panic: fatal: An assertion has failed goroutine 159 [running]: github.com/pulumi/pulumi/pkg/util/contract.failfast(0xef018d, 0x17) /home/travis/gopath/src/github.com/pulumi/pulumi/pkg/util/contract/failfast.go:23 +0xf3 github.com/pulumi/pulumi/pkg/util/contract.Assert(0x0) /home/travis/gopath/src/github.com/pulumi/pulumi/pkg/util/contract/assert.go:26 +0x49 github.com/pulumi/pulumi/pkg/resource/plugin.(*provider).Read(0xc420946ff0, 0xc42147d170, 0x81, 0x0, 0x0, 0xc42113b770, 0xc420946ff0, 0x1, 0x42ebab, 0xc4210ebed4) /home/travis/gopath/src/github.com/pulumi/pulumi/pkg/resource/plugin/provider_plugin.go:401 +0x5e github.com/pulumi/pulumi/pkg/resource/deploy.(*refreshSourceIterator).newRefreshGoal(0xc42101ca20, 0xc4200e2000, 0x3f, 0x0, 0x0) /home/travis/gopath/src/github.com/pulumi/pulumi/pkg/resource/deploy/source_refresh.go:158 +0x515 github.com/pulumi/pulumi/pkg/resource/deploy.(*refreshSourceIterator).Next(0xc42101ca20, 0x0, 0x0, 0x0, 0x0) /home/travis/gopath/src/github.com/pulumi/pulumi/pkg/resource/deploy/source_refresh.go:129 +0xe6 github.com/pulumi/pulumi/pkg/resource/deploy.(*PlanExecutor).Execute.func2(0xc42028ae10, 0xc421032180) /home/travis/gopath/src/github.com/pulumi/pulumi/pkg/resource/deploy/plan_executor.go:96 +0x4b created by github.com/pulumi/pulumi/pkg/resource/deploy.(*PlanExecutor).Execute /home/travis/gopath/src/github.com/pulumi/pulumi/pkg/resource/deploy/plan_executor.go:94 +0xaf