Heroku Provisioner doesn't properly validate variable syntax in a config_vars block

[wdullaer]

I had a rather large terraform plan containing multiple providers.

One of the heroku app resources had the following in the config_vars block

resource "heroku_app" "web" {
  name = "awesome-app"
  config_vars = {
    USERNAME = "${my_username}"
  }
}

Notice how it says "${my_username}" rather than "${var.my_username}"
Due to the size of the total project, I didn't notice this.
terraform validate didn't throw any errors
terraform plan worked just fine

It finally crashen when trying to apply the changes with this rather bizar error

panic: interface conversion: interface {} is nil, not map[string]interface {}                                                                                                                                     
2016/03/16 16:02:52 [DEBUG] terraform-provider-heroku:                                                                                                                                                            
2016/03/16 16:02:52 [DEBUG] terraform-provider-heroku: goroutine 62 [running]:                                                                                                                                    
2016/03/16 16:02:52 [DEBUG] terraform-provider-heroku: panic(0xa74da0, 0xc820224100)                                                                                                                              
2016/03/16 16:02:52 [DEBUG] terraform-provider-heroku:  /opt/go/src/runtime/panic.go:464 +0x3e6                                                                                                                   
2016/03/16 16:02:52 [DEBUG] terraform-provider-heroku: github.com/hashicorp/terraform/builtin/providers/heroku.resourceHerokuAppRead(0xc8202d8540, 0xb3a8c0, 0xc82017c660, 0x0, 0x0)                              
2016/03/16 16:02:52 [DEBUG] terraform-provider-heroku:  /opt/gopath/src/github.com/hashicorp/terraform/builtin/providers/heroku/resource_heroku_app.go:290 +0xf0b                                                 
2016/03/16 16:02:52 [DEBUG] terraform-provider-heroku: github.com/hashicorp/terraform/builtin/providers/heroku.resourceHerokuAppUpdate(0xc8202d8540, 0xb3a8c0, 0xc82017c660, 0x0, 0x0)                            
2016/03/16 16:02:52 [DEBUG] terraform-provider-heroku:  /opt/gopath/src/github.com/hashicorp/terraform/builtin/providers/heroku/resource_heroku_app.go:376 +0x625                                                 
2016/03/16 16:02:52 [DEBUG] terraform-provider-heroku: github.com/hashicorp/terraform/helper/schema.(*Resource).Apply(0xc820107880, 0xc820493b00, 0xc820491de0, 0xb3a8c0, 0xc82017c660, 0xc820493c01, 0x0, 0x0)   
2016/03/16 16:02:52 [DEBUG] terraform-provider-heroku:  /opt/gopath/src/github.com/hashicorp/terraform/helper/schema/resource.go:152 +0x3b9                                                                       
2016/03/16 16:02:52 [DEBUG] terraform-provider-heroku: github.com/hashicorp/terraform/helper/schema.(*Provider).Apply(0xc820344ff0, 0xc820401280, 0xc820493b00, 0xc820491de0, 0x1, 0x0, 0x0)                      
2016/03/16 16:02:52 [DEBUG] terraform-provider-heroku:  /opt/gopath/src/github.com/hashicorp/terraform/helper/schema/provider.go:162 +0x1ed                                                                       
2016/03/16 16:02:52 [DEBUG] terraform-provider-heroku: github.com/hashicorp/terraform/rpc.(*ResourceProviderServer).Apply(0xc8203b49c0, 0xc8204b1a40, 0xc820491e30, 0x0, 0x0)                                     
2016/03/16 16:02:52 [DEBUG] terraform-provider-heroku:  /opt/gopath/src/github.com/hashicorp/terraform/rpc/resource_provider.go:323 +0x76                                                                         
2016/03/16 16:02:52 [DEBUG] terraform-provider-heroku: reflect.Value.call(0xa0a940, 0xaf20f8, 0x13, 0xb3e610, 0x4, 0xc8201ffed8, 0x3, 0x3, 0x0, 0x0, ...)                                                         
2016/03/16 16:02:52 [DEBUG] terraform-provider-heroku:  /opt/go/src/reflect/value.go:435 +0x120d                                                                                                                  
2016/03/16 16:02:52 [DEBUG] terraform-provider-heroku: reflect.Value.Call(0xa0a940, 0xaf20f8, 0x13, 0xc8201ffed8, 0x3, 0x3, 0x0, 0x0, 0x0)                                                                        
2016/03/16 16:02:52 [DEBUG] terraform-provider-heroku:  /opt/go/src/reflect/value.go:303 +0xb1                                                                                                                    
2016/03/16 16:02:52 [DEBUG] terraform-provider-heroku: net/rpc.(*service).call(0xc820107a00, 0xc8201079c0, 0xc8203a1850, 0xc820341880, 0xc8203b49e0, 0x91f5a0, 0xc8204b1a40, 0x16, 0x91f600, 0xc820491e30, ...)   
2016/03/16 16:02:52 [DEBUG] terraform-provider-heroku:  /opt/go/src/net/rpc/server.go:383 +0x1c2                                                                                                                  
2016/03/16 16:02:52 [DEBUG] terraform-provider-heroku: created by net/rpc.(*Server).ServeCodec                                                                                                                    
2016/03/16 16:02:52 [DEBUG] terraform-provider-heroku:  /opt/go/src/net/rpc/server.go:477 +0x49d                                                                                                                  
2016/03/16 16:02:52 [DEBUG] root: eval: *terraform.EvalWriteState                                                                                                                                                 
2016/03/16 16:02:52 [DEBUG] root: eval: *terraform.EvalApplyProvisioners                                                                                                                                          
2016/03/16 16:02:52 [DEBUG] root: eval: *terraform.EvalIf                                                                                                                                                         
2016/03/16 16:02:52 [DEBUG] root: eval: *terraform.EvalWriteDiff                                                                                                                                                  
2016/03/16 16:02:52 [DEBUG] root: eval: *terraform.EvalIf                                                                                                                                                         
2016/03/16 16:02:52 [DEBUG] root: eval: *terraform.EvalWriteState                                                                                                                                                 
2016/03/16 16:02:52 [DEBUG] root: eval: *terraform.EvalApplyPost                                                                                                                                                  
2016/03/16 16:02:52 [DEBUG] /usr/local/bin/terraform-provider-heroku: plugin process exited                                                                                                                       
2016/03/16 16:02:52 [ERROR] root: eval: *terraform.EvalApplyPost, err: 1 error(s) occurred:                                                                                                                       

* heroku_app.integration: unexpected EOF                                                                                                                                                                          
2016/03/16 16:02:52 [ERROR] root: eval: *terraform.EvalSequence, err: 1 error(s) occurred:                                                                                                                        

* heroku_app.integration: unexpected EOF                                                                                                                                                                          
2016/03/16 16:02:52 [ERROR] root: eval: *terraform.EvalOpFilter, err: 1 error(s) occurred:                                                                                                                        

* heroku_app.integration: unexpected EOF                                                                                                                                                                          
2016/03/16 16:02:52 [ERROR] root: eval: *terraform.EvalSequence, err: 1 error(s) occurred:                                                                                                                        

* heroku_app.integration: unexpected EOF                                                                                                                                                                          
2016/03/16 16:02:52 [TRACE] [walkApply] Exiting eval tree: heroku_app.integration                                                                                                                                 
2016/03/16 16:02:52 [DEBUG] vertex provider.heroku (close), got dep: heroku_app.integration                                                                                                                       
2016/03/16 16:02:52 [DEBUG] vertex root, got dep: provider.heroku (close)                                                                                                                                         
2016/03/16 16:02:52 [DEBUG] vertex root, got dep: provider.aws (close)                                                                                                                                            
2016/03/16 16:02:52 [DEBUG] waiting for all plugin processes to complete...                                                                                                                                       
2016/03/16 16:02:52 [DEBUG] /usr/local/bin/terraform-provider-aws: plugin process exited      

It took me a while/day to figure out that there was a variable with an invalid syntax. I suppose the terraform parser should catch this.

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

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