From 6cdc1b5b8b7907b1e599c28fda126834e49dde47 Mon Sep 17 00:00:00 2001
From: Jan Marten <kontakt@janmarten.dev>
Date: Thu, 2 Apr 2026 16:30:11 +0200
Subject: [PATCH 1/2] fix(typescript-angular): handle Set in query parameter
 serialization (#23434)

---
 .../api.base.service.mustache                 | 11 +++---
 .../test/resources/3_0/query-param-form.yaml  | 22 ++++++++++++
 .../query-param-form/api.base.service.ts      | 11 +++---
 .../query-param-form/api/default.service.ts   | 36 ++++++++++++++-----
 .../app/src/api.query_param_form.spec.ts      | 25 +++++++++++++
 5 files changed, 87 insertions(+), 18 deletions(-)

diff --git a/modules/openapi-generator/src/main/resources/typescript-angular/api.base.service.mustache b/modules/openapi-generator/src/main/resources/typescript-angular/api.base.service.mustache
index 0b5e7c8bcf2f..ed7a92be8bd2 100644
--- a/modules/openapi-generator/src/main/resources/typescript-angular/api.base.service.mustache
+++ b/modules/openapi-generator/src/main/resources/typescript-angular/api.base.service.mustache
@@ -54,15 +54,16 @@ export class BaseService {
                 return httpParams.append(key, value.toString());
             } else if (value instanceof Date) {
                 return httpParams.append(key, value.toISOString());
-            } else if (Array.isArray(value)) {
-                // Otherwise, if it's an array, add each element.
+            } else if (Array.isArray(value) || value instanceof Set) {
+                // Otherwise, if it's an array or set, add each element.
+                const array = Array.isArray(value) ? value : Array.from(value);
                 if (paramStyle === QueryParamStyle.Form) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ','});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ','});
                 } else if (paramStyle === QueryParamStyle.SpaceDelimited) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ' '});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ' '});
                 } else {
                     // PipeDelimited
-                    return httpParams.set(key, value, {explode: explode, delimiter: '|'});
+                    return httpParams.set(key, array, {explode: explode, delimiter: '|'});
                 }
             } else {
                 // Otherwise, if it's an object, add each field.
diff --git a/modules/openapi-generator/src/test/resources/3_0/query-param-form.yaml b/modules/openapi-generator/src/test/resources/3_0/query-param-form.yaml
index 4e1f69453b12..876d3bf7d94b 100644
--- a/modules/openapi-generator/src/test/resources/3_0/query-param-form.yaml
+++ b/modules/openapi-generator/src/test/resources/3_0/query-param-form.yaml
@@ -33,6 +33,17 @@ paths:
           required: false
           schema:
             type: string
+        - in: query
+          name: tags
+          style: form
+          explode: true
+          description: Tags
+          required: false
+          schema:
+            type: array
+            items:
+              type: string
+            uniqueItems: true
       responses:
         '200':
           description: Ok
@@ -71,6 +82,17 @@ paths:
           required: false
           schema:
             type: string
+        - in: query
+          name: tags
+          style: form
+          explode: false
+          description: Tags
+          required: false
+          schema:
+            type: array
+            items:
+              type: string
+            uniqueItems: true
 
       responses:
         '200':
diff --git a/samples/client/others/typescript-angular-v20/builds/query-param-form/api.base.service.ts b/samples/client/others/typescript-angular-v20/builds/query-param-form/api.base.service.ts
index 9ff18001be21..7801405134b7 100644
--- a/samples/client/others/typescript-angular-v20/builds/query-param-form/api.base.service.ts
+++ b/samples/client/others/typescript-angular-v20/builds/query-param-form/api.base.service.ts
@@ -62,15 +62,16 @@ export class BaseService {
                 return httpParams.append(key, value.toString());
             } else if (value instanceof Date) {
                 return httpParams.append(key, value.toISOString());
-            } else if (Array.isArray(value)) {
-                // Otherwise, if it's an array, add each element.
+            } else if (Array.isArray(value) || value instanceof Set) {
+                // Otherwise, if it's an array or set, add each element.
+                const array = Array.isArray(value) ? value : Array.from(value);
                 if (paramStyle === QueryParamStyle.Form) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ','});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ','});
                 } else if (paramStyle === QueryParamStyle.SpaceDelimited) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ' '});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ' '});
                 } else {
                     // PipeDelimited
-                    return httpParams.set(key, value, {explode: explode, delimiter: '|'});
+                    return httpParams.set(key, array, {explode: explode, delimiter: '|'});
                 }
             } else {
                 // Otherwise, if it's an object, add each field.
diff --git a/samples/client/others/typescript-angular-v20/builds/query-param-form/api/default.service.ts b/samples/client/others/typescript-angular-v20/builds/query-param-form/api/default.service.ts
index 39e91beb7642..7359f92de421 100644
--- a/samples/client/others/typescript-angular-v20/builds/query-param-form/api/default.service.ts
+++ b/samples/client/others/typescript-angular-v20/builds/query-param-form/api/default.service.ts
@@ -42,14 +42,15 @@ export class DefaultService extends BaseService {
      * @param ids Ids
      * @param filter Filter
      * @param country Filter
+     * @param tags Tags
      * @param observe set whether or not to return the data Observable as the body, response or events. defaults to returning the body.
      * @param reportProgress flag to report request and response progress.
      * @param options additional options
      */
-    public searchExplode(ids?: Array<number>, filter?: Filter, country?: string, observe?: 'body', reportProgress?: boolean, options?: {httpHeaderAccept?: 'application/json', context?: HttpContext, transferCache?: boolean}): Observable<Response>;
-    public searchExplode(ids?: Array<number>, filter?: Filter, country?: string, observe?: 'response', reportProgress?: boolean, options?: {httpHeaderAccept?: 'application/json', context?: HttpContext, transferCache?: boolean}): Observable<HttpResponse<Response>>;
-    public searchExplode(ids?: Array<number>, filter?: Filter, country?: string, observe?: 'events', reportProgress?: boolean, options?: {httpHeaderAccept?: 'application/json', context?: HttpContext, transferCache?: boolean}): Observable<HttpEvent<Response>>;
-    public searchExplode(ids?: Array<number>, filter?: Filter, country?: string, observe: any = 'body', reportProgress: boolean = false, options?: {httpHeaderAccept?: 'application/json', context?: HttpContext, transferCache?: boolean}): Observable<any> {
+    public searchExplode(ids?: Array<number>, filter?: Filter, country?: string, tags?: Set<string>, observe?: 'body', reportProgress?: boolean, options?: {httpHeaderAccept?: 'application/json', context?: HttpContext, transferCache?: boolean}): Observable<Response>;
+    public searchExplode(ids?: Array<number>, filter?: Filter, country?: string, tags?: Set<string>, observe?: 'response', reportProgress?: boolean, options?: {httpHeaderAccept?: 'application/json', context?: HttpContext, transferCache?: boolean}): Observable<HttpResponse<Response>>;
+    public searchExplode(ids?: Array<number>, filter?: Filter, country?: string, tags?: Set<string>, observe?: 'events', reportProgress?: boolean, options?: {httpHeaderAccept?: 'application/json', context?: HttpContext, transferCache?: boolean}): Observable<HttpEvent<Response>>;
+    public searchExplode(ids?: Array<number>, filter?: Filter, country?: string, tags?: Set<string>, observe: any = 'body', reportProgress: boolean = false, options?: {httpHeaderAccept?: 'application/json', context?: HttpContext, transferCache?: boolean}): Observable<any> {
 
         let localVarQueryParameters = new OpenApiHttpParams(this.encoder);
 
@@ -80,6 +81,15 @@ export class DefaultService extends BaseService {
         );
 
 
+        localVarQueryParameters = this.addToHttpParams(
+            localVarQueryParameters,
+            'tags',
+            <any>tags,
+            QueryParamStyle.Form,
+            true,
+        );
+
+
         let localVarHeaders = this.defaultHeaders;
 
         const localVarHttpHeaderAcceptSelected: string | undefined = options?.httpHeaderAccept ?? this.configuration.selectHeaderAccept([
@@ -126,14 +136,15 @@ export class DefaultService extends BaseService {
      * @param ids Ids
      * @param filter Filter
      * @param country Filter
+     * @param tags Tags
      * @param observe set whether or not to return the data Observable as the body, response or events. defaults to returning the body.
      * @param reportProgress flag to report request and response progress.
      * @param options additional options
      */
-    public searchNotExplode(ids?: Array<number>, filter?: Filter, country?: string, observe?: 'body', reportProgress?: boolean, options?: {httpHeaderAccept?: 'application/json', context?: HttpContext, transferCache?: boolean}): Observable<Response>;
-    public searchNotExplode(ids?: Array<number>, filter?: Filter, country?: string, observe?: 'response', reportProgress?: boolean, options?: {httpHeaderAccept?: 'application/json', context?: HttpContext, transferCache?: boolean}): Observable<HttpResponse<Response>>;
-    public searchNotExplode(ids?: Array<number>, filter?: Filter, country?: string, observe?: 'events', reportProgress?: boolean, options?: {httpHeaderAccept?: 'application/json', context?: HttpContext, transferCache?: boolean}): Observable<HttpEvent<Response>>;
-    public searchNotExplode(ids?: Array<number>, filter?: Filter, country?: string, observe: any = 'body', reportProgress: boolean = false, options?: {httpHeaderAccept?: 'application/json', context?: HttpContext, transferCache?: boolean}): Observable<any> {
+    public searchNotExplode(ids?: Array<number>, filter?: Filter, country?: string, tags?: Set<string>, observe?: 'body', reportProgress?: boolean, options?: {httpHeaderAccept?: 'application/json', context?: HttpContext, transferCache?: boolean}): Observable<Response>;
+    public searchNotExplode(ids?: Array<number>, filter?: Filter, country?: string, tags?: Set<string>, observe?: 'response', reportProgress?: boolean, options?: {httpHeaderAccept?: 'application/json', context?: HttpContext, transferCache?: boolean}): Observable<HttpResponse<Response>>;
+    public searchNotExplode(ids?: Array<number>, filter?: Filter, country?: string, tags?: Set<string>, observe?: 'events', reportProgress?: boolean, options?: {httpHeaderAccept?: 'application/json', context?: HttpContext, transferCache?: boolean}): Observable<HttpEvent<Response>>;
+    public searchNotExplode(ids?: Array<number>, filter?: Filter, country?: string, tags?: Set<string>, observe: any = 'body', reportProgress: boolean = false, options?: {httpHeaderAccept?: 'application/json', context?: HttpContext, transferCache?: boolean}): Observable<any> {
 
         let localVarQueryParameters = new OpenApiHttpParams(this.encoder);
 
@@ -164,6 +175,15 @@ export class DefaultService extends BaseService {
         );
 
 
+        localVarQueryParameters = this.addToHttpParams(
+            localVarQueryParameters,
+            'tags',
+            <any>tags,
+            QueryParamStyle.Form,
+            false,
+        );
+
+
         let localVarHeaders = this.defaultHeaders;
 
         const localVarHttpHeaderAcceptSelected: string | undefined = options?.httpHeaderAccept ?? this.configuration.selectHeaderAccept([
diff --git a/samples/client/others/typescript-angular-v20/projects/app/src/api.query_param_form.spec.ts b/samples/client/others/typescript-angular-v20/projects/app/src/api.query_param_form.spec.ts
index 1ad044f71b55..d0994e2a8822 100644
--- a/samples/client/others/typescript-angular-v20/projects/app/src/api.query_param_form.spec.ts
+++ b/samples/client/others/typescript-angular-v20/projects/app/src/api.query_param_form.spec.ts
@@ -8,6 +8,7 @@ const ids: number[] = [4, 5];
 const filter: Filter = {name: 'John', age: 37, nicknames: ['Joe', 'Joey']};
 const filterWithSpecialCharacters: Filter = {name: 'Éléonore &,|+', age: 42, nicknames: ['Elé', 'Ellie']};
 const country: string = "Belgium";
+const tags: Set<string> = new Set(['a', 'b']);
 
 describe('Form Query Param testing', () => {
   let httpTesting: HttpTestingController;
@@ -80,6 +81,18 @@ describe('Form Query Param testing', () => {
     expect(req.request.method).toEqual('GET');
   });
 
+  it('should separate the query parameter with ampersands (set only)', async () => {
+    service.searchExplode(undefined, undefined, undefined, tags).subscribe();
+    const req = httpTesting.expectOne('http://localhost/search_explode?tags=a&tags=b');
+    expect(req.request.method).toEqual('GET');
+  });
+
+  it('should separate the query parameter with ampersands (all set including tags)', async () => {
+    service.searchExplode(ids, filter, country, tags).subscribe();
+    const req = httpTesting.expectOne('http://localhost/search_explode?ids=4&ids=5&name=John&age=37&nicknames=Joe&nicknames=Joey&country=Belgium&tags=a&tags=b');
+    expect(req.request.method).toEqual('GET');
+  });
+
   it('should separate the query parameter with comma (all set)', async () => {
     service.searchNotExplode(ids, filter, country).subscribe();
     const req = httpTesting.expectOne('http://localhost/search_not_explode?ids=4,5&filter=name,John,age,37,nicknames,Joe,Joey&country=Belgium');
@@ -126,4 +139,16 @@ describe('Form Query Param testing', () => {
     expect(req.request.method).toEqual('GET');
   });
 
+  it('should separate the query parameter with comma (set only)', async () => {
+    service.searchNotExplode(undefined, undefined, undefined, tags).subscribe();
+    const req = httpTesting.expectOne('http://localhost/search_not_explode?tags=a,b');
+    expect(req.request.method).toEqual('GET');
+  });
+
+  it('should separate the query parameter with comma (all set including tags)', async () => {
+    service.searchNotExplode(ids, filter, country, tags).subscribe();
+    const req = httpTesting.expectOne('http://localhost/search_not_explode?ids=4,5&filter=name,John,age,37,nicknames,Joe,Joey&country=Belgium&tags=a,b');
+    expect(req.request.method).toEqual('GET');
+  });
+
 });

From efab0a870c94d3e5611e2f7b2a1e5f423ca4a711 Mon Sep 17 00:00:00 2001
From: Jan Marten <kontakt@janmarten.dev>
Date: Wed, 8 Apr 2026 07:31:24 +0200
Subject: [PATCH 2/2] Update sample files

---
 .../query-param-deep-object/api.base.service.ts       | 11 ++++++-----
 .../builds/query-param-json/api.base.service.ts       | 11 ++++++-----
 .../api.base.service.ts                               | 11 ++++++-----
 .../builds/composed-schemas/api.base.service.ts       | 11 ++++++-----
 .../builds/default/api.base.service.ts                | 11 ++++++-----
 .../builds/default/api.base.service.ts                | 11 ++++++-----
 .../builds/default/api.base.service.ts                | 11 ++++++-----
 .../builds/default/api.base.service.ts                | 11 ++++++-----
 .../builds/default/api.base.service.ts                | 11 ++++++-----
 .../builds/default/api.base.service.ts                | 11 ++++++-----
 .../builds/default/api.base.service.ts                | 11 ++++++-----
 .../builds/default/api.base.service.ts                | 11 ++++++-----
 .../builds/default/api.base.service.ts                | 11 ++++++-----
 .../builds/default/api.base.service.ts                | 11 ++++++-----
 14 files changed, 84 insertions(+), 70 deletions(-)

diff --git a/samples/client/others/typescript-angular-v20/builds/query-param-deep-object/api.base.service.ts b/samples/client/others/typescript-angular-v20/builds/query-param-deep-object/api.base.service.ts
index 8158930d1326..1b63f4457d9c 100644
--- a/samples/client/others/typescript-angular-v20/builds/query-param-deep-object/api.base.service.ts
+++ b/samples/client/others/typescript-angular-v20/builds/query-param-deep-object/api.base.service.ts
@@ -62,15 +62,16 @@ export class BaseService {
                 return httpParams.append(key, value.toString());
             } else if (value instanceof Date) {
                 return httpParams.append(key, value.toISOString());
-            } else if (Array.isArray(value)) {
-                // Otherwise, if it's an array, add each element.
+            } else if (Array.isArray(value) || value instanceof Set) {
+                // Otherwise, if it's an array or set, add each element.
+                const array = Array.isArray(value) ? value : Array.from(value);
                 if (paramStyle === QueryParamStyle.Form) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ','});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ','});
                 } else if (paramStyle === QueryParamStyle.SpaceDelimited) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ' '});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ' '});
                 } else {
                     // PipeDelimited
-                    return httpParams.set(key, value, {explode: explode, delimiter: '|'});
+                    return httpParams.set(key, array, {explode: explode, delimiter: '|'});
                 }
             } else {
                 // Otherwise, if it's an object, add each field.
diff --git a/samples/client/others/typescript-angular-v20/builds/query-param-json/api.base.service.ts b/samples/client/others/typescript-angular-v20/builds/query-param-json/api.base.service.ts
index 70c3d4896bac..56df5e8f84b6 100644
--- a/samples/client/others/typescript-angular-v20/builds/query-param-json/api.base.service.ts
+++ b/samples/client/others/typescript-angular-v20/builds/query-param-json/api.base.service.ts
@@ -62,15 +62,16 @@ export class BaseService {
                 return httpParams.append(key, value.toString());
             } else if (value instanceof Date) {
                 return httpParams.append(key, value.toISOString());
-            } else if (Array.isArray(value)) {
-                // Otherwise, if it's an array, add each element.
+            } else if (Array.isArray(value) || value instanceof Set) {
+                // Otherwise, if it's an array or set, add each element.
+                const array = Array.isArray(value) ? value : Array.from(value);
                 if (paramStyle === QueryParamStyle.Form) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ','});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ','});
                 } else if (paramStyle === QueryParamStyle.SpaceDelimited) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ' '});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ' '});
                 } else {
                     // PipeDelimited
-                    return httpParams.set(key, value, {explode: explode, delimiter: '|'});
+                    return httpParams.set(key, array, {explode: explode, delimiter: '|'});
                 }
             } else {
                 // Otherwise, if it's an object, add each field.
diff --git a/samples/client/others/typescript-angular/builds/composed-schemas-tagged-unions/api.base.service.ts b/samples/client/others/typescript-angular/builds/composed-schemas-tagged-unions/api.base.service.ts
index 2cb82afac792..da9512f79726 100644
--- a/samples/client/others/typescript-angular/builds/composed-schemas-tagged-unions/api.base.service.ts
+++ b/samples/client/others/typescript-angular/builds/composed-schemas-tagged-unions/api.base.service.ts
@@ -62,15 +62,16 @@ export class BaseService {
                 return httpParams.append(key, value.toString());
             } else if (value instanceof Date) {
                 return httpParams.append(key, value.toISOString());
-            } else if (Array.isArray(value)) {
-                // Otherwise, if it's an array, add each element.
+            } else if (Array.isArray(value) || value instanceof Set) {
+                // Otherwise, if it's an array or set, add each element.
+                const array = Array.isArray(value) ? value : Array.from(value);
                 if (paramStyle === QueryParamStyle.Form) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ','});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ','});
                 } else if (paramStyle === QueryParamStyle.SpaceDelimited) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ' '});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ' '});
                 } else {
                     // PipeDelimited
-                    return httpParams.set(key, value, {explode: explode, delimiter: '|'});
+                    return httpParams.set(key, array, {explode: explode, delimiter: '|'});
                 }
             } else {
                 // Otherwise, if it's an object, add each field.
diff --git a/samples/client/others/typescript-angular/builds/composed-schemas/api.base.service.ts b/samples/client/others/typescript-angular/builds/composed-schemas/api.base.service.ts
index 2cb82afac792..da9512f79726 100644
--- a/samples/client/others/typescript-angular/builds/composed-schemas/api.base.service.ts
+++ b/samples/client/others/typescript-angular/builds/composed-schemas/api.base.service.ts
@@ -62,15 +62,16 @@ export class BaseService {
                 return httpParams.append(key, value.toString());
             } else if (value instanceof Date) {
                 return httpParams.append(key, value.toISOString());
-            } else if (Array.isArray(value)) {
-                // Otherwise, if it's an array, add each element.
+            } else if (Array.isArray(value) || value instanceof Set) {
+                // Otherwise, if it's an array or set, add each element.
+                const array = Array.isArray(value) ? value : Array.from(value);
                 if (paramStyle === QueryParamStyle.Form) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ','});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ','});
                 } else if (paramStyle === QueryParamStyle.SpaceDelimited) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ' '});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ' '});
                 } else {
                     // PipeDelimited
-                    return httpParams.set(key, value, {explode: explode, delimiter: '|'});
+                    return httpParams.set(key, array, {explode: explode, delimiter: '|'});
                 }
             } else {
                 // Otherwise, if it's an object, add each field.
diff --git a/samples/client/petstore/typescript-angular-v16-provided-in-root/builds/default/api.base.service.ts b/samples/client/petstore/typescript-angular-v16-provided-in-root/builds/default/api.base.service.ts
index 225e5863dcf2..8a8b8bc6b6f5 100644
--- a/samples/client/petstore/typescript-angular-v16-provided-in-root/builds/default/api.base.service.ts
+++ b/samples/client/petstore/typescript-angular-v16-provided-in-root/builds/default/api.base.service.ts
@@ -62,15 +62,16 @@ export class BaseService {
                 return httpParams.append(key, value.toString());
             } else if (value instanceof Date) {
                 return httpParams.append(key, value.toISOString());
-            } else if (Array.isArray(value)) {
-                // Otherwise, if it's an array, add each element.
+            } else if (Array.isArray(value) || value instanceof Set) {
+                // Otherwise, if it's an array or set, add each element.
+                const array = Array.isArray(value) ? value : Array.from(value);
                 if (paramStyle === QueryParamStyle.Form) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ','});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ','});
                 } else if (paramStyle === QueryParamStyle.SpaceDelimited) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ' '});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ' '});
                 } else {
                     // PipeDelimited
-                    return httpParams.set(key, value, {explode: explode, delimiter: '|'});
+                    return httpParams.set(key, array, {explode: explode, delimiter: '|'});
                 }
             } else {
                 // Otherwise, if it's an object, add each field.
diff --git a/samples/client/petstore/typescript-angular-v17-provided-in-root/builds/default/api.base.service.ts b/samples/client/petstore/typescript-angular-v17-provided-in-root/builds/default/api.base.service.ts
index 225e5863dcf2..8a8b8bc6b6f5 100644
--- a/samples/client/petstore/typescript-angular-v17-provided-in-root/builds/default/api.base.service.ts
+++ b/samples/client/petstore/typescript-angular-v17-provided-in-root/builds/default/api.base.service.ts
@@ -62,15 +62,16 @@ export class BaseService {
                 return httpParams.append(key, value.toString());
             } else if (value instanceof Date) {
                 return httpParams.append(key, value.toISOString());
-            } else if (Array.isArray(value)) {
-                // Otherwise, if it's an array, add each element.
+            } else if (Array.isArray(value) || value instanceof Set) {
+                // Otherwise, if it's an array or set, add each element.
+                const array = Array.isArray(value) ? value : Array.from(value);
                 if (paramStyle === QueryParamStyle.Form) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ','});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ','});
                 } else if (paramStyle === QueryParamStyle.SpaceDelimited) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ' '});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ' '});
                 } else {
                     // PipeDelimited
-                    return httpParams.set(key, value, {explode: explode, delimiter: '|'});
+                    return httpParams.set(key, array, {explode: explode, delimiter: '|'});
                 }
             } else {
                 // Otherwise, if it's an object, add each field.
diff --git a/samples/client/petstore/typescript-angular-v18-provided-in-root/builds/default/api.base.service.ts b/samples/client/petstore/typescript-angular-v18-provided-in-root/builds/default/api.base.service.ts
index 225e5863dcf2..8a8b8bc6b6f5 100644
--- a/samples/client/petstore/typescript-angular-v18-provided-in-root/builds/default/api.base.service.ts
+++ b/samples/client/petstore/typescript-angular-v18-provided-in-root/builds/default/api.base.service.ts
@@ -62,15 +62,16 @@ export class BaseService {
                 return httpParams.append(key, value.toString());
             } else if (value instanceof Date) {
                 return httpParams.append(key, value.toISOString());
-            } else if (Array.isArray(value)) {
-                // Otherwise, if it's an array, add each element.
+            } else if (Array.isArray(value) || value instanceof Set) {
+                // Otherwise, if it's an array or set, add each element.
+                const array = Array.isArray(value) ? value : Array.from(value);
                 if (paramStyle === QueryParamStyle.Form) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ','});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ','});
                 } else if (paramStyle === QueryParamStyle.SpaceDelimited) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ' '});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ' '});
                 } else {
                     // PipeDelimited
-                    return httpParams.set(key, value, {explode: explode, delimiter: '|'});
+                    return httpParams.set(key, array, {explode: explode, delimiter: '|'});
                 }
             } else {
                 // Otherwise, if it's an object, add each field.
diff --git a/samples/client/petstore/typescript-angular-v19-provided-in-root/builds/default/api.base.service.ts b/samples/client/petstore/typescript-angular-v19-provided-in-root/builds/default/api.base.service.ts
index 225e5863dcf2..8a8b8bc6b6f5 100644
--- a/samples/client/petstore/typescript-angular-v19-provided-in-root/builds/default/api.base.service.ts
+++ b/samples/client/petstore/typescript-angular-v19-provided-in-root/builds/default/api.base.service.ts
@@ -62,15 +62,16 @@ export class BaseService {
                 return httpParams.append(key, value.toString());
             } else if (value instanceof Date) {
                 return httpParams.append(key, value.toISOString());
-            } else if (Array.isArray(value)) {
-                // Otherwise, if it's an array, add each element.
+            } else if (Array.isArray(value) || value instanceof Set) {
+                // Otherwise, if it's an array or set, add each element.
+                const array = Array.isArray(value) ? value : Array.from(value);
                 if (paramStyle === QueryParamStyle.Form) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ','});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ','});
                 } else if (paramStyle === QueryParamStyle.SpaceDelimited) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ' '});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ' '});
                 } else {
                     // PipeDelimited
-                    return httpParams.set(key, value, {explode: explode, delimiter: '|'});
+                    return httpParams.set(key, array, {explode: explode, delimiter: '|'});
                 }
             } else {
                 // Otherwise, if it's an object, add each field.
diff --git a/samples/client/petstore/typescript-angular-v19-with-angular-dependency-params/builds/default/api.base.service.ts b/samples/client/petstore/typescript-angular-v19-with-angular-dependency-params/builds/default/api.base.service.ts
index 225e5863dcf2..8a8b8bc6b6f5 100644
--- a/samples/client/petstore/typescript-angular-v19-with-angular-dependency-params/builds/default/api.base.service.ts
+++ b/samples/client/petstore/typescript-angular-v19-with-angular-dependency-params/builds/default/api.base.service.ts
@@ -62,15 +62,16 @@ export class BaseService {
                 return httpParams.append(key, value.toString());
             } else if (value instanceof Date) {
                 return httpParams.append(key, value.toISOString());
-            } else if (Array.isArray(value)) {
-                // Otherwise, if it's an array, add each element.
+            } else if (Array.isArray(value) || value instanceof Set) {
+                // Otherwise, if it's an array or set, add each element.
+                const array = Array.isArray(value) ? value : Array.from(value);
                 if (paramStyle === QueryParamStyle.Form) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ','});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ','});
                 } else if (paramStyle === QueryParamStyle.SpaceDelimited) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ' '});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ' '});
                 } else {
                     // PipeDelimited
-                    return httpParams.set(key, value, {explode: explode, delimiter: '|'});
+                    return httpParams.set(key, array, {explode: explode, delimiter: '|'});
                 }
             } else {
                 // Otherwise, if it's an object, add each field.
diff --git a/samples/client/petstore/typescript-angular-v19/builds/default/api.base.service.ts b/samples/client/petstore/typescript-angular-v19/builds/default/api.base.service.ts
index 225e5863dcf2..8a8b8bc6b6f5 100644
--- a/samples/client/petstore/typescript-angular-v19/builds/default/api.base.service.ts
+++ b/samples/client/petstore/typescript-angular-v19/builds/default/api.base.service.ts
@@ -62,15 +62,16 @@ export class BaseService {
                 return httpParams.append(key, value.toString());
             } else if (value instanceof Date) {
                 return httpParams.append(key, value.toISOString());
-            } else if (Array.isArray(value)) {
-                // Otherwise, if it's an array, add each element.
+            } else if (Array.isArray(value) || value instanceof Set) {
+                // Otherwise, if it's an array or set, add each element.
+                const array = Array.isArray(value) ? value : Array.from(value);
                 if (paramStyle === QueryParamStyle.Form) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ','});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ','});
                 } else if (paramStyle === QueryParamStyle.SpaceDelimited) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ' '});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ' '});
                 } else {
                     // PipeDelimited
-                    return httpParams.set(key, value, {explode: explode, delimiter: '|'});
+                    return httpParams.set(key, array, {explode: explode, delimiter: '|'});
                 }
             } else {
                 // Otherwise, if it's an object, add each field.
diff --git a/samples/client/petstore/typescript-angular-v20-provided-in-root/builds/default/api.base.service.ts b/samples/client/petstore/typescript-angular-v20-provided-in-root/builds/default/api.base.service.ts
index 225e5863dcf2..8a8b8bc6b6f5 100644
--- a/samples/client/petstore/typescript-angular-v20-provided-in-root/builds/default/api.base.service.ts
+++ b/samples/client/petstore/typescript-angular-v20-provided-in-root/builds/default/api.base.service.ts
@@ -62,15 +62,16 @@ export class BaseService {
                 return httpParams.append(key, value.toString());
             } else if (value instanceof Date) {
                 return httpParams.append(key, value.toISOString());
-            } else if (Array.isArray(value)) {
-                // Otherwise, if it's an array, add each element.
+            } else if (Array.isArray(value) || value instanceof Set) {
+                // Otherwise, if it's an array or set, add each element.
+                const array = Array.isArray(value) ? value : Array.from(value);
                 if (paramStyle === QueryParamStyle.Form) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ','});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ','});
                 } else if (paramStyle === QueryParamStyle.SpaceDelimited) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ' '});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ' '});
                 } else {
                     // PipeDelimited
-                    return httpParams.set(key, value, {explode: explode, delimiter: '|'});
+                    return httpParams.set(key, array, {explode: explode, delimiter: '|'});
                 }
             } else {
                 // Otherwise, if it's an object, add each field.
diff --git a/samples/client/petstore/typescript-angular-v20/builds/default/api.base.service.ts b/samples/client/petstore/typescript-angular-v20/builds/default/api.base.service.ts
index 225e5863dcf2..8a8b8bc6b6f5 100644
--- a/samples/client/petstore/typescript-angular-v20/builds/default/api.base.service.ts
+++ b/samples/client/petstore/typescript-angular-v20/builds/default/api.base.service.ts
@@ -62,15 +62,16 @@ export class BaseService {
                 return httpParams.append(key, value.toString());
             } else if (value instanceof Date) {
                 return httpParams.append(key, value.toISOString());
-            } else if (Array.isArray(value)) {
-                // Otherwise, if it's an array, add each element.
+            } else if (Array.isArray(value) || value instanceof Set) {
+                // Otherwise, if it's an array or set, add each element.
+                const array = Array.isArray(value) ? value : Array.from(value);
                 if (paramStyle === QueryParamStyle.Form) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ','});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ','});
                 } else if (paramStyle === QueryParamStyle.SpaceDelimited) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ' '});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ' '});
                 } else {
                     // PipeDelimited
-                    return httpParams.set(key, value, {explode: explode, delimiter: '|'});
+                    return httpParams.set(key, array, {explode: explode, delimiter: '|'});
                 }
             } else {
                 // Otherwise, if it's an object, add each field.
diff --git a/samples/client/petstore/typescript-angular-v21-provided-in-root/builds/default/api.base.service.ts b/samples/client/petstore/typescript-angular-v21-provided-in-root/builds/default/api.base.service.ts
index 225e5863dcf2..8a8b8bc6b6f5 100644
--- a/samples/client/petstore/typescript-angular-v21-provided-in-root/builds/default/api.base.service.ts
+++ b/samples/client/petstore/typescript-angular-v21-provided-in-root/builds/default/api.base.service.ts
@@ -62,15 +62,16 @@ export class BaseService {
                 return httpParams.append(key, value.toString());
             } else if (value instanceof Date) {
                 return httpParams.append(key, value.toISOString());
-            } else if (Array.isArray(value)) {
-                // Otherwise, if it's an array, add each element.
+            } else if (Array.isArray(value) || value instanceof Set) {
+                // Otherwise, if it's an array or set, add each element.
+                const array = Array.isArray(value) ? value : Array.from(value);
                 if (paramStyle === QueryParamStyle.Form) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ','});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ','});
                 } else if (paramStyle === QueryParamStyle.SpaceDelimited) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ' '});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ' '});
                 } else {
                     // PipeDelimited
-                    return httpParams.set(key, value, {explode: explode, delimiter: '|'});
+                    return httpParams.set(key, array, {explode: explode, delimiter: '|'});
                 }
             } else {
                 // Otherwise, if it's an object, add each field.
diff --git a/samples/client/petstore/typescript-angular-v21/builds/default/api.base.service.ts b/samples/client/petstore/typescript-angular-v21/builds/default/api.base.service.ts
index 225e5863dcf2..8a8b8bc6b6f5 100644
--- a/samples/client/petstore/typescript-angular-v21/builds/default/api.base.service.ts
+++ b/samples/client/petstore/typescript-angular-v21/builds/default/api.base.service.ts
@@ -62,15 +62,16 @@ export class BaseService {
                 return httpParams.append(key, value.toString());
             } else if (value instanceof Date) {
                 return httpParams.append(key, value.toISOString());
-            } else if (Array.isArray(value)) {
-                // Otherwise, if it's an array, add each element.
+            } else if (Array.isArray(value) || value instanceof Set) {
+                // Otherwise, if it's an array or set, add each element.
+                const array = Array.isArray(value) ? value : Array.from(value);
                 if (paramStyle === QueryParamStyle.Form) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ','});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ','});
                 } else if (paramStyle === QueryParamStyle.SpaceDelimited) {
-                    return httpParams.set(key, value, {explode: explode, delimiter: ' '});
+                    return httpParams.set(key, array, {explode: explode, delimiter: ' '});
                 } else {
                     // PipeDelimited
-                    return httpParams.set(key, value, {explode: explode, delimiter: '|'});
+                    return httpParams.set(key, array, {explode: explode, delimiter: '|'});
                 }
             } else {
                 // Otherwise, if it's an object, add each field.