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fix: ChatHistory: preserve empty tool results with tool_call_id - #14480
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_prepare_for_add() checked 'content' (truthy check) when deciding to
create FunctionResultContent for a TOOL message. An empty string content
is falsy, so add_tool_message('', tool_call_id='...') silently dropped
the tool_call_id and created an invalid message with no items.
Change 'content' to 'content is not None' so an empty string result
is accepted and the FunctionResultContent is created with the call_id.
Fixes microsoft#14359.
Wu Shuwen (dajiaohuang)
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Copilot review overview
🟡 Changes recommended
Add the requested regression test for empty tool results and serialization.
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Review effort: Lite
Findings: 1
Open (1)
What changed in this PR
Fixes ChatHistory so empty-string tool results preserve their tool_call_id and serialize correctly.
Changes:
- Accepts non-
Nonetool content, including empty strings. - Preserves
FunctionResultContentfor empty tool results.
| File | Summary |
|---|---|
python/semantic_kernel/contents/chat_history.py |
Preserves empty tool results and IDs; add a regression test covering empty results and to_dict() serialization. |
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| kwargs["role"] = role | ||
|
|
||
| if role == AuthorRole.TOOL and content and not items: | ||
| if role == AuthorRole.TOOL and content is not None and not items: |
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Description
_prepare_for_add() checked 'content' (truthy check) when deciding to create FunctionResultContent for a TOOL message. An empty string content is falsy, so add_tool_message('', tool_call_id='...') silently dropped the tool_call_id and created an invalid message with no items.
Reproduction
Fix
Change 'content' to 'content is not None' so an empty string result is accepted and the FunctionResultContent is created with the call_id preserved.
Fixes #14359.