OIDC issuer behind a proxy cannot be accessed

app/server/lib/OIDCConfig.ts

@@ -182,7 +182,7 @@ export class OIDCConfig {
 
     this._redirectUrl = new URL(CALLBACK_URL, spHost).href;
     custom.setHttpOptionsDefaults({
-      agent: issuerUrl !== undefined ? proxyAgent(new URL(issuerUrl)) : undefined,
+      ...(issuerUrl !== undefined ? {agent: proxyAgent(new URL(issuerUrl))} : {}),
       ...(httpTimeout !== undefined ? {timeout: httpTimeout} : {}),
     });
     await this._initClient({ issuerUrl, clientId, clientSecret, extraMetadata });

test/server/lib/OIDCConfig.ts

@@ -197,7 +197,7 @@ describe('OIDCConfig', () => {
       [
         {
           itMsg: 'when omitted should not override openid-client default value',
-          expectedUserDefinedHttpOptions: {}
+          expectedUserDefinedHttpOptions: { agent: undefined }
         },
         {
           itMsg: 'should reject when the provided value is not a number',
@@ -213,6 +213,7 @@ describe('OIDCConfig', () => {
           },
           shouldSetTimeout: true,
           expectedUserDefinedHttpOptions: {
+            agent: undefined,
             timeout: 10000
           }
         },
@@ -222,6 +223,7 @@ describe('OIDCConfig', () => {
             GRIST_OIDC_SP_HTTP_TIMEOUT: '0',
           },
           expectedUserDefinedHttpOptions: {
+            agent: undefined,
             timeout: 0
           }
         }