[BUG][RUST_SERVER] Integration test fails because of clippy lint

[myz-dev]

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?

Expected output

Integration test passes

Actual output

Integration test fails

• [ ] [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

The integration test for the rust-server generator fails. The reason for this is that the Rust linter clippy is configured to run as the last step of the test, but a lint is given out for the generated code. Here is the definition within samples/server/petstore/rust-server/pom.xml:

<execution>
    <id>clippy</id>
    <phase>integration-test</phase>
    <goals>
        <goal>exec</goal>
    </goals>
    <configuration>
        <executable>cargo</executable>
        <arguments>
            <argument>clippy</argument>
        </arguments>
    </configuration>
</execution>

Running the integration test produces output like this:

error: in a `match` scrutinee, avoid complex blocks or closures with blocks; instead, move the block or closure higher and bind it with a `let`
    --> output/petstore-with-fake-endpoints-models-for-testing/src/server/mod.rs:2930:91
     |
2930 |   ...                   match serde_ignored::deserialize(deserializer, |path| {
     |  _____________________________________________________________________________^
2931 | | ...                           warn!("Ignoring unknown field in body: {}", path);
2932 | | ...                           unused_elements.push(path.to_string());
2933 | | ...                   }) {
     | |_______________________^
     |
     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#blocks_in_conditions

error: could not compile `petstore-with-fake-endpoints-models-for-testing` (lib) due to 16 previous errors
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  43.002 s
[INFO] Finished at: 2024-05-05T15:08:26+02:00
[INFO] ------------------------------------------------------------------------
[INFO] 4 goals, 4 executed
[INFO] Cleaning up the local build cache...
[INFO] Deleted 0 unused files from the local build cache in 0.025s
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.2.1:exec (clippy) on project RustServerTests: Command execution failed.: Process exited with an error: 101 (Exit value: 101) -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

openapi-generator version 7.6.0-SNAPSHOT

OpenAPI declaration file content or url

This happens for different samples, the most simple one is modules/openapi-generator/src/test/resources/3_0/rust-server/no-example-v3.yaml

Generation Details + Steps to reproduce

./bin/generate-samples.sh ./bin/configs/rust-server-* mvn integration-test -f samples/server/petstore/rust-server/pom.xml

Suggest a fix

I see two ways to fix this. Depending on the way the project wants to move forwards I can provide the fix

1. Fix the code generation to respect the clippy lint. This would mean the code within modules/openapi-generator/src/main/resources/rust-server/server-operation.mustache should change from

   let mut unused_elements = Vec::new();
   match serde_ignored::deserialize(deserializer, |path| {
         warn!("Ignoring unknown field in body: {}", path);
         unused_elements.push(path.to_string());
   }) {...}
   

   to something like:

   let record_unused =  |path: serde_ignored::Path<'_>| {
       warn!("Ignoring unknown field in body: {}", path);
       unused_elements.push(path.to_string());
       };
   match serde_ignored::deserialize(deserializer, record_unused)  {...}
   

2. We could also just configure clippy to not output an error on this specific lint

[wing328]

Fix the code generation to respect the clippy lint.

@myz-dev I prefer this