[BUG] falco will crush with the fastly service without VCL in the terraform planned output

[Shinyaigeek]

Describe the problem

falco will crush if falco get the fastly service without VCL in the terraform planned output. I have the project which have the multiple fastly services managed in the single terraform state. These fastly services include the service which does not have VCL.

I tried to introduce falco linter/tester into this project, but when I run terraform show -json planned.out | falco terraform command, falco will crush with the below error output.

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x2 addr=0x0 pc=0x1008da520]

goroutine 1 [running]:
main.(*Runner).run(0x140002ae690, 0x2?, 0x0, 0x1)
        /home/runner/work/falco/falco/cmd/falco/runner.go:227 +0x30
main.(*Runner).Run(0x140002ae690, {0x100bf16c0?, 0x140007b26c0})
        /home/runner/work/falco/falco/cmd/falco/runner.go:211 +0x180
main.runLint(0x140002ae690, {0x100bf16c0?, 0x140007b26c0?})
        /home/runner/work/falco/falco/cmd/falco/main.go:145 +0x30
main.main()
        /home/runner/work/falco/falco/cmd/falco/main.go:131 +0x84c

falco's linter/tester/simulator expect all fastly service to have VCL (ref: https://github.com/ysugimoto/falco/blob/main/resolver/terraform.go#L29), so falco will crush when falco encounter the fastly service which does not have VCL. I think falco should filter the fastly services which does not have VCL in advance.

VCL code that cause the problem

This is not related to VCL, but I made simple repro; https://github.com/Shinyaigeek/falco-with-multiple-services

Desktop (please complete the following information):

• OS: MacOS arm64
• Shell zsh

[Shinyaigeek]

I sent the PR to fix this issue in #186