"Steal" single value variables in rbc inheritance

This behavior of "stealing" values from parent makefiles is needed to
match make. We already had similar behavior for list variables via
the __move_items function, but were missing it for single value
variables.

Test: ./out/rbcrun -mode rbc ./build/make/tests/run.rbc
Change-Id: Ib320b9b1cce0224184f585c7a391be1b5353b440

core/product_config.rbc

@@ -351,6 +351,7 @@ def _percolate_inherited(configs, cfg_name, cfg, children_names):
                 if cfg.get(attr, "") == "":
                     cfg[attr] = value
                     percolated_attrs[attr] = True
+                    child_cfg.pop(attr)
 
     for attr in _options.trace_variables:
         if attr in percolated_attrs:
@@ -360,7 +361,7 @@ def __move_items(to_list, from_cfg, attr):
     value = from_cfg.get(attr, [])
     if value:
         to_list.extend(value)
-        from_cfg[attr] = []
+        from_cfg.pop(attr)
 
 def _indirect(pcm_name):
     """Returns configuration item for the inherited module."""

tests/run.rbc

@@ -26,6 +26,7 @@ load(":product.rbc", "init")
 load(":board.rbc", board_init = "init")
 load(":board_input_vars.rbc", board_input_vars_init = "init")
 load("//build/make/tests/single_value_inheritance:test.rbc", test_single_value_inheritance = "test")
+load("//build/make/tests/single_value_inheritance_2:test.rbc", test_single_value_inheritance_2 = "test")
 load("//build/make/tests/artifact_path_requirements:test.rbc", test_artifact_path_requirements = "test")
 load("//build/make/tests/prefixed_sort_order:test.rbc", test_prefixed_sort_order = "test")
 load("//build/make/tests/inherits_in_regular_variables:test.rbc", test_inherits_in_regular_variables = "test")
@@ -181,6 +182,7 @@ assert_eq("f", cfg["BAZ"])
 assert_eq("", g.get("NEWVAR"))
 
 test_single_value_inheritance()
+test_single_value_inheritance_2()
 test_artifact_path_requirements()
 test_prefixed_sort_order()
 test_inherits_in_regular_variables()

tests/single_value_inheritance_2/a.rbc

@@ -0,0 +1,20 @@
+# Copyright 2024 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+load("//build/make/core:product_config.rbc", "rblf")
+
+def init(g, handle):
+  cfg = rblf.cfg(handle)
+
+  cfg["PRODUCT_ENABLE_UFFD_GC"] = "true"

tests/single_value_inheritance_2/b.rbc

@@ -0,0 +1,20 @@
+# Copyright 2024 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+load("//build/make/core:product_config.rbc", "rblf")
+
+def init(g, handle):
+  cfg = rblf.cfg(handle)
+
+  cfg["PRODUCT_ENABLE_UFFD_GC"] = "default"

tests/single_value_inheritance_2/c.rbc

@@ -0,0 +1,21 @@
+# Copyright 2024 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+load("//build/make/core:product_config.rbc", "rblf")
+load(":b.rbc", _b_init = "init")
+
+def init(g, handle):
+  cfg = rblf.cfg(handle)
+
+  rblf.inherit(handle, "test/b", _b_init)

tests/single_value_inheritance_2/d.rbc

@@ -0,0 +1,23 @@
+# Copyright 2024 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+load("//build/make/core:product_config.rbc", "rblf")
+load(":c.rbc", _c_init = "init")
+load(":a.rbc", _a_init = "init")
+
+def init(g, handle):
+  cfg = rblf.cfg(handle)
+
+  rblf.inherit(handle, "test/a", _a_init)
+  rblf.inherit(handle, "test/c", _c_init)

tests/single_value_inheritance_2/product.rbc

@@ -0,0 +1,23 @@
+# Copyright 2024 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+load("//build/make/core:product_config.rbc", "rblf")
+load(":b.rbc", _b_init = "init")
+load(":d.rbc", _d_init = "init")
+
+def init(g, handle):
+  cfg = rblf.cfg(handle)
+
+  rblf.inherit(handle, "test/b", _b_init)
+  rblf.inherit(handle, "test/d", _d_init)

tests/single_value_inheritance_2/test.rbc

@@ -0,0 +1,40 @@
+# Copyright 2024 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+load("//build/make/core:product_config.rbc", "rblf")
+load("//build/make/tests/input_variables.rbc", input_variables_init = "init")
+load(":product.rbc", "init")
+
+
+def assert_eq(expected, actual):
+    if expected != actual:
+        fail("Expected '%s', got '%s'" % (expected, actual))
+
+# This test is testing that single value variables are "stolen" when processing the inheritance
+# graph. i.e. if you have a graph like this:
+#
+#   B   A
+#   |\  |
+#   | C |
+#    \ \|
+#     \ D
+#      \|
+#       E
+#
+# The same variable is defined in both A and B. In D, the value from A is chosen because it comes
+# alphabetically before C. But then in E, the value from D is chosen instead of the value from B,
+# because the value of B was "stolen" and sucked into C, leaving B with no value set.
+def test():
+    (globals, globals_base) = rblf.product_configuration("test/device", init, input_variables_init)
+    assert_eq("true", globals["PRODUCTS.test/device.mk.PRODUCT_ENABLE_UFFD_GC"])