Merge pipeline config overlays by model ID

Reuse matching decoder and vision pipeline entries when applying config overlays, preserving filenames and existing session options. Unknown IDs continue to append in order.

Reset active parser wrappers before vector growth and add a model-free regression test covering targeted updates and new IDs.

Fixes #2004

Author: hogeheer499-commits

src/config.cpp

@@ -458,7 +458,9 @@ struct PipelineModel_Element : JSON::Element {
 
   JSON::Element& OnObject(std::string_view name) override {
     if (name == "session_options") {
-      v_.session_options = Config::SessionOptions{};
+      if (!v_.session_options) {
+        v_.session_options.emplace();
+      }
       session_options_ = std::make_unique<SessionOptions_Element>(*v_.session_options);
       return *session_options_;
     }
@@ -491,19 +493,32 @@ struct PipelineModel_Element : JSON::Element {
   StringStringMap_Element output_names_forwarder_{v_.output_names_forwarder};
 };
 
+template <typename PipelineModel>
+PipelineModel& GetOrCreatePipelineModel(std::vector<PipelineModel>& models, std::string_view model_id) {
+  auto model = std::find_if(models.begin(), models.end(),
+                            [model_id](const auto& model) { return model.model_id == model_id; });
+  if (model != models.end()) {
+    return *model;
+  }
+
+  auto& new_model = models.emplace_back();
+  new_model.model_id = model_id;
+  return new_model;
+}
+
 struct PipelineModelObject_Element : JSON::Element {
   explicit PipelineModelObject_Element(std::vector<Config::Model::Decoder::PipelineModel>& v) : v_{v} {}
 
   Element& OnObject(std::string_view name) override {
-    auto& model = v_.emplace_back();
-    model.model_id = name;
-    pipeline_model_elements_.emplace_back(model);
-    return pipeline_model_elements_.back();
+    pipeline_model_element_.reset();  // Appending below may reallocate v_.
+    auto& model = GetOrCreatePipelineModel(v_, name);
+    pipeline_model_element_ = std::make_unique<PipelineModel_Element>(model);
+    return *pipeline_model_element_;
   }
 
  private:
   std::vector<Config::Model::Decoder::PipelineModel>& v_;
-  std::vector<PipelineModel_Element> pipeline_model_elements_;
+  std::unique_ptr<PipelineModel_Element> pipeline_model_element_;
 };
 
 struct Pipeline_Element : JSON::Element {
@@ -729,7 +744,9 @@ struct VisionPipelineModel_Element : JSON::Element {
 
   Element& OnObject(std::string_view name) override {
     if (name == "session_options") {
-      v_.session_options = Config::SessionOptions{};
+      if (!v_.session_options) {
+        v_.session_options.emplace();
+      }
       session_options_ = std::make_unique<SessionOptions_Element>(*v_.session_options);
       return *session_options_;
     }
@@ -763,15 +780,15 @@ struct VisionPipelineModelObject_Element : JSON::Element {
   explicit VisionPipelineModelObject_Element(std::vector<Config::Model::Vision::PipelineModel>& v) : v_{v} {}
 
   Element& OnObject(std::string_view name) override {
-    auto& model = v_.emplace_back();
-    model.model_id = name;
-    elements_.emplace_back(model);
-    return elements_.back();
+    element_.reset();  // Appending below may reallocate v_.
+    auto& model = GetOrCreatePipelineModel(v_, name);
+    element_ = std::make_unique<VisionPipelineModel_Element>(model);
+    return *element_;
   }
 
  private:
   std::vector<Config::Model::Vision::PipelineModel>& v_;
-  std::vector<VisionPipelineModel_Element> elements_;
+  std::unique_ptr<VisionPipelineModel_Element> element_;
 };
 
 struct VisionPipeline_Element : JSON::Element {

test/config_tests.cpp

@@ -0,0 +1,103 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+#include <gtest/gtest.h>
+
+#include "filesystem.h"
+#include "config.h"
+
+namespace Generators {
+namespace {
+
+template <typename PipelineModels>
+void ExpectPipelineOverlayMerged(const PipelineModels& pipeline) {
+  ASSERT_EQ(pipeline.size(), 3U);
+
+  const auto& untouched_model = pipeline[0];
+  EXPECT_EQ(untouched_model.model_id, "untouched_model");
+  EXPECT_EQ(untouched_model.filename, "untouched.onnx");
+  ASSERT_TRUE(untouched_model.session_options);
+  ASSERT_TRUE(untouched_model.session_options->log_id);
+  EXPECT_EQ(*untouched_model.session_options->log_id, "untouched");
+  EXPECT_FALSE(untouched_model.session_options->enable_profiling);
+
+  const auto& existing_model = pipeline[1];
+  EXPECT_EQ(existing_model.model_id, "existing_model");
+  EXPECT_EQ(existing_model.filename, "existing.onnx");
+  ASSERT_TRUE(existing_model.session_options);
+  ASSERT_TRUE(existing_model.session_options->log_id);
+  EXPECT_EQ(*existing_model.session_options->log_id, "original");
+  ASSERT_TRUE(existing_model.session_options->enable_profiling);
+  EXPECT_EQ(*existing_model.session_options->enable_profiling, "profile");
+  ASSERT_EQ(existing_model.session_options->provider_options.size(), 1U);
+  EXPECT_EQ(existing_model.session_options->provider_options[0].name, "CPU");
+
+  const auto& new_model = pipeline[2];
+  EXPECT_EQ(new_model.model_id, "new_model");
+  EXPECT_EQ(new_model.filename, "new.onnx");
+}
+
+TEST(ConfigTests, PipelineOverlayMergesByModelId) {
+  Config config;
+  OverlayConfig(config, R"({
+    "model": {
+      "decoder": {
+        "pipeline": [{
+          "untouched_model": {
+            "filename": "untouched.onnx",
+            "session_options": {"log_id": "untouched"}
+          },
+          "existing_model": {
+            "filename": "existing.onnx",
+            "session_options": {
+              "log_id": "original",
+              "provider_options": [{"CPU": {}}]
+            }
+          }
+        }]
+      },
+      "vision": {
+        "pipeline": [{
+          "untouched_model": {
+            "filename": "untouched.onnx",
+            "session_options": {"log_id": "untouched"}
+          },
+          "existing_model": {
+            "filename": "existing.onnx",
+            "session_options": {
+              "log_id": "original",
+              "provider_options": [{"CPU": {}}]
+            }
+          }
+        }]
+      }
+    }
+  })");
+
+  OverlayConfig(config, R"({
+    "model": {
+      "decoder": {
+        "pipeline": [{
+          "existing_model": {
+            "session_options": {"enable_profiling": "profile"}
+          },
+          "new_model": {"filename": "new.onnx"}
+        }]
+      },
+      "vision": {
+        "pipeline": [{
+          "existing_model": {
+            "session_options": {"enable_profiling": "profile"}
+          },
+          "new_model": {"filename": "new.onnx"}
+        }]
+      }
+    }
+  })");
+
+  ExpectPipelineOverlayMerged(config.model.decoder.pipeline);
+  ExpectPipelineOverlayMerged(config.model.vision.pipeline);
+}
+
+}  // namespace
+}  // namespace Generators