Fix gemma chat template #4280
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Fix gemma chat template #4280
+51
−19
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Pull request overview
This PR aims to fix the gemma2 chat template to support models that forbid system roles in messages. The changes modify the HFChatTemplate class to gracefully handle such models by falling back to direct message processing when system role injection fails.
Changes:
- Modified
__init__to only verify user role support instead of storing role instruction attributes - Updated
messages2promptto use try-except fallback when models reject system roles - Changed
_role_instructionto return additional values (messages and prompt)
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 5 comments.
| File | Description |
|---|---|
| lmdeploy/model.py | Modified HFChatTemplate class to handle models that don't accept system roles with fallback logic |
| tests/test_lmdeploy/test_model.py | Added test for gemma-2 and gemma-3 models to verify chat template compatibility |
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add hf home to ut
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Motivation
gemma2 chat template cannot accept system role
Modification
model.py