OpenAPITools/openapi-generator

Rust codegen creates incorrectly escaped parameter names

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#1222 opened on Oct 11, 2018

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Client: RustHacktoberfestIssue: BugServer: Rusthelp wanted

Description

Description

Generating Rust APIs for Kubernetes or any other API using parameters names which match keywords generates invalid rust since the escaped parameters names are invalid.

The swagger file contains "continue" as a parameter. This gets escaped by the codegen to “_continue”. Unfortunately this fails to compile when used in a format macro:

error: invalid format string: invalid argument name `_continue`
     --> kubernetes/src/client/mod.rs:21864:99
      |
21864 |         let query__continue = param__continue.map_or_else(String::new, |query| format!("continue={_continue}&", _continue=query.to_string()));
      |                                                                                                   ^^^^^^^^^ invalid argument name in format string
      |
      = note: argument names cannot start with an underscore
OpenAPI declaration file content or url

https://raw.githubusercontent.com/kubernetes/kubernetes/release-1.11/api/openapi-spec/swagger.json https://raw.githubusercontent.com/kubernetes/kubernetes/master/api/swagger-spec/v1.json

Suggest a fix/enhancement

Could position, rather than parameter names, be used in the format string?

Contributor guide

Tech stack
rustjava
Domain
backendapitooling
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Familiarity with Rust string formattingUnderstanding of code generation patterns
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
20
Research direction
The issue is in the Rust codegen module of openapi generator. Look at how parameter names are escaped (e.g., underscores prepended to keywords) and then used in format strings. The format macro fails because argument names cannot start with ' '. As suggested, consider using positional arguments like `format!("continue={0}", query)` or change the escaping logic to avoid leading underscores. Check the file `modules/openapi generator/src/main/resources/rust/libraries/reqwest/api.mustache` or similar templates.