fix: fall back to HF for Mistral3 VLMs with non-Mistral4 text backbone#1557
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fix: fall back to HF for Mistral3 VLMs with non-Mistral4 text backbone#1557
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The custom Mistral3ForConditionalGeneration model (added for Mistral4 MoE+MLA text backbones) was intercepting all models with that HF architecture, including Devstral-Small which uses a dense Ministral3 text backbone. This caused an AttributeError on `moe_intermediate_size`. Add a `supports_config` classmethod that custom model classes can define to opt out for incompatible configs. The registry's new `resolve_custom_model_cls` method checks this before returning a custom class, falling back to HF's native implementation when unsupported. Signed-off-by: HuiyingLi <willwin.lee@gmail.com> Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> Signed-off-by: HuiyingLi <willwin.lee@gmail.com>
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Mar 17, 2026
linnanwang
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Apr 24, 2026
#1557) The custom Mistral3ForConditionalGeneration model (added for Mistral4 MoE+MLA text backbones) was intercepting all models with that HF architecture, including Devstral-Small which uses a dense Ministral3 text backbone. This caused an AttributeError on `moe_intermediate_size`. Add a `supports_config` classmethod that custom model classes can define to opt out for incompatible configs. The registry's new `resolve_custom_model_cls` method checks this before returning a custom class, falling back to HF's native implementation when unsupported. Signed-off-by: HuiyingLi <willwin.lee@gmail.com> Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Summary
Mistral3ForConditionalGenerationmodel (for Mistral4 MoE+MLA) was intercepting all models with that HF architecture, including Devstral-Small which uses a dense Ministral3 text backbone, causingAttributeError: 'Ministral3Config' object has no attribute 'moe_intermediate_size'supports_configclassmethod toMistral3ForConditionalGenerationthat returnsFalsefor non-Mistral4 text configsresolve_custom_model_clsto_ModelRegistrythat checkssupports_configbefore returning a custom model class, falling back to HF's native implementation when unsupportedresolve_custom_model_cls(5) andsupports_config(4)Test plan
resolve_custom_model_clswith: found/not-found/supports-true/supports-false/config-passthroughsupports_configwith: mistral4-text/non-mistral4-text/no-text-config/no-model-typeruff checkandruff formatpass on all changed files🤖 Generated with Claude Code