test_suite cycles crash Bazel

[benjaminp]

$ bazel version
Build label: 
Build target: bazel-out/k8-opt/bin/src/main/java/com/google/devtools/build/lib/bazel/BazelServer_deploy.jar
Build time: Thu Aug 9 18:23:10 2018 (1533838990)
Build timestamp: 1533838990
Build timestamp as int: 1533838990
$ touch WORKSPACE
$ cat > BUILD 
test_suite(name = 'a', tests = [':b'])
test_suite(name = 'b', tests = [':a'])
$ bazel build //:a
Unhandled exception thrown during build; message: topLevelKey: [//:a] EXPAND_TEST_SUITES com.google.devtools.build.lib.pkgcache.TestFilter@e17a1
alreadyReported: false
path to cycle:
[//:a] EXPAND_TEST_SUITES com.google.devtools.build.lib.pkgcache.TestFilter@e17a1
ExpandTestSuites([//:a])
cycle:
TestsInSuite(//:a, strict=true)
TestsInSuite(//:b, strict=true)

INFO: Elapsed time: 0.398s
INFO: 0 processes.
FAILED: Build did NOT complete successfully (1 packages loaded)
java.lang.IllegalStateException: topLevelKey: [//:a] EXPAND_TEST_SUITES com.google.devtools.build.lib.pkgcache.TestFilter@e17a1
alreadyReported: false
path to cycle:
[//:a] EXPAND_TEST_SUITES com.google.devtools.build.lib.pkgcache.TestFilter@e17a1
ExpandTestSuites([//:a])
cycle:
TestsInSuite(//:a, strict=true)
TestsInSuite(//:b, strict=true)

	at com.google.common.base.Preconditions.checkState(Preconditions.java:507)
	at com.google.devtools.build.skyframe.CyclesReporter.reportCycles(CyclesReporter.java:85)
	at com.google.devtools.build.lib.skyframe.SkyframeExecutor.loadTargetPatterns(SkyframeExecutor.java:2240)
	at com.google.devtools.build.lib.buildtool.AnalysisPhaseRunner.evaluateTargetPatterns(AnalysisPhaseRunner.java:170)
	at com.google.devtools.build.lib.buildtool.AnalysisPhaseRunner.execute(AnalysisPhaseRunner.java:85)
	at com.google.devtools.build.lib.buildtool.BuildTool.buildTargets(BuildTool.java:143)
	at com.google.devtools.build.lib.buildtool.BuildTool.processRequest(BuildTool.java:262)
	at com.google.devtools.build.lib.runtime.commands.BuildCommand.exec(BuildCommand.java:83)
	at com.google.devtools.build.lib.runtime.BlazeCommandDispatcher.execExclusively(BlazeCommandDispatcher.java:484)
	at com.google.devtools.build.lib.runtime.BlazeCommandDispatcher.exec(BlazeCommandDispatcher.java:204)
	at com.google.devtools.build.lib.server.GrpcServerImpl.executeCommand(GrpcServerImpl.java:870)
	at com.google.devtools.build.lib.server.GrpcServerImpl.access$2100(GrpcServerImpl.java:111)
	at com.google.devtools.build.lib.server.GrpcServerImpl$2.lambda$run$0(GrpcServerImpl.java:939)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
java.lang.IllegalStateException: topLevelKey: [//:a] EXPAND_TEST_SUITES com.google.devtools.build.lib.pkgcache.TestFilter@e17a1
alreadyReported: false
path to cycle:
[//:a] EXPAND_TEST_SUITES com.google.devtools.build.lib.pkgcache.TestFilter@e17a1
ExpandTestSuites([//:a])
cycle:
TestsInSuite(//:a, strict=true)
TestsInSuite(//:b, strict=true)

	at com.google.common.base.Preconditions.checkState(Preconditions.java:507)
	at com.google.devtools.build.skyframe.CyclesReporter.reportCycles(CyclesReporter.java:85)
	at com.google.devtools.build.lib.skyframe.SkyframeExecutor.loadTargetPatterns(SkyframeExecutor.java:2240)
	at com.google.devtools.build.lib.buildtool.AnalysisPhaseRunner.evaluateTargetPatterns(AnalysisPhaseRunner.java:170)
	at com.google.devtools.build.lib.buildtool.AnalysisPhaseRunner.execute(AnalysisPhaseRunner.java:85)
	at com.google.devtools.build.lib.buildtool.BuildTool.buildTargets(BuildTool.java:143)
	at com.google.devtools.build.lib.buildtool.BuildTool.processRequest(BuildTool.java:262)
	at com.google.devtools.build.lib.runtime.commands.BuildCommand.exec(BuildCommand.java:83)
	at com.google.devtools.build.lib.runtime.BlazeCommandDispatcher.execExclusively(BlazeCommandDispatcher.java:484)
	at com.google.devtools.build.lib.runtime.BlazeCommandDispatcher.exec(BlazeCommandDispatcher.java:204)
	at com.google.devtools.build.lib.server.GrpcServerImpl.executeCommand(GrpcServerImpl.java:870)
	at com.google.devtools.build.lib.server.GrpcServerImpl.access$2100(GrpcServerImpl.java:111)
	at com.google.devtools.build.lib.server.GrpcServerImpl$2.lambda$run$0(GrpcServerImpl.java:939)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
FAILED: Build did NOT complete successfully (1 packages loaded)