[BUG][RUST] New AbstractRustCodegen.java not handling period-delimited model names well.

Bug Report Checklist

[X] Have you provided a full/minimal spec to reproduce the issue?
[X] Have you validated the input using an OpenAPI validator (example)?
[X] Have you tested with the latest master to confirm the issue still exists?
[X] Have you searched for related issues/PRs?
[X] What's the actual output vs expected output?
[ ] [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

I am working with the Microsoft Graph API specification (although I used yq -o=json eval openapi.yaml > openapi.json to convert to a JSON spec first, since there are too many Yaml code points for swagger-parser in v6.5.0 of openapi-generator). It has models named in the following format:

microsoft.graph.user
microsoft.graph.authenticationMethod
microsoft.graph.fido2AuthenticationMethod

etc. The Rust client generator is outputting the following warnings:

[main] WARN o.o.c.languages.AbstractRustCodegen - MicrosoftGraphFido2AuthenticationMethod cannot be used as a model name. Renamed to MicrosoftPeriodGraphPeriodFido2AuthenticationMethod

[main] WARN o.o.c.languages.AbstractRustCodegen - microsoft/graph/fido2_authentication_method cannot be used as a model file name. Renamed to microsoft_period_graph_period_fido2_authentication_method

This output is perplexing, as MicrosoftGraphFido2AuthenticationMethod post-sanitizing is completely legitimate for Rust, but it still performs another pass and adds Period in placements where . is in the original model name.

Likewise, the module file pathing microsoft/graph/fido2_authentication_method would be perfectly legitimate (assuming proper supporting mod.rs files were generated along the path) as a module path and file name. Or if not that microsoft_graph_fido2_authentication_method would be perfectly good as well, without the added _period separator in the module path name.

I realize these may be two separate issues, but since Period and _period are likely rooted with the same failing to handle . delimited model names, I bet they can be solved together.

openapi-generator version

6.5.0

OpenAPI declaration file content or url

https://raw.githubusercontent.com/microsoftgraph/msgraph-metadata/master/openapi/v1.0/openapi.yaml

converted to json with:

yq -o=json eval openapi.yaml > openapi.json

Generation Details

openapi-generator generate -g rust \
  -i openapi.json \
  -o ms-graph-rust \
  --additional-properties=useSingleRequestParameter=true \
  --skip-validate-spec

Steps to reproduce

Download the openapi.yaml spec.
Convert to openapi.json spec.
Run the above command, see all of the WARN output.

Suggest a fix

I briefly reviewed the AbstractRustCodegen class and how its calling down into DefaultCodegen for various name sanitizing and character replacement, but didn't dig very deep. I feel like the owner of AbstractRustCodegen will know of a good way to handle this issue immediately after reading this description.

OpenAPITools / openapi-generator