Plugin crashes when trying to decrease virtual machine's raw disk size

[rovilu]

Description

There is a possibility to add volatile disk to opennebula_virtual_machine resource, which shares the virtual machine's lifecycle. The documentation says that if size disk size value is changed on an existing resource, it must be bigger than the previous one.

If the new value is still smaller than the previous one, on "terraform apply", the plugin crashes producing a huge error log:

Stack trace from the terraform-provider-opennebula_v1.3.0 plugin:

panic: runtime error: index out of range [1] with length 1

goroutine 113 [running]:
github.com/OpenNebula/terraform-provider-opennebula/opennebula.updateDisk({0xe86ba8, 0xc0003067e0}, 0xc000163dc0?, {0xc44800?, 0xc000163dc0?})
github.com/OpenNebula/terraform-provider-opennebula/opennebula/resource_opennebula_virtual_machine.go:1724 +0x19b3
github.com/OpenNebula/terraform-provider-opennebula/opennebula.resourceOpennebulaVirtualMachineUpdateCustom({0xe86ba8, 0xc0003067e0}, 0xc00004c100, {0xc44800, 0xc000163dc0}, 0xd93038)
github.com/OpenNebula/terraform-provider-opennebula/opennebula/resource_opennebula_virtual_machine.go:1321 +0x2195
github.com/OpenNebula/terraform-provider-opennebula/opennebula.resourceOpennebulaVirtualMachineUpdate({0xe86ba8, 0xc0003067e0}, 0x0?, {0xc44800, 0xc000163dc0})
github.com/OpenNebula/terraform-provider-opennebula/opennebula/resource_opennebula_virtual_machine.go:1101 +0x39
github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema.(*Resource).update(0xc000488540, {0xe86be0, 0xc000889bf0}, 0xd?, {0xc44800, 0xc000163dc0})
github.com/hashicorp/terraform-plugin-sdk/v2@v2.24.1/helper/schema/resource.go:741 +0x12e
github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema.(*Resource).Apply(0xc000488540, {0xe86be0, 0xc000889bf0}, 0xc00071a8f0, 0xc00004d600, {0xc44800, 0xc000163dc0})
github.com/hashicorp/terraform-plugin-sdk/v2@v2.24.1/helper/schema/resource.go:847 +0x82c
github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema.(*GRPCProviderServer).ApplyResourceChange(0xc000223758, {0xe86be0?, 0xc000889ad0?}, 0xc000528730)
github.com/hashicorp/terraform-plugin-sdk/v2@v2.24.1/helper/schema/grpc_provider.go:1021 +0xe3c
github.com/hashicorp/terraform-plugin-go/tfprotov5/tf5server.(*server).ApplyResourceChange(0xc0003710e0, {0xe86be0?, 0xc0008892c0?}, 0xc00014c310)
github.com/hashicorp/terraform-plugin-go@v0.14.1/tfprotov5/tf5server/server.go:818 +0x574
github.com/hashicorp/terraform-plugin-go/tfprotov5/internal/tfplugin5._Provider_ApplyResourceChange_Handler({0xd08360?, 0xc0003710e0}, {0xe86be0, 0xc0008892c0}, 0xc00014c2a0, 0x0)
github.com/hashicorp/terraform-plugin-go@v0.14.1/tfprotov5/internal/tfplugin5/tfplugin5_grpc.pb.go:385 +0x170
google.golang.org/grpc.(*Server).processUnaryRPC(0xc0003783c0, {0xe89de0, 0xc00050a1a0}, 0xc00040c5a0, 0xc0004a25a0, 0x13766c0, 0x0)
google.golang.org/grpc@v1.50.1/server.go:1340 +0xd13
google.golang.org/grpc.(*Server).handleStream(0xc0003783c0, {0xe89de0, 0xc00050a1a0}, 0xc00040c5a0, 0x0)
google.golang.org/grpc@v1.50.1/server.go:1713 +0xa1b
google.golang.org/grpc.(*Server).serveStreams.func1.2()
google.golang.org/grpc@v1.50.1/server.go:965 +0x98
created by google.golang.org/grpc.(*Server).serveStreams.func1
google.golang.org/grpc@v1.50.1/server.go:963 +0x28a

Error: The terraform-provider-opennebula_v1.3.0 plugin crashed!

This is always indicative of a bug within the plugin. It would be immensely
helpful if you could report the crash with the plugin's maintainers so that it
can be fixed. The output above should help diagnose the issue.

Terraform and Provider version

Terraform v1.6.2
OpenNebula provider v1.3.0

Affected resources and data sources

opennebula_virtual_machine

Terraform configuration

No response

Expected behavior

Error is raised by the plugin telling that the disk size value should be bigger than the previous one.

Actual behavior

The plugin crashes.

Steps to Reproduce

1. Create "opennebula_virtual_machine" resource with raw disk of a random size, e.g. using sample:

resource "opennebula_virtual_machine" "test" {
....

  disk {
    size            = 10240
    driver          = "raw"
    dev_prefix      = "sd"
    volatile_type   = "fs"
    volatile_format = "raw"
  }

....

2. Create the virtual machine (terraform plan; terraform apply)
3. Change the "size" parameter value in the "disk" block to the smaller one, e.g.

....
  disk {
    size            = 5120
    driver          = "raw"
    dev_prefix      = "sd"
    volatile_type   = "fs"
    volatile_format = "raw"
  }
.....

4. Apply changes (terraform plan; terraform apply) (multiple times if needed)
5. Enjoy the errors.

Debug output

No response

Panic output

No response

Important factoids

No response

References

No response

[github-actions]

This issue is stale because it has been open for 30 days with no activity and it has not the 'status: confirmed' label or it is not in a milestone. Remove the 'status: stale' label or comment, or this will be closed in 5 days.

[rovilu]

Up

[github-actions]

This issue is stale because it has been open for 30 days with no activity and it has not the 'status: confirmed' label or it is not in a milestone. Remove the 'status: stale' label or comment, or this will be closed in 5 days.

[treywelsh]

I think it would be better to fix this at the same time we externalize the disk resource as it's not a critical bug
#525