[BUG][RUBY-NEXTGEN] Invalid method names from path segments such as {id}!preview, {id}:archive or export.csv

[wiebren]

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?

Description

ruby-nextgen names an operation's method after the literal path segments (RubyApiRouting.deriveAction, step b), unless the operationId starts with the group name (thingsPreview → preview, step a). Any other operationId is ignored. Step (b) runs each literal segment through underscore() but doesn't sanitize it, so a segment that is valid in a URL but not in a Ruby identifier becomes an invalid def:

path	method
/things/{id}!preview	def {id}!preview(id:)
/things/{id}:archive	def {id}:archive(id:)
/things/{id}/export.csv	def export/csv(id:) (underscore turns . into /)
/things/{id}/re-index	def re_index(id:) (fine)

A segment such as {id}!preview is not treated as a parameter because it doesn't end in }, so the placeholder ends up in the name. A single such path makes the whole api file fail to parse, so every operation in that group is lost.

openapi-generator version

master, 7.26.0-SNAPSHOT, 05b61f34d7fb0199330e1d6c57e6159f72427837

OpenAPI declaration file content or url

openapi: 3.0.3
info:
  title: names
  version: 1.0.0
paths:
  /things:
    get:
      operationId: listThings
      responses:
        '200':
          description: OK
  /things/{id}!preview:
    get:
      operationId: previewThing
      parameters:
        - $ref: '#/components/parameters/id'
      responses:
        '200':
          description: OK
  /things/{id}/re-index:
    post:
      operationId: reindexThing
      parameters:
        - $ref: '#/components/parameters/id'
      responses:
        '204':
          description: No content
  /things/{id}/export.csv:
    get:
      operationId: exportThing
      parameters:
        - $ref: '#/components/parameters/id'
      responses:
        '200':
          description: OK
  /things/{id}:archive:
    post:
      operationId: archiveThing
      parameters:
        - $ref: '#/components/parameters/id'
      responses:
        '204':
          description: No content
components:
  parameters:
    id:
      name: id
      in: path
      required: true
      schema:
        type: string

Generation Details

java -jar openapi-generator-cli.jar generate -g ruby-nextgen -i spec.yaml -o out \
  --additional-properties=gemName=petstore,moduleName=Petstore

Generation succeeds without warnings. Generated lib/petstore/api/things.rb (method heads):

      def export/csv(id:)
      def list
      def re_index(id:)
      def {id}!preview(id:)
      def {id}:archive(id:)

Steps to reproduce

ruby -c out/lib/petstore/api/things.rb

Actual (ruby 3.3):

out/lib/petstore/api/things.rb:10: syntax error, unexpected '/', expecting ';' or '\n' (SyntaxError)
      def export/csv(id:)
out/lib/petstore/api/things.rb:43: syntax error, unexpected {
      def {id}!preview(id:)
out/lib/petstore/api/things.rb:55: syntax error, unexpected {
      def {id}:archive(id:)

Petstore::Client.new(base_url: 'http://localhost').things fails with the same SyntaxError when Zeitwerk loads the file.

Expected: valid method names, e.g. preview, archive, export_csv, re_index.

Related issues/PRs

None found.

Suggest a fix

In step (b), remove {param} placeholders and replace non-identifier characters before underscore():

--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/rubynextgen/RubyApiRouting.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/rubynextgen/RubyApiRouting.java
@@ -154,8 +154,11 @@ public final class RubyApiRouting {
         if (actionStart < lits.size()) {
             StringBuilder sb = new StringBuilder();
             for (int i = actionStart; i < lits.size(); i++) {
+                String lit = lits.get(i).replaceAll("\\{[^}]*\\}", "").replaceAll("[^A-Za-z0-9_]+", "_");
+                lit = lit.replaceAll("^_+|_+$", "");
+                if (lit.isEmpty()) continue;
                 if (sb.length() > 0) sb.append("_");
-                sb.append(underscore(lits.get(i)));
+                sb.append(underscore(lit));
             }
             return sb.toString();
         }

With this change the methods become archive, export_csv, list, preview and re_index, and the file loads. CrystalApiRouting has the same loop (not checked against the crystal output).

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