Hi,
I hope someone can help me. I’m having some problems using CustomizeDiff with calculated fields in that it panics due to a nil pointer.
My CustomizeDiff function looks like this:
CustomizeDiff: func(ctx context.Context, d *schema.ResourceDiff, meta interface{}) error {
old, new := d.GetChange("network_interface")
oldList := old.([]interface{})
newList := new.([]interface{})
// If the new list is shorter than the old list we
// want to force new.
if len(newList) < len(oldList) {
d.ForceNew("network_interface")
return nil
}
for i, oi := range oldList {
oiB := oi.(map[string]interface{})
niB := newList[i].(map[string]interface{})
if oiB["type"] != niB["type"] {
d.ForceNew(fmt.Sprintf("network_interface.%d.type", i))
}
if oiB["ip_address_family"] != niB["ip_address_family"] {
d.ForceNew(fmt.Sprintf("network_interface.%d.ip_address_family", i))
}
if oiB["network"] != niB["network"] {
d.ForceNew(fmt.Sprintf("network_interface.%d.network", i))
}
}
return nil
},
In essence, it is attempting to detect a few scenarios where we know we need to re-create the resource: a) when we’ve removed an item from the list b) any of the items in the list have certain fields changed c) the order of the list has changed.
This code mostly works in manual and automated tests. The network field is the ID of another resource. If the creation of that resource happens during the same plan/apply as changing the value of network then the provider crashes:
2020-08-23T21:17:56.335+0100 [DEBUG] plugin.terraform-provider-x: panic: runtime error: invalid memory address or nil pointer dereference
2020-08-23T21:17:56.335+0100 [DEBUG] plugin.terraform-provider-x: [signal SIGSEGV: segmentation violation code=0x1 addr=0x28 pc=0xabbf50]
2020-08-23T21:17:56.335+0100 [DEBUG] plugin.terraform-provider-x:
2020-08-23T21:17:56.335+0100 [DEBUG] plugin.terraform-provider-x: goroutine 54 [running]:
2020-08-23T21:17:56.335+0100 [DEBUG] plugin.terraform-provider-x: github.com/hashicorp/terraform-plugin-sdk/v2/internal/helper/plugin.(*GRPCProviderServer).PlanResourceChange(0xc00000e280, 0xd7ae20, 0xc0000813c0, 0xc00021c000, 0xc00000e280, 0xc00000e290, 0xc90498)
2020-08-23T21:17:56.335+0100 [DEBUG] plugin.terraform-provider-x: /home/stuart/Projects/terraform-provider-x/vendor/github.com/hashicorp/terraform-plugin-sdk/v2/internal/helper/plugin/grpc_provider.go:797 +0x1110
2020-08-23T21:17:56.335+0100 [DEBUG] plugin.terraform-provider-x: github.com/hashicorp/terraform-plugin-sdk/v2/internal/tfplugin5._Provider_PlanResourceChange_Handler.func1(0xd7ae20, 0xc0000813c0, 0xc22080, 0xc00021c000, 0xc0000813c0, 0xba1e00, 0xc00009cd01, 0xc0003e4d80)
2020-08-23T21:17:56.335+0100 [DEBUG] plugin.terraform-provider-x: /home/stuart/Projects/terraform-provider-x/vendor/github.com/hashicorp/terraform-plugin-sdk/v2/internal/tfplugin5/tfplugin5.pb.go:3294 +0x86
2020-08-23T21:17:56.335+0100 [DEBUG] plugin.terraform-provider-x: github.com/hashicorp/terraform-plugin-sdk/v2/plugin.Serve.func3.1(0xd7aee0, 0xc00057e390, 0xc22080, 0xc00021c000, 0xc0003e4d60, 0xc0003e4d80, 0xc000521ba0, 0x526718, 0xbf8f40, 0xc00057e390)
2020-08-23T21:17:56.335+0100 [DEBUG] plugin.terraform-provider-x: /home/stuart/Projects/terraform-provider-x/vendor/github.com/hashicorp/terraform-plugin-sdk/v2/plugin/serve.go:76 +0x87
2020-08-23T21:17:56.335+0100 [DEBUG] plugin.terraform-provider-x: github.com/hashicorp/terraform-plugin-sdk/v2/internal/tfplugin5._Provider_PlanResourceChange_Handler(0xc30860, 0xc00000e280, 0xd7aee0, 0xc00057e390, 0xc00009cde0, 0xc000346d40, 0xd7aee0, 0xc00057e390, 0xc000447000, 0x7d5)
2020-08-23T21:17:56.335+0100 [DEBUG] plugin.terraform-provider-x: /home/stuart/Projects/terraform-provider-x/vendor/github.com/hashicorp/terraform-plugin-sdk/v2/internal/tfplugin5/tfplugin5.pb.go:3296 +0x14b
2020-08-23T21:17:56.335+0100 [DEBUG] plugin.terraform-provider-x: google.golang.org/grpc.(*Server).processUnaryRPC(0xc000268a80, 0xd836a0, 0xc000107b00, 0xc000188600, 0xc000192c30, 0x129d168, 0x0, 0x0, 0x0)
2020-08-23T21:17:56.336+0100 [DEBUG] plugin.terraform-provider-x: /home/stuart/Projects/terraform-provider-x/vendor/google.golang.org/grpc/server.go:1171 +0x50a
2020-08-23T21:17:56.336+0100 [DEBUG] plugin.terraform-provider-x: google.golang.org/grpc.(*Server).handleStream(0xc000268a80, 0xd836a0, 0xc000107b00, 0xc000188600, 0x0)
2020-08-23T21:17:56.336+0100 [DEBUG] plugin.terraform-provider-x: /home/stuart/Projects/terraform-provider-x/vendor/google.golang.org/grpc/server.go:1494 +0xccd
2020-08-23T21:17:56.336+0100 [DEBUG] plugin.terraform-provider-x: google.golang.org/grpc.(*Server).serveStreams.func1.2(0xc00012a360, 0xc000268a80, 0xd836a0, 0xc000107b00, 0xc000188600)
2020-08-23T21:17:56.336+0100 [DEBUG] plugin.terraform-provider-x: /home/stuart/Projects/terraform-provider-x/vendor/google.golang.org/grpc/server.go:834 +0xa1
2020-08-23T21:17:56.336+0100 [DEBUG] plugin.terraform-provider-x: created by google.golang.org/grpc.(*Server).serveStreams.func1
2020-08-23T21:17:56.336+0100 [DEBUG] plugin.terraform-provider-x: /home/stuart/Projects/terraform-provider-x/vendor/google.golang.org/grpc/server.go:832 +0x204
The crash appears to be happening in line 796 of grpc_provider.go here (at if v.NewExtra != nil {):
newExtra := map[string]interface{}{}
for k, v := range diff.Attributes {
if v.NewExtra != nil {
newExtra[k] = v.NewExtra
}
}
privateMap[newExtraKey] = newExtra
Sticking in a debug Printf I can see that the value of network is nil:
2020/08/23 21:17:56 [DEBUG]: diff.Attributes: map[string]*terraform.ResourceAttrDiff{"network_interface.1.network":<nil>}
Am I doing something wrong in CustomizeDiff to cause this? Has anyone come across something like this before?
Any help is appreciated!