[Go] skip validator import if oneOf discriminator lookup is enabled (#20497)

* move validator import into GoClientCodegen

* add new example for oneof discriminator lookup

* regenerate samples

* add validator.v2 to go.mod if it is imported

* regenerate samples

Author: ctreatma

bin/configs/go-oneof-discriminator-lookup.yaml

@@ -0,0 +1,6 @@
+generatorName: go
+outputDir: samples/client/others/go/oneof-discriminator-lookup
+inputSpec: modules/openapi-generator/src/test/resources/3_0/go/spec-with-oneof-discriminator.yaml
+additionalProperties:
+  useOneOfDiscriminatorLookup: "true"
+  hideGenerationTimestamp: "true"

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

@@ -748,7 +748,6 @@ public ModelsMap postProcessModels(ModelsMap objs) {
         for (ModelMap m : objs.getModels()) {
             boolean addedTimeImport = false;
             boolean addedOSImport = false;
-            boolean addedValidator = false;
             CodegenModel model = m.getModel();
 
             List<CodegenProperty> inheritedProperties = new ArrayList<>();
@@ -830,11 +829,6 @@ public ModelsMap postProcessModels(ModelsMap objs) {
                 imports.add(createMapping("import", "fmt"));
             }
 
-            if (model.oneOf != null && !model.oneOf.isEmpty() && !addedValidator && generateUnmarshalJSON) {
-                imports.add(createMapping("import", "gopkg.in/validator.v2"));
-                addedValidator = true;
-            }
-
             // if oneOf contains "null" type
             if (model.oneOf != null && !model.oneOf.isEmpty() && model.oneOf.contains("nil")) {
                 model.isNullable = true;

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

@@ -56,6 +56,7 @@ public class GoClientCodegen extends AbstractGoCodegen {
     public static final String MODEL_FILE_FOLDER = "modelFileFolder";
     public static final String WITH_GO_MOD = "withGoMod";
     public static final String USE_DEFAULT_VALUES_FOR_REQUIRED_VARS = "useDefaultValuesForRequiredVars";
+    public static final String IMPORT_VALIDATOR = "importValidator";
     @Setter protected String goImportAlias = "openapiclient";
     protected boolean isGoSubmodule = false;
     @Setter protected boolean useOneOfDiscriminatorLookup = false; // use oneOf discriminator's mapping for model lookup
@@ -494,6 +495,11 @@ public ModelsMap postProcessModels(ModelsMap objs) {
             if (model.oneOf != null && !model.oneOf.isEmpty()) {
                 imports.add(createMapping("import", "fmt"));
                 addedFmtImport = true;
+
+                if (generateUnmarshalJSON && !useOneOfDiscriminatorLookup) {
+                    imports.add(createMapping("import", "gopkg.in/validator.v2"));
+                    additionalProperties.put(IMPORT_VALIDATOR, true);
+                }
             }
 
             // anyOf

modules/openapi-generator/src/main/resources/go/go.mod.mustache

@@ -9,4 +9,7 @@ require (
 	{{#withAWSV4Signature}}
 	github.com/aws/aws-sdk-go v1.34.14
 	{{/withAWSV4Signature}}
+	{{#importValidator}}
+	gopkg.in/validator.v2 v2.0.1
+	{{/importValidator}}
 )

modules/openapi-generator/src/main/resources/go/go.sum.mustache

@@ -13,3 +13,7 @@ golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 google.golang.org/appengine v1.4.0 h1:/wp5JvzpHIxhs/dumFmF7BXTf3Z+dd4uXta4kVyO508=
 google.golang.org/appengine v1.4.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=
+{{#importValidator}}
+gopkg.in/validator.v2 v2.0.1 h1:xF0KWyGWXm/LM2G1TrEjqOu4pa6coO9AlWSf3msVfDY=
+gopkg.in/validator.v2 v2.0.1/go.mod h1:lIUZBlB3Im4s/eYp39Ry/wkR02yOPhZ9IwIRBjuPuG8=
+{{/importValidator}}

modules/openapi-generator/src/test/resources/3_0/go/spec-with-oneof-discriminator.yaml

@@ -0,0 +1,34 @@
+openapi: 3.0.0
+info:
+  title: Test
+  version: 1.0.0
+paths: {}
+components:
+  schemas:
+    NestedObject1:
+      required:
+        - field1
+      properties:
+        field1:
+          description: Specifies an action name to be used with the Android Intent class.
+          type: string
+        type:
+          type: string
+    NestedObject2:
+      required:
+        - field2
+      properties:
+        field1:
+          description: Specifies an action name to be used with the Android Intent class.
+          type: string
+        type:
+          type: string
+    Object:
+      oneOf:
+        - $ref: '#/components/schemas/NestedObject1'
+        - $ref: '#/components/schemas/NestedObject2'
+      discriminator:
+        propertyName: type
+        mapping:
+          ONE: '#/components/schemas/NestedObject1'
+          TWO: '#/components/schemas/NestedObject2'

samples/client/others/go/oneof-anyof-required/go.mod

@@ -3,4 +3,5 @@ module github.com/GIT_USER_ID/GIT_REPO_ID
 go 1.18
 
 require (
+	gopkg.in/validator.v2 v2.0.1
 )

samples/client/others/go/oneof-anyof-required/go.sum

@@ -9,3 +9,5 @@ golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 google.golang.org/appengine v1.4.0 h1:/wp5JvzpHIxhs/dumFmF7BXTf3Z+dd4uXta4kVyO508=
 google.golang.org/appengine v1.4.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=
+gopkg.in/validator.v2 v2.0.1 h1:xF0KWyGWXm/LM2G1TrEjqOu4pa6coO9AlWSf3msVfDY=
+gopkg.in/validator.v2 v2.0.1/go.mod h1:lIUZBlB3Im4s/eYp39Ry/wkR02yOPhZ9IwIRBjuPuG8=

samples/client/others/go/oneof-anyof-required/model_object.go

@@ -0,0 +1,24 @@
+# Compiled Object files, Static and Dynamic libs (Shared Objects)
+*.o
+*.a
+*.so
+
+# Folders
+_obj
+_test
+
+# Architecture specific extensions/prefixes
+*.[568vq]
+[568vq].out
+
+*.cgo1.go
+*.cgo2.c
+_cgo_defun.c
+_cgo_gotypes.go
+_cgo_export.*
+
+_testmain.go
+
+*.exe
+*.test
+*.prof