6 files changed, 99 insertions, 1 deletions
diff --git a/core/product_config.rbc b/core/product_config.rbc
index 8f27c998d7..eab149a8da 100644
--- a/core/product_config.rbc
+++ b/core/product_config.rbc
@@ -291,7 +291,10 @@ def _percolate_inherited(configs, cfg_name, cfg, children_names):
         child_cfg = configs[child_name][1]
         for attr, value in child_cfg.items():
             if type(value) != "list":
-                if attr in percolated_attrs or not attr in cfg:
+                # Single value variables take the first value available from the leftmost
+                # branch of the tree. If we also had "or attr in percolated_attrs" in this
+                # if statement, it would take the value from the rightmost branch.
+                if cfg.get(attr, "") == "":
                     cfg[attr] = value
                     percolated_attrs[attr] = True
                 continue
diff --git a/tests/run.rbc b/tests/run.rbc
index b82887f003..a9b16734d5 100644
--- a/tests/run.rbc
+++ b/tests/run.rbc
@@ -25,6 +25,7 @@ load(":input_variables.rbc", input_variables_init = "init")
 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")
 
 def assert_eq(expected, actual):
     if expected != actual:
@@ -129,3 +130,5 @@ assert_eq(
 (board_globals, board_config, board_globals_base) = rblf.board_configuration(board_init, board_input_vars_init)
 assert_eq({"A_LIST_VARIABLE": ["foo", "bar"]}, board_globals)
 assert_eq({"A_LIST_VARIABLE": ["foo"]}, board_globals_base)
+
+test_single_value_inheritance()
diff --git a/tests/single_value_inheritance/inherit1.rbc b/tests/single_value_inheritance/inherit1.rbc
new file mode 100644
index 0000000000..b71ffb342e
--- /dev/null
+++ b/tests/single_value_inheritance/inherit1.rbc
@@ -0,0 +1,21 @@
+# Copyright 2022 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_CHARACTERISTICS"] = "tablet"
+  cfg["PRODUCT_DEFAULT_DEV_CERTIFICATE"] = "vendor/myvendor/certs/devkeys/devkey"
diff --git a/tests/single_value_inheritance/inherit2.rbc b/tests/single_value_inheritance/inherit2.rbc
new file mode 100644
index 0000000000..be85866ffe
--- /dev/null
+++ b/tests/single_value_inheritance/inherit2.rbc
@@ -0,0 +1,20 @@
+# Copyright 2022 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_CHARACTERISTICS"] = "nosdcard"
diff --git a/tests/single_value_inheritance/product.rbc b/tests/single_value_inheritance/product.rbc
new file mode 100644
index 0000000000..332704351f
--- /dev/null
+++ b/tests/single_value_inheritance/product.rbc
@@ -0,0 +1,24 @@
+# Copyright 2022 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(":inherit1.rbc", _inherit1_init = "init")
+load(":inherit2.rbc", _inherit2_init = "init")
+
+def init(g, handle):
+  cfg = rblf.cfg(handle)
+  rblf.inherit(handle, "test/inherit1", _inherit1_init)
+  rblf.inherit(handle, "test/inherit2", _inherit2_init)
+
+  cfg["PRODUCT_DEFAULT_DEV_CERTIFICATE"] = ""
diff --git a/tests/single_value_inheritance/test.rbc b/tests/single_value_inheritance/test.rbc
new file mode 100644
index 0000000000..07a5e65cd5
--- /dev/null
+++ b/tests/single_value_inheritance/test.rbc
@@ -0,0 +1,27 @@
+# Copyright 2022 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))
+
+def test():
+    (globals, config, globals_base) = rblf.product_configuration("test/device", init, input_variables_init)
+    assert_eq("tablet", config["PRODUCT_CHARACTERISTICS"])
+    assert_eq("vendor/myvendor/certs/devkeys/devkey", config["PRODUCT_DEFAULT_DEV_CERTIFICATE"])