Runtime reporting of the conversion errors.

Bug: 204062171
Test: rbcrun build/make/tests/conversion_error.rbc (displays a message, stops)
  rbcrun RBC_MK2RBC_CONTINUE=t build/make/tests/conversion_error.rbc  (displays a message and continues)
Change-Id: Idf0fe6bbb08b1eca1f392d81950eed4a214f3289

core/product_config.rbc

@@ -549,6 +549,18 @@ def _mkwarning(file, message = ""):
     """Prints warning."""
     rblf_log(file, "warning", message, sep = ':')
 
+def _mk2rbc_error(loc, message):
+    """Prints a message about conversion error and stops.
+
+    If RBC_MK2RBC_CONTINUE environment variable is set,
+    the execution will continue after the message is printed.
+    """
+    if _options.mk2rbc_continue:
+        rblf_log(loc, message, sep = ':')
+    else:
+        _mkerror(loc, message)
+
+
 def _mkinfo(file, message = ""):
     """Prints info."""
     rblf_log(message)
@@ -659,6 +671,7 @@ def __get_options():
         rearrange = "",
         trace_modules = False,
         trace_variables = [],
+        mk2rbc_continue = False,
     )
     for x in getattr(rblf_cli, "RBC_OUT", "").split(","):
         if x == "sort" or x == "unique":
@@ -676,6 +689,8 @@ def __get_options():
             settings["trace_modules"] = True
         elif x != "":
             settings["trace_variables"].append(x)
+    if getattr(rblf_cli, "RBC_MK2RBC_CONTINUE", ""):
+        settings["mk2rbc_continue"] = True
     return struct(**settings)
 
 # Settings used during debugging.
@@ -703,6 +718,7 @@ rblf = struct(
     init_globals = _init_globals,
     inherit = _inherit,
     indirect = _indirect,
+    mk2rbc_error = _mk2rbc_error,
     mkdist_for_goals = _mkdist_for_goals,
     mkinfo = _mkinfo,
     mkerror = _mkerror,

tests/conversion_error.rbc

@@ -0,0 +1,27 @@
+# Copyright 2021 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.
+
+
+# Run test configuration and verify its result.
+# The main configuration file is device.rbc.
+# It inherits part1.rbc and also includes include1.rbc
+# TODO(asmundak): more tests are needed to verify that:
+#  * multi-level inheritance works as expected
+#  * all runtime functions (wildcard, regex, etc.) work
+
+load("//build/make/core:product_config.rbc", "rblf")
+load(":version_defaults.rbc", "version_defaults")
+load(":device.rbc", "init")
+
+rblf.mk2rbc_error("file.mk:123", "cannot convert")