huggingface input_error ai_generated true

UserWarning: We strongly recommend passing in an `attention_mask` since your input_ids may be padded. See https://huggingface.co/docs/transformers/troubleshooting

ID: huggingface/attention-mask-warning

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90%Fix Rate
92%Confidence
3Evidence
2023-01-01First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
any active — — —

Root Cause

Model called without attention mask on padded inputs. Padding tokens will be attended to, producing wrong outputs.

generic

Workarounds

  1. 95% success Always pass attention_mask from tokenizer output 
    inputs = tokenizer(text, padding=True, return_tensors='pt'); outputs = model(**inputs)  # attention_mask included automatically

    Sources: https://huggingface.co/docs/transformers/

  2. 92% success Use tokenizer with padding=True and return_attention_mask=True 
    tokenizer(texts, padding=True, truncation=True, return_attention_mask=True, return_tensors='pt')
  3. 85% success Set pad_token if tokenizer does not have one 
    tokenizer.pad_token = tokenizer.eos_token  # required for models like GPT-2 that lack a pad token

Dead Ends

Common approaches that don't work:

  1. Suppress the warning with warnings.filterwarnings 90% fail

    Suppressing the warning does not fix the bug. The model will attend to padding tokens and produce degraded outputs.

  2. Pad inputs but skip attention mask assuming the model ignores padding 85% fail

    Most transformer models attend to all tokens by default. Without attention mask, padding tokens corrupt the attention computation.