panic: runtime error if terraform output contains null.

[goruha]

Steps to reproduce

1. Create an empty dir with terraform file example.tf

output "foo" {
  value = "foo"
}

output "bar" {
  value = null
}

2. Run

terraform plan
terraform apply
terraform output --json > output.json

3. Run

terraform-docs markdown ./ --output-values --output-values-from ./output.json

Expected

• Successfully generated markdown

Exists

• Error

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x93e475]

goroutine 1 [running]:
github.com/terraform-docs/terraform-docs/terraform.loadOutputs(0xc000165b80, 0xc000002180)
	/home/runner/work/terraform-docs/terraform-docs/terraform/load.go:298 +0x2d5
github.com/terraform-docs/terraform-docs/terraform.loadModuleItems(0x7ffdd7128646?, 0xc0000022a8?)
	/home/runner/work/terraform-docs/terraform-docs/terraform/load.go:70 +0x106
github.com/terraform-docs/terraform-docs/terraform.LoadWithOptions(0xc000002180)
	/home/runner/work/terraform-docs/terraform-docs/terraform/load.go:41 +0x38
github.com/terraform-docs/terraform-docs/internal/cli.generateContent(0xc000002180)
	/home/runner/work/terraform-docs/terraform-docs/internal/cli/run.go:326 +0x1c
github.com/terraform-docs/terraform-docs/internal/cli.(*Runtime).RunEFunc(0xc00023b540, 0x0?, {0x0?, 0x0?, 0x0?})
	/home/runner/work/terraform-docs/terraform-docs/internal/cli/run.go:134 +0x1e5
github.com/spf13/cobra.(*Command).execute(0xc000005200, {0xc00023b800, 0x4, 0x4})
	/home/runner/go/pkg/mod/github.com/spf13/[email protected]/command.go:983 +0xabc
github.com/spf13/cobra.(*Command).ExecuteC(0xc000004300)
	/home/runner/go/pkg/mod/github.com/spf13/[email protected]/command.go:1115 +0x3ff
github.com/spf13/cobra.(*Command).Execute(...)
	/home/runner/go/pkg/mod/github.com/spf13/[email protected]/command.go:1039
github.com/terraform-docs/terraform-docs/cmd.Execute()
	/home/runner/work/terraform-docs/terraform-docs/cmd/root.go:37 +0x1c
main.main()
	/home/runner/work/terraform-docs/terraform-docs/main.go:20 +0x13

Reason

If the output value is null,, it would be skipped in terraform output.

So output.json file will be

{
  "foo": {
    "sensitive": false,
    "type": "string",
    "value": "foo"
  }
}

Point in code to fix https://github.com/terraform-docs/terraform-docs/blob/master/terraform/load.go#L298

Versions

• terraform v1.2.2
• terraform docs v0.17.0 795d369 linux/amd64