GN: forward_variables_from shouldn't clobber vars.

build/config/android/internal_rules.gni

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/android/config.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 import("//build/config/zip.gni")
 import("//third_party/ijar/ijar.gni")
 
 assert(is_android)
 
 rebased_android_sdk = rebase_path(android_sdk, root_build_dir)
 rebased_android_sdk_root = rebase_path(android_sdk_root, root_build_dir)
 rebased_android_sdk_build_tools =
     rebase_path(android_sdk_build_tools, root_build_dir)
 
 android_sdk_jar = "$android_sdk/android.jar"
 rebased_android_sdk_jar = rebase_path(android_sdk_jar, root_build_dir)
 android_default_aapt_path = "$rebased_android_sdk_build_tools/aapt"
 
 android_configuration_name = "Release"
 if (is_debug) {
   android_configuration_name = "Debug"
 }
 
 template("android_lint") {
   action(target_name) {
-    deps = []
     forward_variables_from(invoker,
                            [
                              "deps",
                              "data_deps",
                              "public_deps",
                              "testonly",
                            ])
+    if (!defined(deps)) {
+      deps = []
+    }
     _cache_dir = "$root_build_dir/android_lint_cache"
     _result_path = "$target_gen_dir/$target_name/result.xml"
     _config_path = "$target_gen_dir/$target_name/config.xml"
     _suppressions_file = "//build/android/lint/suppressions.xml"
     _platform_xml_path =
         "${android_sdk_root}/platform-tools/api/api-versions.xml"
 
     script = "//build/android/gyp/lint.py"
     depfile = "$target_gen_dir/$target_name.d"
     inputs = [
@@ skipping 333 matching lines @@
   action(target_name) {
     set_sources_assignment_filter([])
     type = invoker.type
     build_config = invoker.build_config
 
     assert(type == "android_apk" || type == "java_library" ||
            type == "android_resources" || type == "deps_dex" ||
            type == "android_assets" || type == "resource_rewriter" ||
            type == "java_binary" || type == "group")
 
-    deps = []
     forward_variables_from(invoker,
                            [
                              "deps",
                              "testonly",
                              "visibility",
                            ])
+    if (!defined(deps)) {
+      deps = []
+    }
 
     script = "//build/android/gyp/write_build_config.py"
     depfile = "$target_gen_dir/$target_name.d"
     inputs = []
 
     possible_deps_configs = []
     foreach(d, deps) {
       dep_gen_dir = get_label_info(d, "target_gen_dir")
       dep_name = get_label_info(d, "name")
       possible_deps_configs += [ "$dep_gen_dir/$dep_name.build_config" ]
@@ skipping 933 matching lines @@
         _jar_path,
       ]
       output = _dex_path
       deps = [ ":$_process_jar_target_name" ] + _deps + _jar_deps
     }
   }
 
   if (defined(invoker.main_class)) {
     _binary_script_target_name = "${_template_name}__java_binary_script"
     java_binary_script(_binary_script_target_name) {
-      deps = []
       forward_variables_from(invoker,
                              [
                                "bootclasspath",
                                "deps",
                                "main_class",
                                "wrapper_script_args",
                              ])
+      if (!defined(deps)) {
+        deps = []
+      }
       build_config = _build_config
       jar_path = _jar_path
       script_name = _template_name
       if (defined(invoker.wrapper_script_name)) {
         script_name = invoker.wrapper_script_name
       }
       deps += [ ":$_build_config_target_name" ]
     }
   }
 
@@ skipping 62 matching lines @@
     _supports_android = invoker.supports_android
   }
 
   _enable_errorprone = use_errorprone_java_compiler
   if (!_chromium_code) {
     _enable_errorprone = false
   } else if (defined(invoker.enable_errorprone)) {
     _enable_errorprone = invoker.enable_errorprone
   }
 
-  _enable_incremental_javac = enable_incremental_javac
-  if (defined(invoker.enable_incremental_javac)) {
-    _enable_incremental_javac = invoker.enable_incremental_javac
+  if (defined(invoker.enable_incremental_javac_override)) {
+    # Use invoker-specified override.
+    _enable_incremental_javac = invoker.enable_incremental_javac_override
+  } else {
+    # Default to build arg if not overridden.
+    _enable_incremental_javac = enable_incremental_javac
   }
 
   _manifest_entries = []
   if (defined(invoker.manifest_entries)) {
     _manifest_entries = invoker.manifest_entries
   }
 
   _srcjar_deps = []
   if (defined(invoker.srcjar_deps)) {
     _srcjar_deps += invoker.srcjar_deps
@@ skipping 156 matching lines @@
   _supports_android =
       defined(invoker.supports_android) && invoker.supports_android
   _requires_android =
       defined(invoker.requires_android) && invoker.requires_android
   assert(_requires_android || true)  # Mark as used.
   _android_manifest = "//build/android/AndroidManifest.xml"
   if (defined(invoker.android_manifest)) {
     _android_manifest = invoker.android_manifest
   }
   assert(_android_manifest != "")  # Mark as used.
-  _run_findbugs = defined(invoker.run_findbugs) && invoker.run_findbugs
+
+  if (defined(invoker.run_findbugs_override)) {
+    _run_findbugs = invoker.run_findbugs_override
+  } else {
+    _run_findbugs = run_findbugs  # Default to build arg if not overridden.
+  }
   assert(_run_findbugs || true)  # Mark as used.
 
   # Don't enable coverage, lint, findbugs unless the target has some
   # non-generated files.
   _chromium_code = defined(invoker.java_files) && invoker.java_files != []
   if (defined(invoker.chromium_code)) {
     _chromium_code = invoker.chromium_code
   }
 
   _emma_never_instrument = !_chromium_code
@@ skipping 65 matching lines @@
 
   _compile_java_target = "${_template_name}__compile_java"
   _final_deps += [ ":$_compile_java_target" ]
   compile_java(_compile_java_target) {
     forward_variables_from(invoker,
                            [
                              "alternative_android_sdk_ijar",
                              "alternative_android_sdk_ijar_dep",
                              "dist_jar_path",
                              "enable_errorprone",
-                             "enable_incremental_javac",
+                             "enable_incremental_javac_override",
                              "jar_excluded_patterns",
                              "manifest_entries",
                              "proguard_config",
                              "proguard_preprocess",
                            ])
     jar_path = _jar_path
     build_config = _build_config
     java_files = _java_files
     srcjar_deps = _srcjar_deps
     srcjars = _srcjars
@@ skipping 66 matching lines @@
         _jar_path,
       ]
       output = _dex_path
       deps = [
         ":$_compile_java_target",
       ]
     }
   }
 
   group(target_name) {
-    data_deps = []
     forward_variables_from(invoker,
                            [
                              "data_deps",
                              "visibility",
                            ])
+    if (!defined(data_deps)) {
+      data_deps = []
+    }
     public_deps = _final_deps
     if (_has_lint_target) {
       data_deps += [ ":${_template_name}__analysis" ]
     }
   }
 }
 
 # Runs process_resources.py
 template("process_resources") {
   set_sources_assignment_filter([])
@@ skipping 138 matching lines @@
 
     if (defined(invoker.args)) {
       args += invoker.args
     }
   }
 }
 
 template("copy_ex") {
   set_sources_assignment_filter([])
   action(target_name) {
-    inputs = []
-    sources = []
     forward_variables_from(invoker,
                            [
                              "data",
                              "deps",
                              "inputs",
                              "sources",
                              "testonly",
                              "visibility",
                            ])
+    if (!defined(sources)) {
+      sources = []
+    }
     script = "//build/android/gyp/copy_ex.py"
 
     depfile = "$target_gen_dir/$target_name.d"
     outputs = [
       depfile,
     ]
 
     args = [
       "--depfile",
       rebase_path(depfile, root_build_dir),
@@ skipping 116 matching lines @@
 # Generates a script in the output bin directory which runs the test
 # target using the test runner script in build/android/test_runner.py.
 template("test_runner_script") {
   testonly = true
   _test_name = invoker.test_name
   _test_type = invoker.test_type
   _incremental_install =
       defined(invoker.incremental_install) && invoker.incremental_install
 
   action(target_name) {
-    data_deps = []
-    deps = []
     forward_variables_from(invoker,
                            [
                              "data_deps",
                              "deps",
                            ])
+    if (!defined(deps)) {
+      deps = []
+    }
+    if (!defined(data_deps)) {
+      data_deps = []
+    }
 
     script = "//build/android/gyp/create_test_runner_script.py"
     depfile = "$target_gen_dir/$target_name.d"
 
     data_deps += [ "//build/android:test_runner_py" ]
     data = []
 
     test_runner_args = [
       _test_type,
       "--output-directory",
@@ skipping 112 matching lines @@
 
     args = [
       "--depfile",
       rebase_path(depfile, root_build_dir),
       "--script-output-path",
       rebase_path(generated_script, root_build_dir),
     ]
     args += test_runner_args
   }
 }