fix(NestJS): use correct typing for default headers

[bilalshaikh42]

closes #10615

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@TiFu @taxpon @sebastianhaas @kenisteward @Vrolijkx @macjohnny @topce @akehir @petejohansonxo @amakhrov

[amakhrov]

Thanks for your contribution!
The fix looks good.

I noticed that later in the service class there is a bug related to defaultHeaders:

let headers = this.defaultHeaders;
...
if ({{paramName}}) {
  headers['{{baseName}}'] = {{paramName}}.join(COLLECTION_FORMATS['{{collectionFormat}}']);
}     

This mutates defaultHeaders, affecting all future calls (even to different endpoints).

I assume you rely on the typescript-nestjs generator in your project, so you might want to address this issue as well (doesn't have to be in this PR though :) )

[bilalshaikh42]

Thanks for your contribution! The fix looks good.

I noticed that later in the service class there is a bug related to defaultHeaders:

let headers = this.defaultHeaders;
...
if ({{paramName}}) {
  headers['{{baseName}}'] = {{paramName}}.join(COLLECTION_FORMATS['{{collectionFormat}}']);
}     

This mutates defaultHeaders, affecting all future calls (even to different endpoints).

I assume you rely on the typescript-nestjs generator in your project, so you might want to address this issue as well (doesn't have to be in this PR though :) )

Sure, I would be interested in getting that as well. I have a few other changes to be made as well, to address updates in NestJS v8, but am not sure how to maintain backwards compatibility. Is there a set procedure for doing so?

As an example, one specific change I am thinking of is changing the import of HttpService from @nestjs/common to @nestjs/axios but that would break support for earlier versions.

[amakhrov]

As for breaking changes - if there is a good reason for that (like in your case, where httpservice in nestjs/common is officially deprecated), you still create a PR, and it can target the next major release of openapi-generator.

Alternatively, you can add a config option to the generator, e.g. nestjsVersion. So that if it's 8 or below the generator produces the code as it is now, but if it's 9 or higher, you generate imports from nestjs/axios. This approach is used in typescript-angular generator, allowing to seamlessly support apps that are stuck on older framework versions for whatever reason

[macjohnny]

@bilalshaikh42 thanks for your contribution. can you please update the samples?

[bilalshaikh42]

@macjohnny
I am running into the following error when running the command ./mvnw clean package. I am not that familiar with the java ecosystem, so not sure what could be doing wrong

with proper logic to escape unsafe characters
[ERROR] Tests run: 15, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 1.227 s <<< FAILURE! - in org.openapitools.codegen.DefaultGeneratorTest
[ERROR] org.openapitools.codegen.DefaultGeneratorTest.supportCustomTemplateEngine  Time elapsed: 0.302 s  <<< FAILURE!
java.lang.RuntimeException: Could not generate api file for 'Ping'
        at org.openapitools.codegen.DefaultGeneratorTest.supportCustomTemplateEngine(DefaultGeneratorTest.java:311)
Caused by: com.github.jknack.handlebars.HandlebarsException:
api.hbs:48:83: java.lang.reflect.InaccessibleObjectException: Unable to make field transient java.util.HashMap$Node[] java.util.HashMap.table accessible: module java.base does not "opens java.util" to unnamed module @76329302
    api.hbs:48:83
        at org.openapitools.codegen.DefaultGeneratorTest.supportCustomTemplateEngine(DefaultGeneratorTest.java:311)
Caused by: java.lang.reflect.InaccessibleObjectException: Unable to make field transient java.util.HashMap$Node[] java.util.HashMap.table accessible: module java.base does not "opens java.util" to unnamed module @76329302
        at org.openapitools.codegen.DefaultGeneratorTest.supportCustomTemplateEngine(DefaultGeneratorTest.java:311)

[main] INFO com.tngtech.archunit.core.PluginLoader - Detected Java version 16.0.2
[INFO] Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 4.074 s - in org.openapitools.codegen.ArchUnitRulesTest
[INFO]
[INFO] Results:
[INFO]
[ERROR] Failures:
[ERROR]   DefaultGeneratorTest.supportCustomTemplateEngine:311 » Runtime Could not gener...
[ERROR]   StringHelpersTest.startsWithSectionalTest:47->evaluate:28 » Handlebars inline@...
[ERROR]   StringHelpersTest.startsWithTest:61->evaluate:28 » Handlebars inline@43bd77be:...
[ERROR]   StringHelpersTest.startsWithYesOverrideTest:81->evaluate:28 » Handlebars inlin...
[INFO]
[ERROR] Tests run: 1550, Failures: 4, Errors: 0, Skipped: 0

[bilalshaikh42]

Though it seems the next few steps worked fine, so I pushed those. Let me know if there is anything else I need to do!