[BUG] Additional boolean values are not correctly mapped (typescript-angular, typescript-nestjs, ...)

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• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
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• What's the actual output vs expected output?
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Description

If I generate code with the CLI and use additional boolean properties, then not all properties are correctly mapped.

generate -g typescript-angular -i ... -o ... -p withInterfaces=false
generate -g typescript-nestjs -i ... -o ... -p withInterfaces=false

The boolean value are interpreted as basic 'string', therefore the mustache templating doesn't work.

Suggest a fix

Option 1: The additional properties are generator based, therefore the first intension would be to fix this conversation error there, e.g. by using the convertPropertyToBooleanAndWriteBack function.

if (additionalProperties.containsKey(WITH_INTERFACES)) {
convertPropertyToBooleanAndWriteBack(WITH_INTERFACES);
}

Option 2: I think a better solution would be to convert types based on the CliOption. The CliOption contains the option type, hence that can be used for conversation.

var cliOpts = config.cliOptions().stream().collect(Collectors.toMap(CliOption::getOpt, Function.identity()));
config.additionalProperties().entrySet().forEach(e -> {
var cliOption = Optional.ofNullable(cliOpts.get(e.getKey()));
if (cliOption.isPresent() && "boolean".equals(cliOption.get().getType())) {
config.additionalProperties().put(e.getKey(), Boolean.valueOf(e.getValue().toString()));
}
});

Option 3: An other basic fix could be to make the conversation happen at the CodegenConfigurationUtils:applyAdditionalProperty. At this point the value can be checked:

if ("true".equalsIgnoreCase(value) || "false".equalsIgnoreCase(value)) {
value = Boolean.valueOf(value);
}

openapi-generator version

7.7.0, master branch

OpenAPI declaration file content or url

Any declaration file or url can be used

Reproduce the issue with the typescript-angular and typescript-nestjs generators, then inspect CodegenConfigurationUtils.applyAdditionalProperty, CliOption, and convertPropertyToBooleanAndWriteBack. Determine where additional boolean values become strings and verify that boolean options remain booleans so the generated templates map them correctly.