QPACK: Don't update known received count when stream is cancelled.

src/main/java/io/netty/incubator/codec/http3/QpackEncoder.java

@@ -156,7 +156,7 @@ void sectionAcknowledgment(long streamId) throws QpackException {
             throw INVALID_SECTION_ACKNOWLEDGMENT;
         }
 
-        dynamicTableIndices.forEach(dynamicTable::acknowledgeInsertCount);
+        dynamicTableIndices.forEach(dynamicTable::acknowledgeInsertCountOnAck);
     }
 
     /**
@@ -179,7 +179,7 @@ void streamCancellation(long streamId) throws QpackException {
                 if (dynamicTableIndices == null) {
                     break;
                 }
-                dynamicTableIndices.forEach(dynamicTable::acknowledgeInsertCount);
+                dynamicTableIndices.forEach(dynamicTable::acknowledgeInsertCountOnCancellation);
             }
         }
     }

src/main/java/io/netty/incubator/codec/http3/QpackEncoderDynamicTable.java

@@ -166,15 +166,31 @@ int add(CharSequence name, CharSequence value, long headerSize) {
      * @param entryIndex For the entry corresponding to the {@link #insertCount()}.
      * @throws QpackException If the count is invalid.
      */
-    void acknowledgeInsertCount(int entryIndex) throws QpackException {
+    void acknowledgeInsertCountOnAck(int entryIndex) throws QpackException {
+        acknowledgeInsertCount(entryIndex, true);
+    }
+
+    /**
+     * Callback when a header block which had a {@link #insertCount()}} greater than {@code 0} is still not processed
+     * and the stream is <a href="https://www.rfc-editor.org/rfc/rfc9204.html#name-stream-cancellation">cancelled</a>
+     * by the decoder.
+     *
+     * @param entryIndex For the entry corresponding to the {@link #insertCount()}.
+     * @throws QpackException If the count is invalid.
+     */
+    void acknowledgeInsertCountOnCancellation(int entryIndex) throws QpackException {
+        acknowledgeInsertCount(entryIndex, false);
+    }
+
+    private void acknowledgeInsertCount(int entryIndex, boolean updateKnownReceived) throws QpackException {
         if (entryIndex < 0) {
             throw INVALID_REQUIRED_INSERT_COUNT_INCREMENT;
         }
         for (HeaderEntry e = head.next; e != null; e = e.next) {
             if (e.index == entryIndex) {
                 assert e.refCount > 0;
                 e.refCount--;
-                if (e.index > knownReceived.index) {
+                if (updateKnownReceived && e.index > knownReceived.index) {
                     // https://www.rfc-editor.org/rfc/rfc9204.html#name-known-received-count
                     // If the Required Insert Count of the acknowledged field section is greater than the current Known
                     // Received Count, Known Received Count is updated to that Required Insert Count value.

src/test/java/io/netty/incubator/codec/http3/QpackEncoderDynamicTableTest.java

@@ -161,7 +161,7 @@ public void sectionAck() throws Exception {
 
         final int idx = addAndValidateHeader(table, fooBarHeader);
         table.addReferenceToEntry(fooBarHeader.name, fooBarHeader.value, idx);
-        table.acknowledgeInsertCount(idx);
+        table.acknowledgeInsertCountOnAck(idx);
 
         assertThat("Unexpected known received count.", table.encodedKnownReceivedCount(), is(2));
     }
@@ -176,10 +176,10 @@ public void sectionAckOutOfOrder() throws Exception {
         final int idx2 = addAndValidateHeader(table, fooBarHeader);
         table.addReferenceToEntry(fooBarHeader.name, fooBarHeader.value, idx2);
 
-        table.acknowledgeInsertCount(idx2);
+        table.acknowledgeInsertCountOnAck(idx2);
         assertThat("Unexpected known received count.", table.encodedKnownReceivedCount(), is(3));
 
-        table.acknowledgeInsertCount(idx1);
+        table.acknowledgeInsertCountOnAck(idx1);
         assertThat("Unexpected known received count.", table.encodedKnownReceivedCount(), is(3)); // already acked
     }
 
@@ -192,12 +192,12 @@ public void multipleReferences() throws Exception {
         table.addReferenceToEntry(fooBar3Header.name, fooBar3Header.value, idx1);
         table.addReferenceToEntry(fooBar3Header.name, fooBar3Header.value, idx1);
 
-        table.acknowledgeInsertCount(idx1);
+        table.acknowledgeInsertCountOnAck(idx1);
 
         // first entry still active
         assertThat("Header added", addHeader(table, fooBar2Header), lessThan(0));
 
-        table.acknowledgeInsertCount(idx1);
+        table.acknowledgeInsertCountOnAck(idx1);
         verifyTableEmpty(table);
         addAndValidateHeader(table, fooBarHeader);
     }
@@ -229,7 +229,7 @@ private int addAndValidateHeader(QpackEncoderDynamicTable table, QpackHeaderFiel
     private int addValidateAndAckHeader(QpackEncoderDynamicTable table, QpackHeaderField header) throws Exception {
         final int addedIdx = addAndValidateHeader(table, header);
         table.addReferenceToEntry(header.name, header.value, addedIdx);
-        table.acknowledgeInsertCount(addedIdx);
+        table.acknowledgeInsertCountOnAck(addedIdx);
         return addedIdx;
     }