[BUG] Regular expressions which have forward slash generate invalid ruby code.

[mkanoor]

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?

• [X ] Have you search for related issues/PRs?

• What's the actual output vs expected output?

• [Optional] Bounty to sponsor the fix (example)

Description

In Regular expression the forward slash only needs to be escaped if its inside the /pattern/ format, if the pattern is a string and fed into Regexp.new it doesn't need to be escaped with a backslash.

openapi-generator/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java

Line 4825 in de2753d

if (!pattern.matches("^/.*")) {

This code only checks if the string starts with a leading slash and assumes it's the /pattern/ format. The pattern can be a string and it could include both the leading and trailing slash e.g /root/.
Since Openapi regex pattern supports both the string pattern and the /pattern/ format its ambiguous what the code should generate.
For the pattern '/ax$|/bx$' the ruby code generated is Regexp.new(/ax$|/bx$) which fails with a syntax error
SyntaxError ((irb):20: unknown regexp option - b)
(irb):20: `$)' is not allowed as a global variable name
(irb):20: syntax error, unexpected end-of-input, expecting ')'
Regexp.new(/ax$|/bx$)

Can you please clarify if this a bug or that openapi regexes need to be always in the /pattern/ format.

openapi-generator version

4.2.2 also tried with master

OpenAPI declaration file content or url

https://gist.github.com/mkanoor/802eb64217e04e4e7b5fc12ac4ebf8c5

Command line used for generation

openapi-generator generate -i /tmp/test_regex.yaml -g ruby -o /tmp

Ruby

Steps to reproduce

openapi-generator generate -i /tmp/test_regex.yaml -g ruby -o /tmp

Related issues/PRs

#1392

Suggest a fix

Checking if there is a leading slash and a trailing slash before deciding if this is a /pattern/ format versus a string. That works as long as the regexp is not looking for a leading and trailing slash.

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[ivgiuliani]

Just bumped into this issue. I think this is the same problem as #1517 but for Ruby, however because Python/Ruby both use perl-flavored regexes, I imagine the fix is likely going to be very similar to what was done in #1539 (I have a test PR that I will try to clean up now that backports the python fix to the ruby code generator and it seems to work).