Crash when using ssh connection over HTTP proxy

[alisdair]

Thanks for working on this feature. I was doing some testing last days and I found some issues during the provisioning of files. I was not sure if opening a new bug or continuing with the conversation here, so let me know if I need to move to a new one.

Terraform version

• Terraform v1.3.0-dev on windows_amd64.
• Terraform v1.3.0-dev on linux_amd64.

Debug Output

aws_instance.test: Provisioning with 'file'...
2022-05-03T08:59:29.827+0800 [INFO]  using private key for authentication
panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xc0000005 code=0x0 addr=0x18 pc=0x1f545d8]

goroutine 167 [running]:
github.com/hashicorp/terraform/internal/communicator/ssh.(*Communicator).Connect(0xc002ff7240, {0x0, 0x0})
        C:/Users/test/Desktop/terraform/internal/communicator/ssh/communicator.go:176 +0x658
github.com/hashicorp/terraform/internal/builtin/provisioners/file.copyFiles.func1()
        C:/Users/test/Desktop/terraform/internal/builtin/provisioners/file/resource_provisioner.go:159 +0x26
github.com/hashicorp/terraform/internal/communicator.Retry.func1()
        C:/Users/test/Desktop/terraform/internal/communicator/communicator.go:112 +0x1d8
created by github.com/hashicorp/terraform/internal/communicator.Retry
        C:/Users/test/Desktop/terraform/internal/communicator/communicator.go:95 +0x10f

Expected Behavior

The file provisioner should copy the file to the remote system during the deployment.

Actual Behavior

If the proxy is configured on the connection level, the provisioning of the file is crashing the terraform binary.
This behavior is happening both in Windows and Linux with the terraform binary compiled from clean sources (git clone && go build).

If the proxy configuration is removed from the connection block the file is copied successfully to the remote system. If the provisioner block is removed the execution finish without crashing using the proxy as intended.

Steps to Reproduce

1. Create a basic deployment tf file for AWS:

provider "aws" {
  region = "eu-central-1"
}

resource "aws_instance" "test" {
    instance_type                       = "t2.micro"
    ami                                       = "ami-0006ba1ba3732dd33"
    key_name                             = "test"
    vpc_security_group_ids        = ["allowSSH-sg"]
    associate_public_ip_address = "true"
    availability_zone                   = "eu-central-1a"    
	
	connection {
	  host = self.public_ip
	  type = "ssh"
	  user = "ec2-user"
	  private_key = file("test")
	  timeout = "5m"
	  proxy_scheme = "http"
	  proxy_host   = "myproxy.com"
	  proxy_port   = 8000	  
	}

	# Copies the file
	provisioner "file" {
		source      = "files/test.sh"
		destination = "/tmp/test.sh"
	}
	
	provisioner "remote-exec" {
		inline = [
		  "echo finished"
		]
	}
}

2. run terraform apply and the execution should crash during the provisioning of the file.

Originally posted by @s0rtega in #30274 (comment)

[alisdair]

@s0rtega Thanks for reporting this! I've just merged a fix which will be included in the upcoming 1.2.0-rc1 release.

[s0rtega]

@alisdair I can confirm that now is working as intended. Thanks for the quick fix and the work here.

[github-actions]

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