Terraform crash on Mac OSX

[ghost]

This issue was originally opened by @wiwa1978 as hashicorp/terraform#19531. It was migrated here as a result of the provider split. The original body of the issue is below.

---

Terraform version: 0.11.10
Go runtime version: go1.11.2
MAC OSX: 10.14.1

Use case: Trying to create a virtual machine on vSphere.

The attached zip file contains the files "ubuntu-01.tf" and "variables.tf" that can be used for debugging.

Archive.zip
crash.log

Stack Trace:

2018-12-02T19:53:28.196+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: panic: interface conversion: interface {} is nil, not string
2018-12-02T19:53:28.196+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: 
2018-12-02T19:53:28.196+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: goroutine 199 [running]:
2018-12-02T19:53:28.196+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: github.com/terraform-providers/terraform-provider-vsphere/vsphere/internal/helper/structure.SliceInterfacesToStrings(0xc42030d310, 0x1, 0x1, 0x1de20a0, 0xc42069c600, 0x0)
2018-12-02T19:53:28.196+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: 	/opt/teamcity-agent/work/222ea50a1b4f75f4/src/github.com/terraform-providers/terraform-provider-vsphere/vsphere/internal/helper/structure/structure_helper.go:35 +0x1a6
2018-12-02T19:53:28.196+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: github.com/terraform-providers/terraform-provider-vsphere/vsphere/internal/vmworkflow.expandCustomizationGlobalIPSettings(0xc4202e2e00, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
2018-12-02T19:53:28.196+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: 	/opt/teamcity-agent/work/222ea50a1b4f75f4/src/github.com/terraform-providers/terraform-provider-vsphere/vsphere/internal/vmworkflow/virtual_machine_customize_subresource.go:272 +0xa4
2018-12-02T19:53:28.197+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: github.com/terraform-providers/terraform-provider-vsphere/vsphere/internal/vmworkflow.ExpandCustomizationSpec(0xc4202e2e00, 0xc420523700, 0xa, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, ...)
2018-12-02T19:53:28.197+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: 	/opt/teamcity-agent/work/222ea50a1b4f75f4/src/github.com/terraform-providers/terraform-provider-vsphere/vsphere/internal/vmworkflow/virtual_machine_customize_subresource.go:476 +0x9d
2018-12-02T19:53:28.197+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: github.com/terraform-providers/terraform-provider-vsphere/vsphere.resourceVSphereVirtualMachineCreateClone(0xc4202e2e00, 0x1e73b80, 0xc420436ff0, 0x1de20a0, 0xc42069c720, 0x0)
2018-12-02T19:53:28.197+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: 	/opt/teamcity-agent/work/222ea50a1b4f75f4/src/github.com/terraform-providers/terraform-provider-vsphere/vsphere/resource_vsphere_virtual_machine.go:1106 +0x1c33
2018-12-02T19:53:28.197+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: github.com/terraform-providers/terraform-provider-vsphere/vsphere.resourceVSphereVirtualMachineCreate(0xc4202e2e00, 0x1e73b80, 0xc420436ff0, 0xc4202e2e00, 0x0)
2018-12-02T19:53:28.197+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: 	/opt/teamcity-agent/work/222ea50a1b4f75f4/src/github.com/terraform-providers/terraform-provider-vsphere/vsphere/resource_vsphere_virtual_machine.go:238 +0x1f7
2018-12-02T19:53:28.197+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: github.com/terraform-providers/terraform-provider-vsphere/vendor/github.com/hashicorp/terraform/helper/schema.(*Resource).Apply(0xc420285340, 0xc4202bb040, 0xc42069c3e0, 0x1e73b80, 0xc420436ff0, 0x1, 0xc420434b10, 0x0)
2018-12-02T19:53:28.197+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: 	/opt/teamcity-agent/work/222ea50a1b4f75f4/src/github.com/terraform-providers/terraform-provider-vsphere/vendor/github.com/hashicorp/terraform/helper/schema/resource.go:227 +0x364
2018-12-02T19:53:28.197+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: github.com/terraform-providers/terraform-provider-vsphere/vendor/github.com/hashicorp/terraform/helper/schema.(*Provider).Apply(0xc420285b90, 0xc4202baff0, 0xc4202bb040, 0xc42069c3e0, 0x340e000, 0x0, 0x0)
2018-12-02T19:53:28.197+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: 	/opt/teamcity-agent/work/222ea50a1b4f75f4/src/github.com/terraform-providers/terraform-provider-vsphere/vendor/github.com/hashicorp/terraform/helper/schema/provider.go:283 +0xa4
2018-12-02T19:53:28.197+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: github.com/terraform-providers/terraform-provider-vsphere/vendor/github.com/hashicorp/terraform/plugin.(*ResourceProviderServer).Apply(0xc4207c7500, 0xc42069c380, 0xc42030d1d0, 0x0, 0x0)
2018-12-02T19:53:28.197+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: 	/opt/teamcity-agent/work/222ea50a1b4f75f4/src/github.com/terraform-providers/terraform-provider-vsphere/vendor/github.com/hashicorp/terraform/plugin/resource_provider.go:527 +0x57
2018-12-02T19:53:28.197+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: reflect.Value.call(0xc42005b920, 0xc42000c008, 0x13, 0x20fdf68, 0x4, 0xc42052cf20, 0x3, 0x3, 0x0, 0x0, ...)
2018-12-02T19:53:28.197+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: 	/usr/local/go/src/reflect/value.go:434 +0x905
2018-12-02T19:53:28.197+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: reflect.Value.Call(0xc42005b920, 0xc42000c008, 0x13, 0xc4203f8f20, 0x3, 0x3, 0xc4204cd5c0, 0xc4203f8f28, 0xc420182340)
2018-12-02T19:53:28.197+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: 	/usr/local/go/src/reflect/value.go:302 +0xa4
2018-12-02T19:53:28.197+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: net/rpc.(*service).call(0xc4207c2040, 0xc420082050, 0xc42080c0b0, 0xc42030e000, 0xc420714020, 0x1d8f2e0, 0xc42069c380, 0x16, 0x1d8f320, 0xc42030d1d0, ...)
2018-12-02T19:53:28.197+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: 	/usr/local/go/src/net/rpc/server.go:381 +0x142
2018-12-02T19:53:28.197+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: created by net/rpc.(*Server).ServeCodec
2018-12-02T19:53:28.197+0100 [DEBUG] plugin.terraform-provider-vsphere_v1.5.0_x4: 	/usr/local/go/src/net/rpc/server.go:475 +0x36b

[bill-rich]

Dup of #643