Hacktoberfest 2026: the issues maintainers tagged for October, open and beginner-friendly. Browse Hacktoberfest issues

BUG: MemoryInterface.get_request_from_response fails with IndexError for non-zero starting sequence or sequence gaps

Open
  • Is something wrong?
#3,189 0 comments 0 reactions 0 assignees View on GitHub

Maintainers usually reply within 2 days

@RohithPariki is already working on this.

Since Oct 13, 2026.

  • #3190 by @RohithPariki — open

Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
25/100
Issue type
Bug
Clarity
Clearly specified
Activity status
Active
Tech stack
python
Domain
databases

Research direction

The bug is in _execute_get_request_from_response in pyrit/memory/memory_interface.py, which indexes the conversation list by response.sequence - 1. Read _execute_get_conversation_messages to see how messages are ordered, then reproduce with the SQLite script in the issue. Pull request #3190 is already open against this issue, so check it before starting a new fix. Done means the method returns the message with the closest lower sequence, or raises a clear error when none exists.

Written by the indexing model from the issue text.

Description

Describe the bug

In pyrit/memory/memory_interface.py, MemoryInterface._execute_get_request_from_response retrieves the request that produced a given assistant response:

    def _execute_get_request_from_response(self, *, response: Message) -> Message:
        if response.api_role != "assistant":
            raise ValueError("The provided request is not a response (role must be 'assistant').")
        if response.sequence < 1:
            raise ValueError("The provided request does not have a preceding request (sequence < 1).")

        conversation = self._dispatch_memory_operation(
            "get_conversation_messages",
            self._execute_get_conversation_messages,
            conversation_id=response.conversation_id,
        )
        return conversation[response.sequence - 1]

The method treats response.sequence - 1 as a 0-based list index into conversation. However, get_conversation_messages returns messages ordered by sequence (sorted(conversation_by_sequence.keys())), where list index corresponds to sequence number only if the conversation started at sequence 0 and contains no sequence gaps.

Whenever:

  1. A conversation starts at a non-zero sequence (e.g. using starting_sequence in SeedPrompt.from_messages or SimulatedConversationAttack), or
  2. A conversation contains sequence gaps (e.g. after pruning or retries where pieces were deleted),

calling get_request_from_response (or get_request_from_response_async, or DecodingScorer which invokes this method) raises:
IndexError: list index out of range (or returns the wrong message if the index exists but does not align).

Steps/Code to Reproduce
import asyncio
from uuid import uuid4
from pyrit.memory import SQLiteMemory
from pyrit.models import MessagePiece

async def test_reproduce():
    memory = SQLiteMemory(db_path=":memory:")
    conversation_id = str(uuid4())

    # Create a conversation with starting_sequence=10
    pieces = [
        MessagePiece(
            role="user",
            original_value="What is the capital of France?",
            conversation_id=conversation_id,
            sequence=10,
        ),
        MessagePiece(
            role="assistant",
            original_value="Paris.",
            conversation_id=conversation_id,
            sequence=11,
        ),
    ]
    await memory.add_message_pieces_to_memory_async(message_pieces=pieces)

    conversation = await memory.get_conversation_messages_async(conversation_id=conversation_id)
    response = conversation[1]  # sequence=11

    # Attempt to retrieve the request that produced the response
    await memory.get_request_from_response_async(response=response)

asyncio.run(test_reproduce())
Expected Results

get_request_from_response_async returns the message immediately preceding the response in the conversation timeline (Message(role='user', sequence=10, ...)).

Actual Results
Traceback (most recent call last):
  ...
  File "pyrit/memory/memory_interface.py", line 3041, in _execute_get_request_from_response
    return conversation[response.sequence - 1]
           ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^
IndexError: list index out of range
Suggested Fix

Instead of assuming conversation index equals sequence - 1, locate the preceding message in conversation with sequence < response.sequence:

        conversation = self._dispatch_memory_operation(
            "get_conversation_messages",
            self._execute_get_conversation_messages,
            conversation_id=response.conversation_id,
        )
        preceding_messages = [msg for msg in conversation if msg.sequence < response.sequence]
        if not preceding_messages:
            raise ValueError(
                f"The provided request does not have a preceding request in conversation '{response.conversation_id}'."
            )
        return preceding_messages[-1]
Dominant language
Python
Stars
4.6k
Forks
944
Avg merge
2d 17h
Merged PRs (30d)
328

Getting set up

Open in Codespaces

Starts the project's dev container in your browser, under your own GitHub account.

  • No Dockerfile or Docker Compose file
  • Has a pull request template
  • No contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

More from microsoft/PyRIT

All issues in microsoft/PyRIT

Similar issues

More Python issues

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.