fix(core): Resolve Custom API Call support through inherited credential types (#35820)

packages/cli/src/__tests__/load-nodes-and-credentials.test.ts

@@ -6,10 +6,12 @@ import { Service } from '@n8n/di';
 import watcher from '@parcel/watcher';
 import fs from 'fs/promises';
 import { CUSTOM_NODES_PACKAGE_NAME, DirectoryLoader } from 'n8n-core';
-import type { INodeProperties, INodeTypeDescription } from 'n8n-workflow';
+import type { ICredentialType, INodeProperties, INodeTypeDescription } from 'n8n-workflow';
 import type { Mock } from 'vitest';
 import { mock } from 'vitest-mock-extended';
 
+import { CUSTOM_API_CALL_KEY, CUSTOM_API_CALL_NAME } from '@/constants';
+
 import { LoadNodesAndCredentials } from '../load-nodes-and-credentials';
 
 vi.mock('lodash/debounce', () => ({ default: (fn: () => void) => fn }));
@@ -515,6 +517,97 @@ describe('LoadNodesAndCredentials', () => {
 		});
 	});
 
+	describe('injectCustomApiCallOptions', () => {
+		let instance: LoadNodesAndCredentials;
+
+		const makeNode = (credentialName: string): INodeTypeDescription => ({
+			name: 'n8n-nodes-base.test',
+			displayName: 'Test',
+			group: ['transform'],
+			description: 'Test node',
+			version: 1,
+			defaults: {},
+			inputs: [],
+			outputs: ['main'],
+			properties: [
+				{
+					displayName: 'Resource',
+					name: 'resource',
+					type: 'options',
+					options: [{ name: 'Page', value: 'page' }],
+					default: 'page',
+				},
+			],
+			credentials: [{ name: credentialName }],
+		});
+
+		const makeCredential = (name: string, extendsTypes?: string[]): ICredentialType => ({
+			name,
+			displayName: name,
+			properties: [],
+			...(extendsTypes ? { extends: extendsTypes } : {}),
+		});
+
+		const injectedOption = { name: CUSTOM_API_CALL_NAME, value: CUSTOM_API_CALL_KEY };
+
+		beforeEach(() => {
+			instance = new LoadNodesAndCredentials(mock(), mock(), mock(), mock(), mock(), mock());
+		});
+
+		it('should inject the option when a credential extends a base OAuth type directly', () => {
+			const node = makeNode('slackOAuth2Api');
+			instance.types.nodes = [node];
+			instance.types.credentials = [makeCredential('slackOAuth2Api', ['oAuth2Api'])];
+
+			// eslint-disable-next-line @typescript-eslint/no-explicit-any
+			(instance as any).injectCustomApiCallOptions();
+
+			expect(node.properties[0].options).toEqual([{ name: 'Page', value: 'page' }, injectedOption]);
+		});
+
+		it('should inject the option when a credential reaches a base OAuth type through an intermediate', () => {
+			const node = makeNode('confluenceCloudOAuth2Api');
+			instance.types.nodes = [node];
+			instance.types.credentials = [
+				makeCredential('confluenceCloudOAuth2Api', ['atlassianOAuth2Api']),
+				makeCredential('atlassianOAuth2Api', ['oAuth2Api']),
+			];
+
+			// eslint-disable-next-line @typescript-eslint/no-explicit-any
+			(instance as any).injectCustomApiCallOptions();
+
+			expect(node.properties[0].options).toEqual([{ name: 'Page', value: 'page' }, injectedOption]);
+		});
+
+		it('should not inject the option when the extends chain never reaches a base OAuth type', () => {
+			const node = makeNode('someApi');
+			instance.types.nodes = [node];
+			instance.types.credentials = [
+				makeCredential('someApi', ['intermediateApi']),
+				makeCredential('intermediateApi'),
+			];
+
+			// eslint-disable-next-line @typescript-eslint/no-explicit-any
+			(instance as any).injectCustomApiCallOptions();
+
+			expect(node.properties[0].options).toEqual([{ name: 'Page', value: 'page' }]);
+		});
+
+		it('should not loop on a cyclic extends chain', () => {
+			const node = makeNode('cyclicApi');
+			instance.types.nodes = [node];
+			instance.types.credentials = [
+				makeCredential('cyclicApi', ['otherCyclicApi']),
+				makeCredential('otherCyclicApi', ['cyclicApi']),
+			];
+
+			// eslint-disable-next-line @typescript-eslint/no-explicit-any
+			(instance as any).injectCustomApiCallOptions();
+
+			expect(node.properties[0].options).toEqual([{ name: 'Page', value: 'page' }]);
+		});
+	});
+
 	describe('setupHotReload', () => {
 		let instance: LoadNodesAndCredentials;
 

packages/cli/src/load-nodes-and-credentials.ts

@@ -351,12 +351,26 @@ export class LoadNodesAndCredentials {
 			}
 			if (credType.authenticate !== undefined) return true;
 
-			return (
-				Array.isArray(credType.extends) &&
-				credType.extends.some((parentType) =>
-					['oAuth2Api', 'googleOAuth2Api', 'oAuth1Api'].includes(parentType),
-				)
-			);
+			return this.extendsProxyAuthBaseType(credType);
+		});
+	}
+
+	/**
+	 * Whether a credential type reaches one of the OAuth base types through its
+	 * `extends` chain. Walks the chain transitively (cycle-guarded), since OAuth
+	 * credentials often extend a vendor intermediate (e.g. `atlassianOAuth2Api`)
+	 * rather than a base type directly.
+	 */
+	private extendsProxyAuthBaseType(credType: ICredentialType, seen = new Set<string>()): boolean {
+		if (!Array.isArray(credType.extends)) return false;
+
+		return credType.extends.some((parentName) => {
+			if (['oAuth2Api', 'googleOAuth2Api', 'oAuth1Api'].includes(parentName)) return true;
+			if (seen.has(parentName)) return false;
+			seen.add(parentName);
+
+			const parent = this.types.credentials.find((t) => t.name === parentName);
+			return parent !== undefined && this.extendsProxyAuthBaseType(parent, seen);
 		});
 	}