feat: Add ability to fetch step from data layer

[awilfox]

This is useful for pulling message metadata from an on_feedback callback, for instance.

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Summary by cubic

Add get_step to the data layer to fetch a step by ID with its associated feedback. This enables pulling message metadata in on_feedback callbacks.

• New Features
  • chainlit_data_layer.get_step: joins Feedback and returns a StepDict or None.
  • sql_alchemy.get_step: mirrors behavior, maps fields, respects showInput, and returns optional FeedbackDict.
  • No schema changes; read-only queries only.

^{Written for commit 32f5d82. Summary will update automatically on new commits.}

[cubic-dev-ai]

1 issue found across 2 files

Prompt for AI agents (all 1 issues)

Check if these issues are valid — if so, understand the root cause of each and fix them.


<file name="backend/chainlit/data/sql_alchemy.py">

<violation number="1" location="backend/chainlit/data/sql_alchemy.py:451">
P1: Missing empty list check before accessing `steps_feedbacks[0]`. If the step doesn&#39;t exist, the query returns an empty list and this will raise an `IndexError`. Follow the existing pattern used elsewhere in this file (e.g., `get_user`, `get_element`).</violation>
</file>

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[cubic-dev-ai]

P1: Missing empty list check before accessing steps_feedbacks[0]. If the step doesn't exist, the query returns an empty list and this will raise an IndexError. Follow the existing pattern used elsewhere in this file (e.g., get_user, get_element).

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At backend/chainlit/data/sql_alchemy.py, line 451:

<comment>Missing empty list check before accessing `steps_feedbacks[0]`. If the step doesn&#39;t exist, the query returns an empty list and this will raise an `IndexError`. Follow the existing pattern used elsewhere in this file (e.g., `get_user`, `get_element`).</comment>

<file context>
@@ -415,6 +415,83 @@ async def delete_step(self, step_id: str):
+            query=steps_feedbacks_query, parameters={&quot;step_id&quot;: step_id}
+        )
+
+        if not isinstance(steps_feedbacks, list):
+            return None
+
</file context>

Suggested change

	if not isinstance(steps_feedbacks, list):
	if not isinstance(steps_feedbacks, list) or not steps_feedbacks:

✅ Addressed in abbdfa9

[awilfox]

v2:

• Fixed ruff and mypy findings on the SQL Alchemy change. (Sorry; forgot to run them again locally after changing it a bit.)