Provider crashes during import of transfer endpoint configuration

[vlad-vinnik]

Issue Description

When executing the terraform import command for the doublecloud_transfer_endpoint resource, the provider plugin crashes. Here is the command used and the resulting output:

Command Used & Output

terraform import doublecloud_transfer_endpoint.name <endpoint_id>

Error: Request cancelled

The plugin6.(*GRPCProvider).ReadResource request was cancelled.

Stack trace from the terraform-provider-doublecloud_v0.1.26 plugin:

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x2 addr=0x18 pc=0x1033acd3c]

goroutine 70 [running]:
github.com/doublecloud/terraform-provider-doublecloud/internal/provider.parseTransferEndpointClickhouseConnection({0x103709620?, 0x140001e7260?}, 0x100000002?, 0x14000609be0?)
        github.com/doublecloud/terraform-provider-doublecloud/internal/provider/transfer_endpoint_clickhouse.go:281 +0x5c
github.com/doublecloud/terraform-provider-doublecloud/internal/provider.(*TransferEndpointModel).parseTransferEndpoint(0x140002627e0, {0x1038a7c58, 0x140006dc270}, 0x14000728780)
        github.com/doublecloud/terraform-provider-doublecloud/internal/provider/transfer_endpoint_resource.go:579 +0x19c0
github.com/doublecloud/terraform-provider-doublecloud/internal/provider.(*TransferEndpointResource).Read(0x140006855b0, {0x1038a7c58, 0x140006dc270}, {{{{0x1038acef0, 0x140000c87b0}, {0x103710aa0, 0x140003dca50}}, {0x1038af190, 0x140006883c0}}, 0x1400011a468, ...}, ...)
        github.com/doublecloud/terraform-provider-doublecloud/internal/provider/transfer_endpoint_resource.go:257 +0x248
github.com/hashicorp/terraform-plugin-framework/internal/fwserver.(*Server).ReadResource(0x14000133d40, {0x1038a7c58, 0x140006dc270}, 0x140006dc2d0, 0x140006b3690)
        github.com/hashicorp/terraform-plugin-framework@v1.8.0/internal/fwserver/server_readresource.go:101 +0x510
github.com/hashicorp/terraform-plugin-framework/internal/proto6server.(*Server).ReadResource(0x14000133d40, {0x1038a7c58?, 0x140006dc180?}, 0x140006867c0)
        github.com/hashicorp/terraform-plugin-framework@v1.8.0/internal/proto6server/server_readresource.go:55 +0x2e0
github.com/hashicorp/terraform-plugin-go/tfprotov6/tf6server.(*server).ReadResource(0x1400026a780, {0x1038a7c58?, 0x140006d9770?}, 0x1400009a840)
        github.com/hashicorp/terraform-plugin-go@v0.22.2/tfprotov6/tf6server/server.go:776 +0x3c8
github.com/hashicorp/terraform-plugin-go/tfprotov6/internal/tfplugin6._Provider_ReadResource_Handler({0x103869d60, 0x1400026a780}, {0x1038a7c58, 0x140006d9770}, 0x140005ee600, 0x0)
        github.com/hashicorp/terraform-plugin-go@v0.22.2/tfprotov6/internal/tfplugin6/tfplugin6_grpc.pb.go:482 +0x1c0
google.golang.org/grpc.(*Server).processUnaryRPC(0x1400019b800, {0x1038a7c58, 0x140006d96e0}, {0x1038ae020, 0x140001f0480}, 0x140006d78c0, 0x140003dda40, 0x103f856a8, 0x0)
        google.golang.org/grpc@v1.65.0/server.go:1379 +0xb58
google.golang.org/grpc.(*Server).handleStream(0x1400019b800, {0x1038ae020, 0x140001f0480}, 0x140006d78c0)
        google.golang.org/grpc@v1.65.0/server.go:1790 +0xb20
google.golang.org/grpc.(*Server).serveStreams.func2.1()
        google.golang.org/grpc@v1.65.0/server.go:1029 +0x8c
created by google.golang.org/grpc.(*Server).serveStreams.func2 in goroutine 25
        google.golang.org/grpc@v1.65.0/server.go:1040 +0x13c

Error: The terraform-provider-doublecloud_v0.1.26 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.

Expected Behaviour

The resource import should work normally without the provider plugin crash.

Environment

• Terraform version: 1.8.15
• Terraform provider version: 0.1.26
• DoubleCloud resource type: doublecloud_transfer_endpoint