[RUST-AXUM] Fix #18580: disableValidation does not create superfluous code

[myz-dev]

As described in #18580 the rust-axum generator has the useful option disableValidator. Until now when enabled it skipped calling the validation functions in the generated handler. But it would in any case create the validation logic. There is a bug that leads to invalid code being generated with some specifications. This PR does not (yet) fix the generated code, but it does make the disableValidator option not render any unnecessary code. Thereby working around the bug for now is possible by disabling the validation logic alltogether.

Changes:

• The validation mustache file is only rendered when disableValidator is falsy. server-mod.mustache

  ...
  {{^disableValidator}}
  {{>server-operation-validate}}
  {{/disableValidator}}
  ...

• An integration test adds a specification that creates buggy validation code and disables the validator, so that the code is not rendered and the test passes. Again: The bug itself is not fixed with this PR. A clean solution to this problem seems complicated.

PR checklist

• [x] Read the contribution guidelines.
• [x] Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
• [x] Run the following to build the project and update samples:

  ./mvnw clean package 
  ./bin/generate-samples.sh ./bin/configs/*.yaml
  ./bin/utils/export_docs_generators.sh
  

  (For Windows users, please run the script in Git BASH) Commit all changed files. This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master. These must match the expectations made by your contribution. You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/java*. IMPORTANT: Do NOT purge/delete any folders/files (e.g. tests) when regenerating the samples as manually written tests may be removed.
• [x] File the PR against the correct branch: master (upcoming 7.1.0 minor release - breaking changes with fallbacks), 8.0.x (breaking changes without fallbacks)
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[myz-dev]

The verify git status check fails:

UNCOMMITTED CHANGES ERROR
There are uncommitted changes in working tree after execution of 'bin/generate-samples.sh'

I do not understand why. Running these commands locally does not produce any new/changed files in my working directory:

./bin/generate-samples.sh ./bin/configs/*.yaml
./bin/utils/export_docs_generators.sh

[wing328]

thanks for the PR.

cc @linxGnu - the author of the generator

[linxGnu]

Thank you for the PR @myz-dev

[wing328]

@linxGnu when you've time, can you please PM me via Slack?

https://join.slack.com/t/openapi-generator/shared_invite/zt-12jxxd7p2-XUeQM~4pzsU9x~eGLQqX2g