Support for excluding variable from forwarding via forward_variables_form.

tools/gn/function_forward_variables_from_unittest.cc

Index: tools/gn/function_forward_variables_from_unittest.cc
diff --git a/tools/gn/function_forward_variables_from_unittest.cc b/tools/gn/function_forward_variables_from_unittest.cc
index c3dd715f4f1a8dc11585ddbe8fc08bcfcdeac791..e5137a48b266cc8c5bd161caca2ab51b2f9cb5d3 100644
--- a/tools/gn/function_forward_variables_from_unittest.cc
+++ b/tools/gn/function_forward_variables_from_unittest.cc
@@ -32,6 +32,34 @@ TEST(FunctionForwardVariablesFrom, List) {
   setup.print_output().clear();
 }
 
+TEST(FunctionForwardVariablesFrom, ListWithExclusion) {
+  Scheduler scheduler;
+  TestWithScope setup;
+
+  // Defines a template and copy the two x and y, and z values out.
+  TestParseInput input(
+    "template(\"a\") {\n"
+    "  forward_variables_from(invoker, [\"x\", \"y\", \"z\"], [\"z\"])\n"
+    "  assert(!defined(z))\n"  // "z" should still be undefined.
+    "  print(\"$target_name, $x, $y\")\n"
+    "}\n"
+    "a(\"target\") {\n"
+    "  x = 1\n"
+    "  y = 2\n"
+    "  z = 3\n"
+    "  print(\"$z\")\n"
+    "}\n");
+
+  ASSERT_FALSE(input.has_error());
+
+  Err err;
+  input.parsed()->Execute(setup.scope(), &err);
+  ASSERT_FALSE(err.has_error()) << err.message();
+
+  EXPECT_EQ("3\ntarget, 1, 2\n", setup.print_output());
+  setup.print_output().clear();
+}
+
 TEST(FunctionForwardVariablesFrom, ErrorCases) {
   Scheduler scheduler;
   TestWithScope setup;
@@ -65,19 +93,61 @@ TEST(FunctionForwardVariablesFrom, ErrorCases) {
   EXPECT_TRUE(err.has_error());
   EXPECT_EQ("Not a valid list of variables to copy.", err.message());
 
+  // Type check the exclusion list.
+  TestParseInput invalid_exclusion_list(
+    "template(\"c\") {\n"
+    "  forward_variables_from(invoker, \"*\", 42)\n"
+    "  print(\"$target_name\")\n"
+    "}\n"
+    "c(\"target\") {\n"
+    "}\n");
+  ASSERT_FALSE(invalid_exclusion_list.has_error());
+  err = Err();
+  invalid_exclusion_list.parsed()->Execute(setup.scope(), &err);
+  EXPECT_TRUE(err.has_error());
+  EXPECT_EQ("Not a valid list of variables to exclude.", err.message());
+
   // Programmatic values should error.
   TestParseInput prog(
-    "template(\"c\") {\n"
+    "template(\"d\") {\n"
     "  forward_variables_from(invoker, [\"root_out_dir\"])\n"
     "  print(\"$target_name\")\n"
     "}\n"
-    "c(\"target\") {\n"
+    "d(\"target\") {\n"
     "}\n");
   ASSERT_FALSE(prog.has_error());
   err = Err();
   prog.parsed()->Execute(setup.scope(), &err);
   EXPECT_TRUE(err.has_error());
   EXPECT_EQ("This value can't be forwarded.", err.message());
+
+  // Not enough arguments.
+  TestParseInput not_enough_arguments(
+    "template(\"e\") {\n"
+    "  forward_variables_from(invoker)\n"
+    "  print(\"$target_name\")\n"
+    "}\n"
+    "e(\"target\") {\n"
+    "}\n");
+  ASSERT_FALSE(not_enough_arguments.has_error());
+  err = Err();
+  not_enough_arguments.parsed()->Execute(setup.scope(), &err);
+  EXPECT_TRUE(err.has_error());
+  EXPECT_EQ("Wrong number of arguments.", err.message());
+
+  // Too many arguments.
+  TestParseInput too_many_arguments(
+    "template(\"f\") {\n"
+    "  forward_variables_from(invoker, \"*\", [], [])\n"
+    "  print(\"$target_name\")\n"
+    "}\n"
+    "f(\"target\") {\n"
+    "}\n");
+  ASSERT_FALSE(too_many_arguments.has_error());
+  err = Err();
+  too_many_arguments.parsed()->Execute(setup.scope(), &err);
+  EXPECT_TRUE(err.has_error());
+  EXPECT_EQ("Wrong number of arguments.", err.message());
 }
 
 TEST(FunctionForwardVariablesFrom, Star) {
@@ -106,3 +176,33 @@ TEST(FunctionForwardVariablesFrom, Star) {
   EXPECT_EQ("target, 1, 2\n", setup.print_output());
   setup.print_output().clear();
 }
+
+
+TEST(FunctionForwardVariablesFrom, StarWithExclusion) {
+  Scheduler scheduler;
+  TestWithScope setup;
+
+  // Defines a template and copy all values except z value. The "*" behavior
+  // should clobber existing variables with the same name.
+  TestParseInput input(
+    "template(\"a\") {\n"
+    "  x = 1000000\n"  // Should be clobbered.
+    "  forward_variables_from(invoker, \"*\", [\"z\"])\n"
+    "  print(\"$target_name, $x, $y\")\n"
+    "}\n"
+    "a(\"target\") {\n"
+    "  x = 1\n"
+    "  y = 2\n"
+    "  z = 3\n"
+    "  print(\"$z\")\n"
+    "}\n");
+
+  ASSERT_FALSE(input.has_error());
+
+  Err err;
+  input.parsed()->Execute(setup.scope(), &err);
+  ASSERT_FALSE(err.has_error()) << err.message();
+
+  EXPECT_EQ("3\ntarget, 1, 2\n", setup.print_output());
+  setup.print_output().clear();
+}