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fix(binding-mcp-kafka): stop reset_offsets hanging after a stale stage END #2540

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Merged
jfallows merged 4 commits into from
Sep 4, 2026
Merged

fix(binding-mcp-kafka): stop reset_offsets hanging after a stale stage END #2540

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7e55acf
test(binding-kafka): cover bare offset-commit and chained api-request…
claude Sep 4, 2026
28a9fe5
fix(binding-mcp-kafka): stop reset_offsets hanging after a stale stag…
claude Sep 4, 2026
e4f78f2
Merge remote-tracking branch 'origin/develop' into claude/zilla-issue…
claude Sep 4, 2026
8d73435
test(binding-mcp-kafka): add end-to-end regression coverage for reset…
claude Sep 4, 2026
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52 changes: 52 additions & 0 deletions ...st/java/io/aklivity/zilla/runtime/binding/kafka/internal/stream/ClientOffsetCommitIT.java
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Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,8 @@ public class ClientOffsetCommitIT
.directory("target/zilla-itests")
.countersBufferCapacity(8192)
.configurationRoot("io/aklivity/zilla/specs/binding/kafka/config")
.configure("zilla.binding.kafka.client.connection.pool", "false")
.configure("zilla.binding.kafka.client.api.versions", "false")
.external("net0")
.clean();

Expand Down Expand Up @@ -87,4 +89,54 @@ public void shouldHandleOffsetCommitError() throws Exception
{
k3po.finish();
}

@Test
@Configuration("client.yaml")
@Specification({
"${app}/bare.commit/client",
"${net}/bare.commit/server"})
public void shouldCommitBareOffset() throws Exception
{
k3po.finish();
}

@Test
@Configuration("client.yaml")
@Specification({
"${app}/reset.offsets.dead/client",
"${net}/reset.offsets.dead/server"})
public void shouldResetOffsetsForDeadGroup() throws Exception
{
k3po.finish();
}

@Test
@Configuration("client.yaml")
@Specification({
"${app}/find.then.describe/client",
"${net}/find.then.describe/server"})
public void shouldChainFindCoordinatorThenDescribeGroups() throws Exception
{
k3po.finish();
}

@Test
@Configuration("client.yaml")
@Specification({
"${app}/find.coordinator.only/client",
"${net}/find.coordinator.only/server"})
public void shouldFindCoordinatorOnly() throws Exception
{
k3po.finish();
}

@Test
@Configuration("client.yaml")
@Specification({
"${app}/find.then.describe.no.wait/client",
"${net}/find.then.describe/server"})
public void shouldChainFindCoordinatorThenDescribeGroupsNoWait() throws Exception
{
k3po.finish();
}
}
15 changes: 11 additions & 4 deletions ...ava/io/aklivity/zilla/runtime/binding/mcp/kafka/internal/stream/McpKafkaProxyFactory.java
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Original file line number Diff line number Diff line change
Expand Up @@ -9041,16 +9041,23 @@ private void advanceToOffsetCommit(
traceId, authorization, affinity, kafkaBeginEx);
}

/**
* Only the reply of the stage currently in flight closes the MCP reply; the previous stage's
* reply END arrives after {@link #advanceToOffsetCommit} has already opened the next stream.
*/
private void onKafkaEnd(
EndFW end)
{
final long traceId = end.traceId();

state = McpKafkaState.closedReply(state);

if (stage == STAGE_OFFSET_COMMIT && mcpBegun)
if (end.streamId() == kafkaReplyId)
{
peer.doMcpEnd(traceId);
state = McpKafkaState.closedReply(state);

if (stage == STAGE_OFFSET_COMMIT && mcpBegun)
{
peer.doMcpEnd(traceId);
}
}
}

Expand Down
10 changes: 10 additions & 0 deletions ...st/java/io/aklivity/zilla/runtime/binding/mcp/kafka/internal/stream/McpKafkaClientIT.java
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Original file line number Diff line number Diff line change
Expand Up @@ -365,6 +365,16 @@ public void shouldResetOffsetsCoordinatorNotFound() throws Exception
k3po.finish();
}

@Test
@Configuration("client.reset.offsets.yaml")
@Specification({
"${mcp}/reset.offsets.dead/client",
"${kafka}/reset.offsets.dead/server"})
public void shouldResetOffsetsForDeadGroup() throws Exception
{
k3po.finish();
}

@Test
@Configuration("client.describe.consumer.group.lag.yaml")
@Specification({
Expand Down
45 changes: 45 additions & 0 deletions ...livity/zilla/specs/binding/kafka/streams/application/offset.commit/bare.commit/client.rpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,45 @@
#
# Copyright 2021-2026 Aklivity Inc.
#
# Aklivity licenses this file to you under the Apache License,
# version 2.0 (the "License"); you may not use this file except in compliance
# with the License. You may obtain a copy of the License at:
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
#

connect "zilla://streams/app0"
option zilla:window 8192
option zilla:transmission "half-duplex"

write zilla:begin.ext ${kafka:beginEx()
.typeId(zilla:id("kafka"))
.offsetCommit()
.groupId("orders-analytics")
.memberId("")
.instanceId("")
.host("broker1.example.com")
.port(9092)
.build()
.build()}

connected

write zilla:data.ext ${kafka:dataEx()
.typeId(zilla:id("kafka"))
.offsetCommit()
.topic("orders")
.progress(0, 100, "")
.generationId(-1)
.leaderEpoch(-1)
.build()
.build()}

write zilla:data.empty
write flush
57 changes: 57 additions & 0 deletions ...la/specs/binding/kafka/streams/application/offset.commit/find.coordinator.only/client.rpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,57 @@
#
# Copyright 2021-2026 Aklivity Inc.
#
# Aklivity licenses this file to you under the Apache License,
# version 2.0 (the "License"); you may not use this file except in compliance
# with the License. You may obtain a copy of the License at:
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
#

connect "zilla://streams/app0"
option zilla:window 8192
option zilla:transmission "half-duplex"
option zilla:byteorder "network"

write zilla:begin.ext ${kafka:beginEx()
.typeId(zilla:id("kafka"))
.apiRequest()
.length(12)
.api(10)
.version(3)
.clientId("zilla")
.build()
.build()}

connected

write [0x00] # request header tagged fields
[0x09] "my-group" # group id (key)
[0x00] # key type (group)
[0x00] # tagged fields

read zilla:begin.ext ${kafka:matchBeginEx()
.typeId(zilla:id("kafka"))
.apiResponse()
.length(25)
.version(3)
.build()
.build()}

read [0x00] # tagged fields
0 # throttle time ms
0s # error code
[0x00] # message (null)
1 # node id
[0x08] "broker1" # host
9092 # port
[0x00] # tagged fields

write close
read closed
107 changes: 107 additions & 0 deletions ...ecs/binding/kafka/streams/application/offset.commit/find.then.describe.no.wait/client.rpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,107 @@
#
# Copyright 2021-2026 Aklivity Inc.
#
# Aklivity licenses this file to you under the Apache License,
# version 2.0 (the "License"); you may not use this file except in compliance
# with the License. You may obtain a copy of the License at:
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
#

# Mirrors McpKafkaProxyFactory's KafkaApiResetOffsetsClient: it ends the
# FindCoordinator stream and opens the DescribeGroups stream in the same
# synchronous call, without waiting for the END to be acknowledged first.

connect "zilla://streams/app0"
option zilla:window 8192
option zilla:transmission "half-duplex"
option zilla:byteorder "network"

write zilla:begin.ext ${kafka:beginEx()
.typeId(zilla:id("kafka"))
.apiRequest()
.length(12)
.api(10)
.version(3)
.clientId("zilla")
.build()
.build()}

connected

write [0x00] # request header tagged fields
[0x09] "my-group" # group id (key)
[0x00] # key type (group)
[0x00] # tagged fields

read zilla:begin.ext ${kafka:matchBeginEx()
.typeId(zilla:id("kafka"))
.apiResponse()
.length(25)
.version(3)
.build()
.build()}

read [0x00] # tagged fields
0 # throttle time ms
0s # error code
[0x00] # message (null)
1 # node id
[0x08] "broker1" # host
9092 # port
[0x00] # tagged fields

write close

connect "zilla://streams/app0"
option zilla:window 8192
option zilla:transmission "half-duplex"
option zilla:byteorder "network"

write zilla:begin.ext ${kafka:beginEx()
.typeId(zilla:id("kafka"))
.apiRequest()
.length(13)
.api(15)
.version(5)
.clientId("zilla")
.build()
.build()}

connected

write [0x00] # request header tagged fields
[0x02] # group count
[0x09] "my-group" # group id
[0x00] # include authorized operations
[0x00] # tagged fields

read zilla:begin.ext ${kafka:matchBeginEx()
.typeId(zilla:id("kafka"))
.apiResponse()
.length(31)
.version(5)
.build()
.build()}

read [0x00] # tagged fields
0 # throttle time ms
[0x02] # groups
0s # error code
[0x09] "my-group" # group id
[0x05] "Dead" # group state (never had members)
[0x01] # protocol type (empty)
[0x01] # protocol data (empty)
[0x01] # members (none)
[0xff 0xff 0xff 0xff] # authorized operations (-1)
[0x00] # group tagged fields
[0x00] # tagged fields

write close
read closed
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