[Kotlin Server] Update Ktor to the next major version 3

[Stexxe]

• Update the Ktor version in the Kotlin Server template to 3.0.2.
• Fix compilation errors of the generated code.

technical committee: @stefankoppier

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[wing328]

@Stexxe thanks for the PR

can you please review the build failure when you've time?

[Stexxe]

@wing328, all the issues are fixed now.

[wing328]

@Stexxe all tests passed.

If no further feedback from anyone, I'll merge it over the weekend.

cc @dr4ke616 (2018/08) @karismann (2019/03) @Zomzog (2019/04) @andrewemery (2019/10) @4brunu (2019/11) @yutaka0m (2020/03) @stefankoppier (2022/06) @e5l (2024/10)

[e5l]

lgtm!

[wing328]

I tested with

 java -jar modules/openapi-generator-cli/target/openapi-generator-cli.jar generate -g kotlin-server -i modules/openapi-generator/src/test/resources/3_0/petstore.yaml -o /tmp/kotlin-server23 --additional-properties enableKotlinSerialization=false

but didn't see any difference in the output (compared with not setting enableKotlinSerialization and setting enableKotlinSerialization to true)

how can I test the option?

[Stexxe]

I tested with

 java -jar modules/openapi-generator-cli/target/openapi-generator-cli.jar generate -g kotlin-server -i modules/openapi-generator/src/test/resources/3_0/petstore.yaml -o /tmp/kotlin-server23 --additional-properties enableKotlinSerialization=false

but didn't see any difference in the output (compared with not setting enableKotlinSerialization and setting enableKotlinSerialization to true)

how can I test the option?

Can you please help me figure out why the additionalProperties.containsKey(Constants.KOTLIN_SERIALIZATION) call returns false when the enableKotlinSerialization passed as an additional property?

[wing328]

I'll take a look tomorrow and push a fix if possible.

Thanks again for filing the PR to start with

[Stexxe]

I've removed this property altogether. Please take a look.

[wing328]

FYI. I added ktor2 via 24ddb33 (should have filed a PR)

Will merge this PR tomorrow or this weekend so that users will get ktor (3.x) by default.

[wing328]

FYI. Merged #20327 with some minor fixes to ensure ktor2 produces the same output as before.