Summary

Resolves #15059. This patch will fix a bug causing chat flow to be stuck in running state forever.

2025-04-08 21:11:50,654.654 ERROR [Dummy-147] [completion.py:138] - internal server error.
Traceback (most recent call last):
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/engine/base.py", line 1967, in _exec_single_context
    self.dialect.do_execute(
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/engine/default.py", line 941, in do_execute
    cursor.execute(statement, parameters)
psycopg2.errors.UniqueViolation: duplicate key value violates unique constraint "workflow_node_execution_pkey"
DETAIL:  Key (id)=(6021088b-72cd-46b4-a227-bed9733f5250) already exists.


The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/app/api/controllers/service_api/app/completion.py", line 115, in post
    response = AppGenerateService.generate(
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/api/services/app_generate_service.py", line 81, in generate
    generator=AdvancedChatAppGenerator().generate(
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/api/core/app/apps/advanced_chat/app_generator.py", line 160, in generate
    return self._generate(
           ^^^^^^^^^^^^^^^
  File "/app/api/core/app/apps/advanced_chat/app_generator.py", line 280, in _generate
    response = self._handle_advanced_chat_response(
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/api/core/app/apps/advanced_chat/app_generator.py", line 384, in _handle_advanced_chat_response
    return generate_task_pipeline.process()
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/api/core/app/apps/advanced_chat/generate_task_pipeline.py", line 154, in process
    return self._to_blocking_response(generator)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/api/core/app/apps/advanced_chat/generate_task_pipeline.py", line 161, in _to_blocking_response
    for stream_response in generator:
                           ^^^^^^^^^
  File "/app/api/core/app/apps/advanced_chat/generate_task_pipeline.py", line 224, in _wrapper_process_stream_response
    for response in self._process_stream_response(tts_publisher=tts_publisher, trace_manager=trace_manager):
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/api/core/app/apps/advanced_chat/generate_task_pipeline.py", line 368, in _process_stream_response
    session.commit()
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/orm/session.py", line 2028, in commit
    trans.commit(_to_root=True)
  File "<string>", line 2, in commit
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/orm/state_changes.py", line 139, in _go
    ret_value = fn(self, *arg, **kw)
                ^^^^^^^^^^^^^^^^^^^^
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/orm/session.py", line 1313, in commit
    self._prepare_impl()
  File "<string>", line 2, in _prepare_impl
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/orm/state_changes.py", line 139, in _go
    ret_value = fn(self, *arg, **kw)
                ^^^^^^^^^^^^^^^^^^^^
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/orm/session.py", line 1288, in _prepare_impl
    self.session.flush()
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/orm/session.py", line 4352, in flush
    self._flush(objects)
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/orm/session.py", line 4487, in _flush
    with util.safe_reraise():
         ^^^^^^^^^^^^^^^^^^^
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/util/langhelpers.py", line 146, in __exit__
    raise exc_value.with_traceback(exc_tb)
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/orm/session.py", line 4448, in _flush
    flush_context.execute()
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/orm/unitofwork.py", line 466, in execute
    rec.execute(self)
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/orm/unitofwork.py", line 642, in execute
    util.preloaded.orm_persistence.save_obj(
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/orm/persistence.py", line 93, in save_obj
    _emit_insert_statements(
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/orm/persistence.py", line 1048, in _emit_insert_statements
    result = connection.execute(
             ^^^^^^^^^^^^^^^^^^^
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/engine/base.py", line 1418, in execute
    return meth(
           ^^^^^
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/sql/elements.py", line 515, in _execute_on_connection
    return connection._execute_clauseelement(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/engine/base.py", line 1640, in _execute_clauseelement
    ret = self._execute_context(
          ^^^^^^^^^^^^^^^^^^^^^^
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/engine/base.py", line 1846, in _execute_context
    return self._exec_single_context(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/engine/base.py", line 1986, in _exec_single_context
    self._handle_dbapi_exception(
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/engine/base.py", line 2355, in _handle_dbapi_exception
    raise sqlalchemy_exception.with_traceback(exc_info[2]) from e
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/engine/base.py", line 1967, in _exec_single_context
    self.dialect.do_execute(
  File "/app/api/.venv/lib/python3.12/site-packages/sqlalchemy/engine/default.py", line 941, in do_execute
    cursor.execute(statement, parameters)
sqlalchemy.exc.IntegrityError: (psycopg2.errors.UniqueViolation) duplicate key value violates unique constraint "workflow_node_execution_pkey"
DETAIL:  Key (id)=(6021088b-72cd-46b4-a227-bed9733f5250) already exists.

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Checklist

[!IMPORTANT]
Please review the checklist below before submitting your pull request.

• [ ] This change requires a documentation update, included: Dify Document
• [x] I understand that this PR may be closed in case there was no previous discussion or issues. (This doesn't apply to typos!)
• [x] I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• [x] I've updated the documentation accordingly.
• [x] I ran dev/reformat(backend) and cd web && npx lint-staged(frontend) to appease the lint gods