Autoset constants (Required fields having single valid enum value) (#16761)

* Autoset constants (Required fields having single valid enum value) Python Implementation of #16547

* Fixing ``PythonClientCodegenTest.testHandleConstantParams`` for Windows platform.

modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenConstants.java

@@ -43,6 +43,8 @@ public class CodegenConstants {
     public static final String API_SUFFIX = "apiSuffix";
     public static final String API_SUFFIX_DESC = "suffix for api classes";
 
+    public static final String AUTOSET_CONSTANTS = "autosetConstants";
+
     public static final String MODEL_PACKAGE = "modelPackage";
     public static final String MODEL_PACKAGE_DESC = "package for generated models";
 

modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java

@@ -304,6 +304,9 @@ public class DefaultCodegen implements CodegenConfig {
 
     protected boolean addSuffixToDuplicateOperationNicknames = true;
 
+    // Whether to automatically hardcode params that are considered Constants by OpenAPI Spec
+    protected boolean autosetConstants = false;
+
     public boolean getAddSuffixToDuplicateOperationNicknames() {
         return addSuffixToDuplicateOperationNicknames;
     }
@@ -427,6 +430,10 @@ public class DefaultCodegen implements CodegenConfig {
             this.setEnumUnknownDefaultCase(Boolean.parseBoolean(additionalProperties
                     .get(CodegenConstants.ENUM_UNKNOWN_DEFAULT_CASE).toString()));
         }
+        if (additionalProperties.containsKey(CodegenConstants.AUTOSET_CONSTANTS)) {
+            this.setAutosetConstants(
+                    Boolean.parseBoolean(additionalProperties.get(CodegenConstants.AUTOSET_CONSTANTS).toString()));
+        }
     }
 
     /***
@@ -8282,4 +8289,47 @@ public class DefaultCodegen implements CodegenConfig {
             throw new IllegalArgumentException("Invalid schema type; type must be Boolean or Schema");
         }
     }
+
+    public void setAutosetConstants(boolean autosetConstants) {
+        this.autosetConstants = autosetConstants;
+    }
+
+    /**
+     * This method removes all constant Query, Header and Cookie Params from allParams and sets them as constantParams in the CodegenOperation.
+     * The definition of constant is single valued required enum params.
+     * The constantParams in the the generated code should be hardcoded to the constantValue if autosetConstants feature is enabled.
+     *
+     * @param operation - operation to be processed
+     */
+    protected void handleConstantParams(CodegenOperation operation) {
+        if (!autosetConstants || operation.allParams.isEmpty()) {            
+            return;
+        }
+        final ArrayList<CodegenParameter> copy = new ArrayList<>(operation.allParams);
+        // Remove all params from Params, Non constant params will be added back later.
+        operation.allParams.clear();
+
+        // Finds all constant params, removes them from allParams and adds them to constant params.
+        // Also, adds back non constant params to allParams.
+        for (CodegenParameter p : copy) {
+            if (p.isEnum && p.required && p._enum != null && p._enum.size() == 1) {
+                // Add to constantParams for use in the code generation templates. 
+                operation.constantParams.add(p);
+                if(p.isQueryParam) {
+                    operation.queryParams.removeIf(param -> param.baseName.equals(p.baseName));
+                }
+                if(p.isHeaderParam) {
+                    operation.headerParams.removeIf(param -> param.baseName.equals(p.baseName));
+                }
+                if(p.isCookieParam) {
+                    operation.cookieParams.removeIf(param -> param.baseName.equals(p.baseName));
+                }
+                LOGGER.info("Update operation [{}]. Remove parameter [{}] because it can only have a fixed value of [{}]", operation.operationId, p.baseName, p._enum.get(0));
+            } else {
+                // Add back to allParams as the param is not a constant.
+                operation.allParams.add(p);
+            }
+        }
+        operation.hasParams = !operation.allParams.isEmpty();
+    }
 }

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java

@@ -82,7 +82,6 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
     public static final String TEST_OUTPUT = "testOutput";
     public static final String IMPLICIT_HEADERS = "implicitHeaders";
     public static final String IMPLICIT_HEADERS_REGEX = "implicitHeadersRegex";
-    public static final String AUTOSET_CONSTANTS = "autosetConstants";
     public static final String JAVAX_PACKAGE = "javaxPackage";
     public static final String USE_JAKARTA_EE = "useJakartaEe";
     public static final String CONTAINER_DEFAULT_TO_NULL = "containerDefaultToNull";
@@ -136,7 +135,6 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
     protected AnnotationLibrary annotationLibrary;
     protected boolean implicitHeaders = false;
     protected String implicitHeadersRegex = null;
-    protected boolean autosetConstants = false;
     protected boolean camelCaseDollarSign = false;
     protected boolean useJakartaEe = false;
     protected boolean containerDefaultToNull = false;
@@ -558,10 +556,6 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
             this.setImplicitHeadersRegex(additionalProperties.get(IMPLICIT_HEADERS_REGEX).toString());
         }
 
-        if (additionalProperties.containsKey(AUTOSET_CONSTANTS)) {
-            this.setAutosetConstants(Boolean.parseBoolean(additionalProperties.get(AUTOSET_CONSTANTS).toString()));
-        }
-
         if (additionalProperties.containsKey(CAMEL_CASE_DOLLAR_SIGN)) {
             this.setCamelCaseDollarSign(Boolean.parseBoolean(additionalProperties.get(CAMEL_CASE_DOLLAR_SIGN).toString()));
         }
@@ -2052,10 +2046,6 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
         this.implicitHeadersRegex = implicitHeadersRegex;
     }
 
-    public void setAutosetConstants(boolean autosetConstants) {
-        this.autosetConstants = autosetConstants;
-    }
-
     public void setCamelCaseDollarSign(boolean camelCaseDollarSign) {
         this.camelCaseDollarSign = camelCaseDollarSign;
     }
@@ -2294,45 +2284,6 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
         operation.hasParams = !operation.allParams.isEmpty();
     }
     
-    /**
-     * This method removes all constant Query, Header and Cookie Params from allParams and sets them as constantParams in the CodegenOperation.
-     * The definition of constant is single valued required enum params.
-     * The constantParams in the the generated code should be hardcoded to the constantValue if autosetConstants feature is enabled.
-     *
-     * @param operation - operation to be processed
-     */
-    protected void handleConstantParams(CodegenOperation operation) {
-        if (!autosetConstants || operation.allParams.isEmpty()) {            
-            return;
-        }
-        final ArrayList<CodegenParameter> copy = new ArrayList<>(operation.allParams);
-        // Remove all params from Params, Non constant params will be added back later.
-        operation.allParams.clear();
-
-        // Finds all constant params, removes them from allParams and adds them to constant params.
-        // Also, adds back non constant params to allParams.
-        for (CodegenParameter p : copy) {
-            if (p.isEnum && p.required && p._enum != null && p._enum.size() == 1) {
-                // Add to constantParams for use in the code generation templates. 
-                operation.constantParams.add(p);
-                if(p.isQueryParam) {
-                    operation.queryParams.removeIf(param -> param.baseName.equals(p.baseName));
-                }
-                if(p.isHeaderParam) {
-                    operation.headerParams.removeIf(param -> param.baseName.equals(p.baseName));
-                }
-                if(p.isCookieParam) {
-                    operation.cookieParams.removeIf(param -> param.baseName.equals(p.baseName));
-                }
-                LOGGER.info("Update operation [{}]. Remove parameter [{}] because it can only have a fixed value of [{}]", operation.operationId, p.baseName, p._enum.get(0));
-            } else {
-                // Add back to allParams as the param is not a constant.
-                operation.allParams.add(p);
-            }
-        }
-        operation.hasParams = !operation.allParams.isEmpty();
-    }
-
     private boolean shouldBeImplicitHeader(CodegenParameter parameter) {
         return StringUtils.isNotBlank(implicitHeadersRegex) && parameter.baseName.matches(implicitHeadersRegex);
     }

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractPythonCodegen.java

@@ -1281,6 +1281,9 @@ public abstract class AbstractPythonCodegen extends DefaultCodegen implements Co
                 }
                 operation.vendorExtensions.put("x-py-example-import", imports);
             }
+            
+            // Remove constant params from allParams list and add to constantParams
+            handleConstantParams(operation);
         }
 
         List<Map<String, String>> newImports = new ArrayList<>();

modules/openapi-generator/src/main/resources/python/api.mustache

@@ -227,6 +227,13 @@ class {{classname}}:
             {{/isArray}}
 
 {{/queryParams}}
+        {{#constantParams}}
+        {{#isQueryParam}}
+        # Set client side default value of Query Param "{{baseName}}".
+        _query_params['{{baseName}}'] = {{#_enum}}'{{{.}}}'{{/_enum}}
+
+        {{/isQueryParam}}
+        {{/constantParams}}
         # process the header parameters
         _header_params = dict(_params.get('_headers', {}))
 {{#headerParams}}
@@ -237,6 +244,13 @@ class {{classname}}:
             {{/isArray}}
 
 {{/headerParams}}
+        {{#constantParams}}
+        {{#isHeaderParam}}
+        # Set client side default value of Header Param "{{baseName}}".
+        _header_params['{{baseName}}'] = {{#_enum}}'{{{.}}}'{{/_enum}}
+
+        {{/isHeaderParam}}
+        {{/constantParams}}
         # process the form parameters
         _form_params: List[Tuple[str, str]] = []
         _files: Dict[str, str] = {}

modules/openapi-generator/src/test/java/org/openapitools/codegen/java/JavaClientCodegenTest.java

@@ -2673,6 +2673,7 @@ public class JavaClientCodegenTest {
         );
     }
 
+    @Test
     public void testHandleConstantParams() throws IOException {
         File output = Files.createTempDirectory("test").toFile().getCanonicalFile();
         output.deleteOnExit();
@@ -2682,7 +2683,7 @@ public class JavaClientCodegenTest {
         clientOptInput.openAPI(openAPI);
         JavaClientCodegen javaClientCodegen = new JavaClientCodegen();
         javaClientCodegen.setOutputDir(output.getAbsolutePath());
-        javaClientCodegen.additionalProperties().put(JavaClientCodegen.AUTOSET_CONSTANTS, "true");
+        javaClientCodegen.additionalProperties().put(CodegenConstants.AUTOSET_CONSTANTS, "true");
         javaClientCodegen.setAutosetConstants(true);
         clientOptInput.config(javaClientCodegen);
         defaultGenerator.opts(clientOptInput);

modules/openapi-generator/src/test/java/org/openapitools/codegen/python/PythonClientCodegenTest.java

@@ -17,6 +17,7 @@
 
 package org.openapitools.codegen.python;
 
+import static org.junit.Assert.assertNotNull;
 import com.google.common.collect.Sets;
 import io.swagger.parser.OpenAPIParser;
 import io.swagger.v3.oas.models.OpenAPI;
@@ -30,6 +31,7 @@ import org.openapitools.codegen.languages.features.CXFServerFeatures;
 import static org.openapitools.codegen.TestUtils.assertFileContains;
 import static org.openapitools.codegen.TestUtils.assertFileExists;
 import org.openapitools.codegen.TestUtils;
+import org.openapitools.codegen.java.assertions.JavaFileAssert;
 import org.testng.Assert;
 import org.testng.annotations.Test;
 import java.io.File;
@@ -40,6 +42,9 @@ import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
 
 public class PythonClientCodegenTest {
 
@@ -501,4 +506,28 @@ public class PythonClientCodegenTest {
         CodegenProperty property = vars.get(0);
         Assert.assertEquals(property.name, "dollar_value");
     }
+
+    @Test
+    public void testHandleConstantParams() throws IOException {
+        File output = Files.createTempDirectory("test").toFile().getCanonicalFile();
+        output.deleteOnExit();
+        final OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/3_0/java/autoset_constant.yaml");
+        final DefaultGenerator defaultGenerator = new DefaultGenerator();
+        final ClientOptInput clientOptInput = new ClientOptInput();
+        clientOptInput.openAPI(openAPI);
+        PythonClientCodegen pythonClientCodegen = new PythonClientCodegen();
+        pythonClientCodegen.setOutputDir(output.getAbsolutePath());
+        pythonClientCodegen.additionalProperties().put(CodegenConstants.AUTOSET_CONSTANTS, "true");
+        pythonClientCodegen.setAutosetConstants(true);
+        clientOptInput.config(pythonClientCodegen);
+        defaultGenerator.opts(clientOptInput);
+
+        Map<String, File> files = defaultGenerator.generate().stream()
+                .collect(Collectors.toMap(File::getPath, Function.identity()));
+
+        File apiFile = files
+                .get(Paths.get(output.getAbsolutePath(), "openapi_client", "api", "hello_example_api.py").toString());
+        assertNotNull(apiFile);
+        assertFileContains(apiFile.toPath(), "_header_params['X-CUSTOM_CONSTANT_HEADER'] = 'CONSTANT_VALUE'");
+    }
 }