Add resume_saxerror tests and fix async iterator SAX error handling

- Add test/feeds/saxerror.xml: RSS feed with a bare & that triggers a SAX
  error in strict mode, used to demonstrate both resume behaviours
- In handleSaxError, set/clear a _isSaxError flag around emit() so that
  listeners can distinguish SAX errors from fatal errors synchronously
- In Symbol.asyncIterator, ignore resumable SAX errors in onError (check
  _isSaxError && resume_saxerror) so that parsing continues rather than
  throwing; fatal errors (resume_saxerror: false, or non-SAX errors) still
  propagate as exceptions
- Tests use write()+end() via setImmediate instead of pipe(): readable-stream
  v2 calls unpipe() when the destination emits 'error', which prevents _flush
  from ever being called and the stream from ending

https://claude.ai/code/session_01Rx48d2xCMjtzmoynPwet77

Author: claude

lib/feedparser/index.js

@@ -131,7 +131,9 @@ FeedParser.prototype.handleEnd = function (){
 
 /** @this {FeedParserInstance} */
 FeedParser.prototype.handleSaxError = function (e) {
+  this._isSaxError = true;
   this.emit('error', e);
+  this._isSaxError = false;
   if (this.options.resume_saxerror) {
     this.resumeSaxError();
   }
@@ -1239,6 +1241,7 @@ FeedParser.prototype._flush = function (done) {
 
 /** @this {FeedParserInstance} */
 FeedParser.prototype[Symbol.asyncIterator] = async function* () {
+  var self = this;
   var resolve = null;
   var error = null;
   var ended = false;
@@ -1251,6 +1254,9 @@ FeedParser.prototype[Symbol.asyncIterator] = async function* () {
     if (resolve) { resolve(); resolve = null; }
   }
   function onError(err) {
+    if (self._isSaxError && self.options.resume_saxerror) {
+      return; // Non-fatal: parsing will resume automatically
+    }
     error = err;
     if (resolve) { resolve(); resolve = null; }
   }

test/examples.js

@@ -15,6 +15,43 @@ describe('examples', function () {
     assert.equal(items.length, 4);
   });
 
+  describe('resume_saxerror', function () {
+    var content = fs.readFileSync(__dirname + '/feeds/saxerror.xml');
+
+    // pipe() breaks when 'error' fires on the destination (readable-stream v2
+    // behaviour), so we write directly and schedule it after the for-await loop
+    // has started (i.e. after the async iterator has registered its listeners).
+    function writeAsync(feedparser) {
+      setImmediate(function () { feedparser.write(content); feedparser.end(); });
+    }
+
+    it('should continue iterating past SAX errors by default (resume_saxerror: true)', async function () {
+      var feedparser = new FeedParser({ strict: true });
+      var items = [];
+      writeAsync(feedparser);
+
+      for await (const item of feedparser) {
+        items.push(item);
+      }
+
+      assert.ok(items.length > 0);
+    });
+
+    it('should throw on SAX errors when resume_saxerror is false', async function () {
+      var feedparser = new FeedParser({ strict: true, resume_saxerror: false });
+      writeAsync(feedparser);
+
+      var caught = null;
+      try {
+        for await (const item of feedparser) {} // eslint-disable-line no-unused-vars
+      } catch (err) {
+        caught = err;
+      }
+
+      assert.ok(caught instanceof Error);
+    });
+  });
+
   it('should surface errors via try/catch when using async iterator', async function () {
     var feedparser = new FeedParser();
     var feed = __dirname + '/feeds/notafeed.html';

test/feeds/saxerror.xml

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<rss version="2.0">
+  <channel>
+    <title>Test Feed</title>
+    <link>http://example.com</link>
+    <description>Feed for testing SAX error recovery</description>
+    <item>
+      <title>Item 1</title>
+      <link>http://example.com/item/1</link>
+      <guid>http://example.com/item/1</guid>
+    </item>
+    <item>
+      <title>Item with invalid & bare ampersand</title>
+      <link>http://example.com/item/2</link>
+      <guid>http://example.com/item/2</guid>
+    </item>
+    <item>
+      <title>Item 3</title>
+      <link>http://example.com/item/3</link>
+      <guid>http://example.com/item/3</guid>
+    </item>
+  </channel>
+</rss>