[BUG] The generator generates invalid value for the "example" field

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• What's the version of OpenAPI Generator used?
• Have you search for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Bounty to sponsor the fix (example)

Description

Sometimes, the generated value for "example" fields are wrong.

openapi-generator version

4.2.3

OpenAPI declaration file content or url

openapi: "3.0.0"

info:
  title: Test
  version: 1.0.0

paths:
  /test:
    post:
      summary: A simple endpoint.
      description: A more detailed explanation of our simple endpoint.
      parameters:
      - in: header
        name: X-Custom
        required: true
        schema:
          $ref: '#/components/schemas/Custom'
      responses:
        '200':
          description: OK

components:
  schemas:
    Custom:
      description: Some description.
      type: string
      format: fubar
      pattern: '^(foo|bar|baz)+$'
      example: foofoobazbarfoo

Command line used for generation

openapi-generator generate -i sample.yaml -g asciidoc -v

Steps to reproduce

1. Save the given Open API spec in a file named sample.yaml
2. Run openapi-generator generate -i sample.yaml -g asciidoc -v
3. The example field should have the value foofoobazbarfoo but it has xCustom_example:

{
  "licenseUrl" : "http://apache.org/licenses/LICENSE-2.0.html",
  "appVersion" : "1.0.0",
  "generatedYear" : "2020",
  "generatorClass" : "org.openapitools.codegen.languages.AsciidocDocumentationCodegen",
  "openAPI" : {
    "openapi" : "3.0.0",
    "info" : {
      "title" : "Test",
      "version" : "1.0.0"
    },
    "servers" : [ {
      "url" : "/"
    } ],
    "paths" : {
      "/test" : {
        "post" : {
          "summary" : "A simple endpoint.",
          "description" : "A more detailed explanation of our simple endpoint.",
          "parameters" : [ {
            "name" : "X-Custom",
            "in" : "header",
            "required" : true,
            "style" : "simple",
            "explode" : false,
            "schema" : {
              "$ref" : "#/components/schemas/Custom"
            }
          } ],
          "responses" : {
            "200" : {
              "description" : "OK"
            }
          }
        }
      }
    },
    "components" : {
      "schemas" : {
        "Custom" : {
          "pattern" : "^(foo|bar|baz)+$",
          "type" : "string",
          "description" : "Some description.",
          "format" : "fubar",
          "example" : "foofoobazbarfoo"
        }
      }
    }
  },
  "scheme" : "http",
  "modelPackage" : "",
  "groupId" : "org.openapitools",
  "gitHost" : "github.com",
  "licenseInfo" : "All rights reserved",
  "invokerPackage" : "org.openapitools.client",
  "apiFolder" : "",
  "generateApis" : true,
  "generateModelDocs" : true,
  "generateModelTests" : true,
  "basePathWithoutHost" : "",
  "generateApiTests" : true,
  "lambda" : {
    "lowercase" : { },
    "uppercase" : { },
    "titlecase" : { },
    "camelcase" : { },
    "indented" : { },
    "indented_8" : { },
    "indented_12" : { },
    "indented_16" : { }
  },
  "generateModels" : true,
  "servers" : [ {
    "url" : "/",
    "variables" : [ ]
  } ],
  "infoUrl" : "https://openapi-generator.tech",
  "inputSpec" : "sample.yaml",
  "host" : "localhost",
  "artifactId" : "openapi-client",
  "hideGenerationTimestamp" : true,
  "snippetlink" : { },
  "unescapedAppDescription" : "No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)",
  "models" : [ ],
  "artifactVersion" : "1.0.0",
  "appName" : "Test",
  "snippetinclude" : { },
  "appDescription" : "No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)",
  "contextPath" : "",
  "generateApiDocs" : true,
  "generatorVersion" : "4.2.3",
  "releaseNote" : "Minor update",
  "version" : "1.0.0",
  "apiInfo" : {
    "apis" : [ {
      "appVersion" : "1.0.0",
      "generatorClass" : "org.openapitools.codegen.languages.AsciidocDocumentationCodegen",
      "sortParamsByRequiredFlag" : true,
      "groupId" : "org.openapitools",
      "invokerPackage" : "org.openapitools.client",
      "classVarName" : "default",
      "generateModelDocs" : true,
      "hasImport" : true,
      "generateModelTests" : true,
      "strictSpecBehavior" : true,
      "generateApiTests" : true,
      "classFilename" : "DefaultApi",
      "lambda" : {
        "lowercase" : { },
        "uppercase" : { },
        "titlecase" : { },
        "camelcase" : { },
        "indented" : { },
        "indented_8" : { },
        "indented_12" : { },
        "indented_16" : { }
      },
      "generateModels" : true,
      "infoUrl" : "https://openapi-generator.tech",
      "inputSpec" : "sample.yaml",
      "baseName" : "Default",
      "snippetlink" : { },
      "package" : "",
      "imports" : [ {
        "import" : "string",
        "classname" : "string"
      } ],
      "snippetinclude" : { },
      "contextPath" : "",
      "appDescription" : "No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)",
      "releaseNote" : "Minor update",
      "version" : "1.0.0",
      "specinclude" : { },
      "headerAttributes" : true,
      "importPath" : ".Default",
      "licenseUrl" : "http://apache.org/licenses/LICENSE-2.0.html",
      "generatedYear" : "2020",
      "modelPackage" : "",
      "gitHost" : "github.com",
      "licenseInfo" : "All rights reserved",
      "hasModel" : false,
      "generateApis" : true,
      "basePathWithoutHost" : "",
      "operations" : {
        "classname" : "DefaultApi",
        "operation" : [ {
          "responseHeaders" : [ ],
          "hasAuthMethods" : false,
          "hasConsumes" : false,
          "hasProduces" : false,
          "hasParams" : true,
          "hasOptionalParams" : false,
          "hasRequiredParams" : true,
          "returnTypeIsPrimitive" : false,
          "returnSimpleType" : false,
          "subresourceOperation" : false,
          "isMapContainer" : false,
          "isListContainer" : false,
          "isMultipart" : false,
          "hasMore" : false,
          "isResponseBinary" : false,
          "isResponseFile" : false,
          "hasReference" : false,
          "isRestfulIndex" : false,
          "isRestfulShow" : false,
          "isRestfulCreate" : false,
          "isRestfulUpdate" : false,
          "isRestfulDestroy" : false,
          "isRestful" : false,
          "isDeprecated" : false,
          "isCallbackRequest" : false,
          "path" : "/test",
          "operationId" : "testPost",
          "httpMethod" : "POST",
          "summary" : "A simple endpoint.",
          "unescapedNotes" : "A more detailed explanation of our simple endpoint.",
          "notes" : "A more detailed explanation of our simple endpoint.",
          "baseName" : "Default",
          "servers" : [ ],
          "allParams" : [ {
            "isFormParam" : false,
            "isQueryParam" : false,
            "isPathParam" : false,
            "isHeaderParam" : true,
            "isCookieParam" : false,
            "isBodyParam" : false,
            "hasMore" : false,
            "isContainer" : false,
            "secondaryParam" : false,
            "isCollectionFormatMulti" : false,
            "isPrimitiveType" : true,
            "isModel" : false,
            "isExplode" : false,
            "baseName" : "X-Custom",
            "paramName" : "xCustom",
            "dataType" : "String",
            "dataFormat" : "fubar",
            "defaultValue" : "null",
            "style" : "simple",
            "example" : "xCustom_example",
            "jsonSchema" : "{\n  \"name\" : \"X-Custom\",\n  \"in\" : \"header\",\n  \"required\" : true,\n  \"style\" : \"simple\",\n  \"explode\" : false,\n  \"schema\" : {\n    \"$ref\" : \"#/components/schemas/Custom\"\n  }\n}",
            "isString" : true,
            "isNumeric" : false,
            "isInteger" : false,
            "isLong" : false,
            "isNumber" : false,
            "isFloat" : false,
            "isDouble" : false,
            "isByteArray" : false,
            "isBinary" : false,
            "isBoolean" : false,
            "isDate" : false,
            "isDateTime" : false,
            "isUuid" : false,
            "isUri" : false,
            "isEmail" : false,
            "isFreeFormObject" : false,
            "isListContainer" : false,
            "isMapContainer" : false,
            "isFile" : false,
            "isEnum" : false,
            "vendorExtensions" : { },
            "hasValidation" : true,
            "isNullable" : false,
            "required" : true,
            "exclusiveMaximum" : false,
            "exclusiveMinimum" : false,
            "pattern" : "/^(foo|bar|baz)+$/",
            "uniqueItems" : false
          } ],
          "bodyParams" : [ ],
          "pathParams" : [ ],
          "queryParams" : [ ],
          "headerParams" : [ {
            "isFormParam" : false,
            "isQueryParam" : false,
            "isPathParam" : false,
            "isHeaderParam" : true,
            "isCookieParam" : false,
            "isBodyParam" : false,
            "hasMore" : false,
            "isContainer" : false,
            "secondaryParam" : false,
            "isCollectionFormatMulti" : false,
            "isPrimitiveType" : true,
            "isModel" : false,
            "isExplode" : false,
            "baseName" : "X-Custom",
            "paramName" : "xCustom",
            "dataType" : "String",
            "dataFormat" : "fubar",
            "defaultValue" : "null",
            "style" : "simple",
            "example" : "xCustom_example",
            "jsonSchema" : "{\n  \"name\" : \"X-Custom\",\n  \"in\" : \"header\",\n  \"required\" : true,\n  \"style\" : \"simple\",\n  \"explode\" : false,\n  \"schema\" : {\n    \"$ref\" : \"#/components/schemas/Custom\"\n  }\n}",
            "isString" : true,
            "isNumeric" : false,
            "isInteger" : false,
            "isLong" : false,
            "isNumber" : false,
            "isFloat" : false,
            "isDouble" : false,
            "isByteArray" : false,
            "isBinary" : false,
            "isBoolean" : false,
            "isDate" : false,
            "isDateTime" : false,
            "isUuid" : false,
            "isUri" : false,
            "isEmail" : false,
            "isFreeFormObject" : false,
            "isListContainer" : false,
            "isMapContainer" : false,
            "isFile" : false,
            "isEnum" : false,
            "vendorExtensions" : { },
            "hasValidation" : true,
            "isNullable" : false,
            "required" : true,
            "exclusiveMaximum" : false,
            "exclusiveMinimum" : false,
            "pattern" : "/^(foo|bar|baz)+$/",
            "uniqueItems" : false
          } ],
          "formParams" : [ ],
          "cookieParams" : [ ],
          "requiredParams" : [ {
            "isFormParam" : false,
            "isQueryParam" : false,
            "isPathParam" : false,
            "isHeaderParam" : true,
            "isCookieParam" : false,
            "isBodyParam" : false,
            "hasMore" : false,
            "isContainer" : false,
            "secondaryParam" : false,
            "isCollectionFormatMulti" : false,
            "isPrimitiveType" : true,
            "isModel" : false,
            "isExplode" : false,
            "baseName" : "X-Custom",
            "paramName" : "xCustom",
            "dataType" : "String",
            "dataFormat" : "fubar",
            "defaultValue" : "null",
            "style" : "simple",
            "example" : "xCustom_example",
            "jsonSchema" : "{\n  \"name\" : \"X-Custom\",\n  \"in\" : \"header\",\n  \"required\" : true,\n  \"style\" : \"simple\",\n  \"explode\" : false,\n  \"schema\" : {\n    \"$ref\" : \"#/components/schemas/Custom\"\n  }\n}",
            "isString" : true,
            "isNumeric" : false,
            "isInteger" : false,
            "isLong" : false,
            "isNumber" : false,
            "isFloat" : false,
            "isDouble" : false,
            "isByteArray" : false,
            "isBinary" : false,
            "isBoolean" : false,
            "isDate" : false,
            "isDateTime" : false,
            "isUuid" : false,
            "isUri" : false,
            "isEmail" : false,
            "isFreeFormObject" : false,
            "isListContainer" : false,
            "isMapContainer" : false,
            "isFile" : false,
            "isEnum" : false,
            "vendorExtensions" : { },
            "hasValidation" : true,
            "isNullable" : false,
            "required" : true,
            "exclusiveMaximum" : false,
            "exclusiveMinimum" : false,
            "pattern" : "/^(foo|bar|baz)+$/",
            "uniqueItems" : false
          } ],
          "optionalParams" : [ ],
          "tags" : [ {
            "name" : "default"
          } ],
          "responses" : [ {
            "headers" : [ ],
            "code" : "200",
            "message" : "OK",
            "hasMore" : false,
            "hasHeaders" : false,
            "isString" : false,
            "isNumeric" : false,
            "isInteger" : false,
            "isLong" : false,
            "isNumber" : false,
            "isFloat" : false,
            "isDouble" : false,
            "isByteArray" : false,
            "isBoolean" : false,
            "isDate" : false,
            "isDateTime" : false,
            "isUuid" : false,
            "isEmail" : false,
            "isModel" : false,
            "isFreeFormObject" : false,
            "isDefault" : true,
            "simpleType" : true,
            "primitiveType" : true,
            "isMapContainer" : false,
            "isListContainer" : false,
            "isBinary" : false,
            "isFile" : false,
            "jsonSchema" : "{\n  \"description\" : \"OK\"\n}",
            "vendorExtensions" : { },
            "uniqueItems" : false,
            "exclusiveMinimum" : false,
            "exclusiveMaximum" : false,
            "wildcard" : false
          } ],
          "callbacks" : [ ],
          "imports" : [ "string" ],
          "vendorExtensions" : { },
          "nickname" : "testPost",
          "operationIdLowerCase" : "testpost",
          "operationIdCamelCase" : "TestPost",
          "operationIdSnakeCase" : "test_post",
          "hasExamples" : false,
          "hasFormParams" : false,
          "restfulShow" : false,
          "restfulIndex" : false,
          "restfulCreate" : false,
          "restfulUpdate" : false,
          "restfulDestroy" : false,
          "restful" : false,
          "hasBodyParam" : false,
          "hasPathParams" : false,
          "hasQueryParams" : false,
          "bodyAllowed" : true,
          "hasHeaderParams" : true,
          "hasCookieParams" : false,
          "hasResponseHeaders" : false
        } ],
        "pathPrefix" : "default"
      },
      "artifactId" : "openapi-client",
      "hideGenerationTimestamp" : true,
      "unescapedAppDescription" : "No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)",
      "artifactVersion" : "1.0.0",
      "appName" : "Test",
      "generateApiDocs" : true,
      "generatorVersion" : "4.2.3",
      "apiPackage" : "",
      "basePath" : "http://localhost",
      "classname" : "DefaultApi",
      "gitRepoId" : "GIT_REPO_ID",
      "generatedDate" : "2020-03-26T00:16:46.255299+11:00[Australia/Melbourne]",
      "infoEmail" : "team@openapitools.org",
      "appDescriptionWithNewLines" : "No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)",
      "gitUserId" : "GIT_USER_ID"
    } ]
  },
  "apiPackage" : "",
  "hasServers" : true,
  "basePath" : "http://localhost",
  "specinclude" : { },
  "gitRepoId" : "GIT_REPO_ID",
  "generatedDate" : "2020-03-26T00:16:46.255299+11:00[Australia/Melbourne]",
  "infoEmail" : "team@openapitools.org",
  "appDescriptionWithNewLines" : "No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)",
  "headerAttributes" : true,
  "gitUserId" : "GIT_USER_ID"
}

Related issues/PRs

Suggest a fix

Save the supplied OpenAPI declaration as sample.yaml and run the stated openapi-generator command with the asciidoc generator. Inspect the generated output and the AsciidocDocumentationCodegen entry point; done means the schema example value foofoobazbarfoo is retained instead of xCustom_example.