(modelPath, out var loadedWithSchema, out var loadedInputSchema,