Handle client level header size validation response before sending to server

.github/workflows/pull-request.yml

@@ -6,5 +6,5 @@ jobs:
   call_workflow:
     name: Run PR Build Workflow
     if: ${{ github.repository_owner == 'ballerina-platform' }}
-    uses: ballerina-platform/ballerina-standard-library/.github/workflows/pull-request-build-template.yml@main
+    uses: ballerina-platform/ballerina-standard-library/.github/workflows/pull-request-build-template.yml@dilanSachi-patch-1
     secrets: inherit

ballerina-tests/http2-tests/tests/http2_configuration_request_limit_config_test.bal

@@ -145,28 +145,33 @@ function testHttp2ValidHeaderLength() returns error? {
 }
 
 //Tests the behaviour when header size is greater than the configured threshold
-// TODO: Enable after fixing this issue : https://github.com/ballerina-platform/ballerina-standard-library/issues/3963
-@test:Config {
-    enable: false
-}
+@test:Config {}
 function testHttp2InvalidHeaderLength() returns error? {
     http:Client limitClient = check new ("http://localhost:" + http2RequestLimitsTestPort3.toString(),
         http2Settings = {http2PriorKnowledge: true});
-    http:Response response = check limitClient->get("/lowRequestHeaderLimit/invalidHeaderSize", {"X-Test": getLargeHeader()});
+    http:Response|http:Error response = limitClient->get("/lowRequestHeaderLimit/invalidHeaderSize", {"X-Test": getLargeHeader()});
     //431 Request Header Fields Too Large
-    test:assertEquals(response.statusCode, 431, msg = "Found unexpected output");
+    if response is http:Error {
+        test:assertTrue(response is http:ClientError);
+        test:assertEquals(response.message(), "Header size exceeded max allowed size (600)");
+    } else {
+        test:assertEquals(response.statusCode, 431, msg = "Found unexpected output");
+    }
 }
 
 // Tests the fallback behaviour when header size is greater than the configured http2 service
 // TODO: Enable after fixing this issue : https://github.com/ballerina-platform/ballerina-standard-library/issues/3963
-@test:Config {
-    enable: false
-}
+@test:Config {}
 function testHttp2Http2ServiceInvalidHeaderLength() returns error? {
     http:Client limitClient = check new ("http://localhost:" + requestLimitsTestPort5.toString(),
         http2Settings = {http2PriorKnowledge: true});
-    http:Response response = check limitClient->get("/http2service/invalidHeaderSize", {"X-Test": getLargeHeader()});
-    test:assertEquals(response.statusCode, 431, msg = "Found unexpected output");
+    http:Response|http:Error response = limitClient->get("/http2service/invalidHeaderSize", {"X-Test": getLargeHeader()});
+    if response is http:Error {
+        test:assertTrue(response is http:ClientError);
+        test:assertEquals(response.message(), "Header size exceeded max allowed size (850)");
+    } else {
+        test:assertEquals(response.statusCode, 431, msg = "Found unexpected output");
+    }
 }
 
 //Tests the behaviour when payload size is greater than the configured threshold

native/src/main/java/io/ballerina/stdlib/http/transport/contractimpl/common/states/Http2StateUtil.java

@@ -43,6 +43,7 @@
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelFutureListener;
 import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelPromise;
 import io.netty.handler.codec.http.DefaultLastHttpContent;
 import io.netty.handler.codec.http.HttpContent;
 import io.netty.handler.codec.http.HttpHeaderNames;
@@ -320,9 +321,13 @@ public static void writeHttp2Headers(ChannelHandlerContext ctx, OutboundMsgHolde
                 return;
             }
         }
-
-        encoder.writeHeaders(ctx, streamId, http2Headers, dependencyId, weight, false, 0, endStream,
-                             ctx.newPromise());
+        ChannelPromise promise = ctx.newPromise();
+        encoder.writeHeaders(ctx, streamId, http2Headers, dependencyId, weight, false, 0, endStream, promise);
+        promise.addListener((ChannelFutureListener) channelFuture -> {
+            if (!channelFuture.isSuccess()) {
+                outboundMsgHolder.getResponseFuture().notifyHttpListener(channelFuture.cause());
+            }
+        });
         encoder.flowController().writePendingBytes();
         ctx.flush();