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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)?
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Description

When generating typescript-angular api's from a spec that uses externe type mappings inside a response body, the generator is stuck in an infinite loop when trying to 'unalias' the schema for the external type.

Exception in thread "main" java.lang.StackOverflowError at java.util.regex.Pattern.error(Pattern.java:1969) at java.util.regex.Pattern.<init>(Pattern.java:1354) at java.util.regex.Pattern.compile(Pattern.java:1054) at java.lang.String.replace(String.java:2239) at org.openapitools.codegen.utils.ModelUtils.getSimpleRef(ModelUtils.java:406) at org.openapitools.codegen.utils.ModelUtils.unaliasSchema(ModelUtils.java:1208) at org.openapitools.codegen.utils.ModelUtils.unaliasSchema(ModelUtils.java:1256) at org.openapitools.codegen.utils.ModelUtils.unaliasSchema(ModelUtils.java:1256) at org.openapitools.codegen.utils.ModelUtils.unaliasSchema(ModelUtils.java:1256)

openapi-generator version

6.0.1

OpenAPI declaration file content or url

openapi: 3.0.1
info:
  title: OpenAPI definition
  version: v0
paths:
  "/api/external-resources":
    get:
      operationId: getExternalResources
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                type: array
                items:
                  "$ref": "#/components/schemas/ExternalResource"
components:
  schemas:
    ExternalResource:
      "$ref": "#/components/schemas/ExternalResource"

Generation Details

<plugin>
	<groupId>org.openapitools</groupId>
	<artifactId>openapi-generator-maven-plugin</artifactId>
	<version>6.0.1</version>
	<executions>
		<execution>
			<phase>generate-sources</phase>
			<goals>
				<goal>generate</goal>
			</goals>
			<configuration>
				<inputSpec>openapi.yaml</inputSpec>
				<generatorName>typescript-angular</generatorName>
				<schemaMappings>ExternalResource</schemaMappings>
				<importMappings>ExternalResource=@external/resource</importMappings>
			</configuration>
		</execution>
	</executions>
</plugin>

Steps to reproduce

Generate typescript based on above spec and provided maven plugin configuration.

Related issues/PRs

Suggest a fix

Passing the schemaMapping in AbstractTypeScriptClientCodegen to the unaliasSchema method on lines 433 and 437 fixes the issue.

ModelUtils.unaliasSchema(this.openAPI, items, schemaMapping)