[BUG] Generated Ruby client contains syntax errors when option for enum includes single-quote

Created by: autopp

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• What's the version of OpenAPI Generator used?
• Have you search for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Bounty to sponsor the fix (example)

Description

When enum contains item with odd number of single-quote, the generated Ruby client code contains syntax errors.

openapi-generator version

$ java -jar modules/openapi-generator-cli/target/openapi-generator-cli.jar version
4.0.0-SNAPSHOT

$ git log --oneline -n 1
dd3e6c6a3b (HEAD -> master, origin/master, origin/HEAD, autopp/master) Use actual value of generateSourceCodeOnly in python generator. (#2015)

OpenAPI declaration file content or url

See: https://gist.github.com/autopp/f1c6f438a050148cefe3d6cbbc0f8a81

The point to notice in this example is that ' is included in two enums.

Command line used for generation

$ java -jar modules/openapi-generator-cli/target/openapi-generator-cli.jar generate --skip-validate-spec -g ruby -o /tmp/gem -i 'https://gist.githubusercontent.com/autopp/f1c6f438a050148cefe3d6cbbc0f8a81/raw/4c8cce86d5b258ec08490b2aa28e59400c854150/swagger.yml'

Steps to reproduce

1. Run the above command to generate client code for Ruby.
2. Run ruby -c /tmp/gem/lib/openapi_client/models/x.rb and ruby -c /tmp/gem/lib/openapi_client/api/default_api.rb to check syntax of the generated model code.
3. Get errors in lib/openapi_client/models/x.rb and lib/openapi_client/api/default_api.rb:

   /tmp/gem/lib/openapi_client/models/x.rb:86: syntax error, unexpected tCONSTANT, expecting ']'
   ...mAttributeValidator.new('String', ['''])
   ...                         ^~~~~~
   /tmp/gem/lib/openapi_client/models/x.rb:86: syntax error, unexpected ']', expecting keyword_end
   ...teValidator.new('String', ['''])
   ... 
                                ^
   
   /tmp/gem/lib/openapi_client/api/default_api.rb:37: syntax error, unexpected tIDENTIFIER, expecting ']'
   ...] && !['''].include?(opts[:'foo'])
   ...                            ^~~
   /tmp/gem/lib/openapi_client/api/default_api.rb:38: syntax error, unexpected tIDENTIFIER, expecting keyword_end
   ...   fail ArgumentError, 'invalid value for "foo", must be one...
   ...                        ^~~~~~~
   /tmp/gem/lib/openapi_client/api/default_api.rb:38: syntax error, unexpected ',', expecting &. or :: or '[' or '.'
   ...rror, 'invalid value for "foo", must be one of ''
   ...                              ^
   /tmp/gem/lib/openapi_client/api/default_api.rb:65: Invalid return in class/module body
         return data, status_code, headers
         ^~~~~~
   /tmp/gem/lib/openapi_client/api/default_api.rb:111: syntax error, unexpected keyword_end, expecting end-of-input

Related issues/PRs

#2069 (closed)

Suggest a fix

(It is the same as #2069 (closed))

escapeText of RubyClientCodegen seems to escape for double-quote string literals only. However, the corresponding template uses a single quote string. I think it is difficult for the generator to determine whether the expansion destination is a single-quote string or a double-quote string. Instead, I think that it is better to unify it with a double-quote string in the template.