fix: Do Not Mutate Config for Redacted Retries (#597)

* feat: Lazily load `https-proxy-agent`

* feat: Lazily load `https-proxy-agent`

* fix: Do Not Mutate Config for Redacted Retries

* fix: Do Not Mutate Config for Redacted Retries

* chore: remove note

* chore: Remove extraneous

src/common.ts

@@ -15,6 +15,7 @@ import {Agent} from 'http';
 import {URL} from 'url';
 
 import {pkg} from './util';
+import extend from 'extend';
 
 /**
  * Support `instanceof` operator for `GaxiosError`s in different versions of this library.
@@ -81,9 +82,19 @@ export class GaxiosError<T = any> extends Error {
   ) {
     super(message);
 
+    // deep-copy config as we do not want to mutate
+    // the existing config for future retries/use
+    this.config = extend(true, {}, config);
+    if (this.response) {
+      this.response.config = extend(true, {}, this.response.config);
+    }
+
     if (this.response) {
       try {
-        this.response.data = translateData(config.responseType, response?.data);
+        this.response.data = translateData(
+          this.config.responseType,
+          this.response?.data
+        );
       } catch {
         // best effort - don't throw an error within an error
         // we could set `this.response.config.responseType = 'unknown'`, but
@@ -98,22 +109,10 @@ export class GaxiosError<T = any> extends Error {
     }
 
     if (config.errorRedactor) {
-      const errorRedactor = config.errorRedactor<T>;
-
-      // shallow-copy config for redaction as we do not want
-      // future requests to have redacted information
-      this.config = {...config};
-      if (this.response) {
-        // copy response's config, as it may be recursively redacted
-        this.response = {...this.response, config: {...this.response.config}};
-      }
-
-      const results = errorRedactor({config, response});
-      this.config = {...config, ...results.config};
-
-      if (this.response) {
-        this.response = {...this.response, ...results.response, config};
-      }
+      config.errorRedactor<T>({
+        config: this.config,
+        response: this.response,
+      });
     }
   }
 }

src/gaxios.ts

@@ -73,8 +73,10 @@ function loadProxy() {
   if (proxy) {
     HttpsProxyAgent = httpsProxyAgent;
   }
+
   return proxy;
 }
+
 loadProxy();
 
 function skipProxy(url: string) {
@@ -186,7 +188,12 @@ export class Gaxios {
       if (shouldRetry && config) {
         err.config.retryConfig!.currentRetryAttempt =
           config.retryConfig!.currentRetryAttempt;
-        return this._request<T>(err.config);
+
+        // The error's config could be redacted - therefore we only want to
+        // copy the retry state over to the existing config
+        opts.retryConfig = err.config?.retryConfig;
+
+        return this._request<T>(opts);
       }
       throw err;
     }

test/test.getch.ts

@@ -713,6 +713,7 @@ describe('🎏 data handling', () => {
       body: 'grant_type=somesensitivedata&assertion=somesensitivedata',
     };
 
+    // simulate JSON response
     const responseHeaders = {
       ...config.headers,
       'content-type': 'application/json',
@@ -725,16 +726,22 @@ describe('🎏 data handling', () => {
       .reply(404, response, responseHeaders);
 
     const instance = new Gaxios(JSON.parse(JSON.stringify(config)));
+    const requestConfig: GaxiosOptions = {
+      url: customURL.toString(),
+      method: 'POST',
+    };
+    const requestConfigCopy = JSON.parse(JSON.stringify({...requestConfig}));
 
     try {
-      await instance.request({url: customURL.toString(), method: 'POST'});
+      await instance.request(requestConfig);
 
       throw new Error('Expected a GaxiosError');
     } catch (e) {
       assert(e instanceof GaxiosError);
 
       // config should not be mutated
       assert.deepStrictEqual(instance.defaults, config);
+      assert.deepStrictEqual(requestConfig, requestConfigCopy);
       assert.notStrictEqual(e.config, config);
 
       // config redactions - headers