| # Copyright 2020 The Bazel Authors. All rights reserved. | 
 | # | 
 | # 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 | 
 | # | 
 | #    http://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. | 
 |  | 
 | """A rule than fails during analysis.""" | 
 |  | 
 | def _fail_rule_impl(ctx): | 
 |     if ctx.attr.header: | 
 |         fail("%s %s" % (ctx.attr.header, ctx.attr.message)) | 
 |     else: | 
 |         fail(ctx.attr.message) | 
 |  | 
 | fail_rule = rule( | 
 |     doc = "A rule that fails during analysis.", | 
 |     implementation = _fail_rule_impl, | 
 |     attrs = { | 
 |         "header": attr.string( | 
 |             doc = "Header of the message.", | 
 |         ), | 
 |         "message": attr.string( | 
 |             mandatory = True, | 
 |             doc = "Message to display.", | 
 |         ), | 
 |     }, | 
 | ) |