|  | # 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.", | 
|  | ), | 
|  | }, | 
|  | ) |