bug on merging with exisitn terraform.tfstate file

[StL-Jim]

Here's the error I get when I try to merge into an existing terraform.tfstate
terraforming cwa --tfstate --merge=terraform.tfstate --profile xxxxxxx
/var/lib/gems/2.3.0/gems/terraforming-0.18.0/lib/terraforming/cli.rb:269:in tfstate': undefined method []' for nil:NilClass (NoMethodError)
from /var/lib/gems/2.3.0/gems/terraforming-0.18.0/lib/terraforming/cli.rb:250:in execute' from /var/lib/gems/2.3.0/gems/terraforming-0.18.0/lib/terraforming/cli.rb:25:in cwa'
from /var/lib/gems/2.3.0/gems/thor-1.0.1/lib/thor/command.rb:27:in run' from /var/lib/gems/2.3.0/gems/thor-1.0.1/lib/thor/invocation.rb:127:in invoke_command'
from /var/lib/gems/2.3.0/gems/thor-1.0.1/lib/thor.rb:392:in dispatch' from /var/lib/gems/2.3.0/gems/thor-1.0.1/lib/thor/base.rb:485:in start'
from /var/lib/gems/2.3.0/gems/terraforming-0.18.0/bin/terraforming:5:in <top (required)>' from /usr/local/bin/terraforming:23:in load'
from /usr/local/bin/terraforming:23:in `

'

[StL-Jim]

Also, I installed using gem install terraforming, here's the list of installed gems
gem list

*** LOCAL GEMS ***

aws-eventstream (1.0.3)
aws-partitions (1.259.0)
aws-sdk-autoscaling (1.30.0)
aws-sdk-cloudwatch (1.31.0)
aws-sdk-core (3.86.0)
aws-sdk-dynamodb (1.41.0)
aws-sdk-ec2 (1.129.0)
aws-sdk-efs (1.23.0)
aws-sdk-elasticache (1.29.0)
aws-sdk-elasticloadbalancing (1.19.0)
aws-sdk-elasticloadbalancingv2 (1.39.0)
aws-sdk-iam (1.32.0)
aws-sdk-kms (1.27.0)
aws-sdk-rds (1.74.0)
aws-sdk-redshift (1.35.0)
aws-sdk-route53 (1.30.0)
aws-sdk-s3 (1.60.1)
aws-sdk-sns (1.21.0)
aws-sdk-sqs (1.23.1)
aws-sigv4 (1.1.0)
bigdecimal (1.2.8)
did_you_mean (1.0.0)
io-console (0.4.5)
jmespath (1.4.0)
json (1.8.3)
minitest (5.8.4)
multi_json (1.12.2)
net-telnet (0.1.1)
power_assert (0.2.7)
psych (2.0.17)
rake (10.5.0)
rdoc (4.2.1)
terraforming (0.18.0)
test-unit (3.1.7)
thor (1.0.1)

[richstokes]

Running into something similar here. Did you ever find a solution?

Traceback (most recent call last):
	9: from /usr/local/bin/terraforming:23:in `<main>'
	8: from /usr/local/bin/terraforming:23:in `load'
	7: from /Library/Ruby/Gems/2.6.0/gems/terraforming-0.18.0/bin/terraforming:5:in `<top (required)>'
	6: from /Library/Ruby/Gems/2.6.0/gems/thor-1.0.1/lib/thor/base.rb:485:in `start'
	5: from /Library/Ruby/Gems/2.6.0/gems/thor-1.0.1/lib/thor.rb:392:in `dispatch'
	4: from /Library/Ruby/Gems/2.6.0/gems/thor-1.0.1/lib/thor/invocation.rb:127:in `invoke_command'
	3: from /Library/Ruby/Gems/2.6.0/gems/thor-1.0.1/lib/thor/command.rb:27:in `run'
	2: from /Library/Ruby/Gems/2.6.0/gems/terraforming-0.18.0/lib/terraforming/cli.rb:120:in `iamu'
	1: from /Library/Ruby/Gems/2.6.0/gems/terraforming-0.18.0/lib/terraforming/cli.rb:250:in `execute'
/Library/Ruby/Gems/2.6.0/gems/terraforming-0.18.0/lib/terraforming/cli.rb:269:in `tfstate': undefined method `[]' for nil:NilClass (NoMethodError)

[LunaticZorr]

Same error here too

Traceback (most recent call last):
	9: from /usr/local/bin/terraforming:23:in `<main>'
	8: from /usr/local/bin/terraforming:23:in `load'
	7: from /var/lib/gems/2.5.0/gems/terraforming-0.18.0/bin/terraforming:5:in `<top (required)>'
	6: from /usr/lib/ruby/vendor_ruby/thor/base.rb:444:in `start'
	5: from /usr/lib/ruby/vendor_ruby/thor.rb:369:in `dispatch'
	4: from /usr/lib/ruby/vendor_ruby/thor/invocation.rb:126:in `invoke_command'
	3: from /usr/lib/ruby/vendor_ruby/thor/command.rb:27:in `run'
	2: from /var/lib/gems/2.5.0/gems/terraforming-0.18.0/lib/terraforming/cli.rb:215:in `vpc'
	1: from /var/lib/gems/2.5.0/gems/terraforming-0.18.0/lib/terraforming/cli.rb:250:in `execute'
/var/lib/gems/2.5.0/gems/terraforming-0.18.0/lib/terraforming/cli.rb:269:in `tfstate': undefined method `[]' for nil:NilClass (NoMethodError)

[shanezeller]

I am getting parse error in Multi-json thrign to merge anything.
vagrant@ubuntu1804:~/SpecialProjects/Output$ terraforming alb --tfstate --merge=.terraform.tfstate --overwrite
Traceback (most recent call last):
11: from /usr/local/bin/terraforming:23:in <main>' 10: from /usr/local/bin/terraforming:23:in load'
9: from /var/lib/gems/2.5.0/gems/terraforming-0.18.0/bin/terraforming:5:in <top (required)>' 8: from /var/lib/gems/2.5.0/gems/thor-1.0.1/lib/thor/base.rb:485:in start'
7: from /var/lib/gems/2.5.0/gems/thor-1.0.1/lib/thor.rb:392:in dispatch' 6: from /var/lib/gems/2.5.0/gems/thor-1.0.1/lib/thor/invocation.rb:127:in invoke_command'
5: from /var/lib/gems/2.5.0/gems/thor-1.0.1/lib/thor/command.rb:27:in run' 4: from /var/lib/gems/2.5.0/gems/terraforming-0.18.0/lib/terraforming/cli.rb:15:in alb'
3: from /var/lib/gems/2.5.0/gems/terraforming-0.18.0/lib/terraforming/cli.rb:250:in execute' 2: from /var/lib/gems/2.5.0/gems/terraforming-0.18.0/lib/terraforming/cli.rb:267:in tfstate'
1: from /var/lib/gems/2.5.0/gems/multi_json-1.12.2/lib/multi_json.rb:122:in load' /var/lib/gems/2.5.0/gems/multi_json-1.12.2/lib/multi_json/adapter.rb:20:in load': JSON::ParserError (MultiJson::ParseError)

[tingwei628]

If there's no property "modules" in terraform.tfstate file, the following codes would cause NoMethodError problem.

tfstate["modules"][0]["resources"] = tfstate["modules"][0]["resources"].merge(klass.tfstate)

UPDATE
I found another tool to merge Terraform state files into one.