Treat Objective-C static analysis warnings as errors (#16293)

- Update Objective-C static analysis check to fail on warnings.
- Address warning.
- Clean up build definition.

objectivec/include/ort_env.h

@@ -16,7 +16,7 @@ extern "C" {
  *
  * Available since 1.15.
  */
-NSString* ORTVersion(void);
+NSString* _Nullable ORTVersion(void);
 
 #ifdef __cplusplus
 }

objectivec/ort_env.mm

@@ -12,9 +12,8 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
-NSString* ORTVersion(void) {
-  std::string result = OrtGetApiBase()->GetVersionString();
-  return [NSString stringWithUTF8String:result.c_str()];
+NSString* _Nullable ORTVersion(void) {
+  return [NSString stringWithUTF8String:OrtGetApiBase()->GetVersionString()];
 }
 
 @implementation ORTEnv {

tools/ci_build/build.py

@@ -542,11 +542,12 @@ def parse_arguments():
     parser.add_argument(
         "--cmake_generator",
         choices=[
+            "MinGW Makefiles",
+            "Ninja",
+            "NMake Makefiles",
+            "Unix Makefiles",
             "Visual Studio 16 2019",
             "Visual Studio 17 2022",
-            "Ninja",
-            "MinGW Makefiles",
-            "NMake Makefiles",
             "Xcode",
         ],
         default=None,

tools/ci_build/github/apple/objectivec/static_analysis/requirements.txt

@@ -1 +0,0 @@
-ninja==1.10.2

tools/ci_build/github/azure-pipelines/mac-objc-static-analysis-ci-pipeline.yml

@@ -17,14 +17,10 @@ jobs:
       addToPath: true
       architecture: "x64"
 
-  - script: |
-      pip install -r tools/ci_build/github/apple/objectivec/static_analysis/requirements.txt
-    displayName: Install tools
-
   - script: |
       python tools/ci_build/build.py \
         --build_dir "$(Build.BinariesDirectory)" \
-        --cmake_generator "Ninja" \
+        --cmake_generator "Unix Makefiles" \
         --config Debug \
         --build_shared_lib --use_coreml --build_objc \
         --cmake_extra_defines CMAKE_EXPORT_COMPILE_COMMANDS=ON \
@@ -33,9 +29,14 @@ jobs:
     displayName: Generate compile_commands.json and ONNX protobuf files
 
   - script: |
+      set -e
+
+      CLANG_TIDY_CHECKS="-*,clang-analyzer-*"
+
       "$(brew --prefix llvm@15)/bin/clang-tidy" \
         -p="$(Build.BinariesDirectory)/Debug" \
-        --checks="-*,clang-analyzer-*" \
+        --checks="${CLANG_TIDY_CHECKS}" \
+        --warnings-as-errors="${CLANG_TIDY_CHECKS}" \
         --header-filter="objectivec/include|objectivec|onnxruntime/core" \
         ./objectivec/*.mm \
         ./onnxruntime/core/platform/apple/logging/apple_log_sink.mm \