unsloth/studio/backend/utils/datasets/chat_templates.py
DoubleMathew 797ae4cf40 mlx fixes
2026-05-07 12:43:40 -05:00

488 lines
18 KiB
Python

# SPDX-License-Identifier: AGPL-3.0-only
# Copyright 2026-present the Unsloth AI Inc. team. All rights reserved. See /studio/LICENSE.AGPL-3.0
"""
Chat template application utilities for dataset processing.
This module contains functions for applying chat templates to datasets
and generating dataset info summaries.
"""
import importlib.util
import os
import platform
from .format_detection import detect_dataset_format, detect_multimodal_dataset, detect_custom_format_heuristic
from .model_mappings import MODEL_TO_TEMPLATE_MAPPER
from loggers import get_logger
logger = get_logger(__name__)
DEFAULT_ALPACA_TEMPLATE = """Below is an instruction that describes a task, paired with an input that provides further context. Write a response that appropriately completes the request.
### Instruction:
{}
### Input:
{}
### Response:
{}"""
def _is_mlx_runtime() -> bool:
return (
os.environ.get("UNSLOTH_FORCE_GPU_PATH", "0") != "1"
and platform.system() == "Darwin"
and platform.machine() == "arm64"
and importlib.util.find_spec("mlx") is not None
)
def _fallback_apply_chat_template(convo) -> str:
parts = []
for message in convo or []:
role = message.get("role") or message.get("from") or "user"
content = message.get("content")
if content is None:
content = message.get("value", "")
if isinstance(content, list):
content = "\n".join(
str(part.get("text", part))
if isinstance(part, dict) else str(part)
for part in content
if not (isinstance(part, dict) and part.get("type") == "image")
)
parts.append(f"<|im_start|>{role}\n{content}<|im_end|>")
return "\n".join(parts)
def get_tokenizer_chat_template(tokenizer, model_name):
"""
Gets appropriate chat template for tokenizer based on model.
Uses Unsloth's get_chat_template if model is in the mapper.
Args:
tokenizer: HuggingFace tokenizer
model_name: Model class name (e.g., "Gemma3ForCausalLM")
Returns:
tokenizer: Tokenizer with appropriate chat template applied
"""
if _is_mlx_runtime():
return tokenizer
try:
from unsloth.chat_templates import get_chat_template
except ImportError:
# Unsloth not available, return tokenizer as-is
return tokenizer
# Normalize model_name to lowercase for matching
model_name_lower = model_name.lower()
# Check if model matches any template in mapper
matched_template = None
# Direct match in MODEL_TO_TEMPLATE_MAPPER
if model_name_lower in MODEL_TO_TEMPLATE_MAPPER:
matched_template = MODEL_TO_TEMPLATE_MAPPER[model_name_lower]
logger.info(f"📝 Applying Unsloth chat template: {matched_template}")
try:
tokenizer = get_chat_template(
tokenizer,
chat_template = matched_template,
)
except Exception as e:
logger.info(f"⚠️ Failed to apply Unsloth template '{matched_template}': {e}")
logger.info(f" Falling back to tokenizer's default chat template")
else:
# Check if tokenizer actually has a chat_template set
has_chat_template = (
hasattr(tokenizer, 'chat_template')
and tokenizer.chat_template is not None
)
if has_chat_template:
logger.info(f"📝 Using tokenizer's own chat template (no Unsloth template match)")
else:
# Base model with no chat template — apply default ChatML
logger.info(f"📝 No chat template found — applying default ChatML template (base model)")
try:
tokenizer = get_chat_template(
tokenizer,
chat_template = "chatml",
)
except Exception as e:
logger.info(f"⚠️ Failed to apply default ChatML template: {e}")
logger.info(f" Falling back to tokenizer as-is")
return tokenizer
def get_dataset_info_summary(dataset_info):
"""
Returns a human-readable summary for UI display.
"""
detected_format = dataset_info["detected_format"]
final_format = dataset_info["final_format"]
format_descriptions = {
"alpaca": "Alpaca format (instruction/input/output)",
"sharegpt": "ShareGPT format (needs standardization)",
"chatml_messages": "ChatML format (messages column) - OpenAI compatible",
"chatml_conversations": "ChatML format (conversations column) - HuggingFace standard",
"unknown": "Unknown format"
}
return {
"detected_format": detected_format,
"final_format": final_format,
"detected_description": format_descriptions.get(detected_format, "Unknown"),
"final_description": format_descriptions.get(final_format, "Unknown"),
"chat_column": dataset_info["chat_column"],
"is_standardized": dataset_info["is_standardized"],
"warnings": dataset_info.get("warnings", []),
"ready_for_training": dataset_info["is_standardized"] and final_format != "unknown"
}
def apply_chat_template_to_dataset(
dataset_info,
tokenizer,
model_name = None,
custom_prompt_template = None,
add_eos_token = False,
remove_bos_prefix = False,
custom_format_mapping = None,
auto_detect_mapping = True,
batch_size = 1000,
num_proc = None,
progress_callback = None,
):
"""
Applies chat template to dataset based on its format.
Args:
dataset_info: Output from format_dataset() with metadata
tokenizer: Tokenizer with chat template
custom_prompt_template: Optional string template for custom formatting
add_eos_token: If True, appends tokenizer.eos_token to each text
remove_bos_prefix: If True, removes '<bos>' prefix (for Gemma, etc.)
custom_format_mapping: Dict mapping custom columns to standard format
batch_size: Batch size for processing
num_proc: Number of processes
Returns:
dict with dataset, success status, warnings, and errors
"""
dataset = dataset_info["dataset"]
final_format = dataset_info["final_format"]
chat_column = dataset_info["chat_column"]
is_standardized = dataset_info["is_standardized"]
warnings = list(dataset_info.get("warnings", []))
errors = []
# Get EOS token if needed
eos_token = ""
if add_eos_token:
if hasattr(tokenizer, 'eos_token') and tokenizer.eos_token:
eos_token = tokenizer.eos_token
else:
warnings.append("add_eos_token=True but tokenizer has no eos_token")
# CUSTOM FORMAT MAPPING (for non-standard datasets)
if final_format == "unknown":
# Try auto-detection if no custom mapping provided
if custom_format_mapping is None and auto_detect_mapping:
# Check if format_dataset already tried and failed
if not dataset_info.get("auto_detection_attempted", False):
custom_format_mapping = detect_custom_format_heuristic(dataset)
if custom_format_mapping:
warnings.append(f"Auto-detected column mapping: {custom_format_mapping}")
else:
errors.append("Could not auto-detect format mapping")
return {
"dataset": dataset,
"success": False,
"warnings": warnings,
"errors": errors
}
else:
# Already failed once in format_dataset, don't retry
errors.append(
"Format remains unknown after detection attempts. "
"Please provide custom_format_mapping to specify column roles manually."
)
return {
"dataset": dataset,
"success": False,
"warnings": warnings,
"errors": errors
}
if custom_format_mapping:
warnings.append(f"Applying custom format mapping: {custom_format_mapping}")
is_user_provided = dataset_info.get("custom_format_mapping") is not None
def _apply_custom_mapping(examples):
conversations = []
num_examples = len(examples[list(examples.keys())[0]])
# Only preserve unmapped columns if auto-detected
preserved_columns = {}
if not is_user_provided:
all_columns = set(examples.keys())
mapped_columns = set(custom_format_mapping.keys())
non_mapped_columns = all_columns - mapped_columns
for col in non_mapped_columns:
preserved_columns[col] = examples[col]
for i in range(num_examples):
convo = []
role_order = ['system', 'user', 'assistant']
for target_role in role_order:
for col_name, role in custom_format_mapping.items():
if role == target_role and col_name in examples:
content = examples[col_name][i]
if is_user_provided:
# User explicitly mapped - include even if empty
convo.append({"role": role, "content": str(content) if content else ""})
else:
# Auto-detected - skip empty
if content and str(content).strip():
convo.append({"role": role, "content": str(content)})
conversations.append(convo)
result = {"conversations": conversations}
if not is_user_provided:
result.update(preserved_columns)
return result
try:
dataset = dataset.map(_apply_custom_mapping, batched = True, batch_size = batch_size)
# Update to use conversations format
final_format = "chatml_conversations"
chat_column = "conversations"
is_standardized = True
warnings.append("Successfully converted to ChatML format via custom mapping")
except Exception as e:
errors.append(f"Custom format mapping failed: {e}")
return {
"dataset": dataset,
"success": False,
"warnings": warnings,
"errors": errors
}
# ALPACA FORMAT
if final_format == "alpaca":
# Set alpaca chat template on tokenizer for saving (if not already set)
# This ensures the template is saved with the model for inference
if (
not _is_mlx_runtime()
and not (hasattr(tokenizer, 'chat_template') and tokenizer.chat_template)
):
try:
from unsloth.chat_templates import get_chat_template
tokenizer = get_chat_template(tokenizer, chat_template = "alpaca")
logger.info(f"📝 Set alpaca chat template on tokenizer for model saving")
except Exception as e:
logger.info(f"⚠️ Could not set alpaca template on tokenizer: {e}")
# Use custom template if provided
def _format_alpaca_custom(examples):
texts = []
for i in range(len(examples["instruction"])):
fields = {
"instruction": examples["instruction"][i],
"input": examples.get("input", [""] * len(examples["instruction"]))[i],
"output": examples["output"][i]
}
try:
text = DEFAULT_ALPACA_TEMPLATE.format(fields["instruction"], fields["input"], fields["output"])
text += eos_token
texts.append(text)
except KeyError as e:
errors.append(f"Custom template missing field: {e}")
texts.append("")
return {"text": texts}
formatted_fn = _format_alpaca_custom
try:
dataset_map_kwargs = {
'batched': True,
'batch_size': batch_size,
}
try:
from torch.utils.data import IterableDataset
_is_torch_iterable = isinstance(dataset, IterableDataset)
except ImportError:
_is_torch_iterable = False
if not _is_torch_iterable:
from utils.hardware import dataset_map_num_proc
if num_proc is None or type(num_proc) is not int:
num_proc = dataset_map_num_proc()
else:
num_proc = dataset_map_num_proc(num_proc)
dataset_map_kwargs['num_proc'] = num_proc
dataset_map_kwargs['desc'] = "Applying template to Alpaca format"
formatted_dataset = dataset.map(formatted_fn, **dataset_map_kwargs)
return {
"dataset": formatted_dataset,
"success": True,
"warnings": warnings,
"errors": errors
}
except Exception as e:
errors.append(f"Failed to format Alpaca dataset: {e}")
return {
"dataset": dataset,
"success": False,
"warnings": warnings,
"errors": errors
}
# CHATML FORMATS
elif final_format in ["chatml_messages", "chatml_conversations"]:
if not is_standardized:
warnings.append("Dataset may not be fully standardized")
# Apply Unsloth chat template if model matches
if model_name:
tokenizer = get_tokenizer_chat_template(tokenizer, model_name)
is_mlx_runtime = _is_mlx_runtime()
def _format_chatml(examples):
convos = examples[chat_column]
texts = []
for convo in convos:
try:
if is_mlx_runtime:
if (
hasattr(tokenizer, "apply_chat_template")
and getattr(tokenizer, "chat_template", None)
):
text = tokenizer.apply_chat_template(
convo,
tokenize = False,
add_generation_prompt = False
)
else:
text = _fallback_apply_chat_template(convo)
else:
text = tokenizer.apply_chat_template(
convo,
tokenize = False,
add_generation_prompt = False
)
if remove_bos_prefix:
text = text.removeprefix('<bos>')
text += eos_token
texts.append(text)
except Exception as e:
if len(texts) == 0:
warnings.append(f"Chat template failed: {e}")
texts.append("")
return {"text": texts}
try:
try:
from torch.utils.data import IterableDataset
_is_torch_iterable = isinstance(dataset, IterableDataset)
except ImportError:
_is_torch_iterable = False
dataset_map_kwargs = {
'batched': True,
'batch_size': batch_size,
}
if not _is_torch_iterable:
from utils.hardware import dataset_map_num_proc
if num_proc is None or type(num_proc) is not int:
num_proc = dataset_map_num_proc()
else:
num_proc = dataset_map_num_proc(num_proc)
dataset_map_kwargs['num_proc'] = num_proc
dataset_map_kwargs['desc'] = f"Applying chat template to {final_format}"
# Monitor tqdm progress from dataset.map() and relay to callback
_tqdm_monitor_stop = None
if progress_callback and not _is_torch_iterable:
import threading
from tqdm.auto import tqdm as _tqdm_cls
_tqdm_monitor_stop = threading.Event()
_total = len(dataset) if hasattr(dataset, "__len__") else 0
_desc = f"Applying chat template to {final_format}"
def _poll_tqdm():
while not _tqdm_monitor_stop.is_set():
for bar in list(getattr(_tqdm_cls, "_instances", set())):
try:
n = bar.n or 0
total = bar.total or _total
if total > 0 and n > 0:
pct = min(int(n * 100 / total), 100)
progress_callback(
status_message = f"{_desc}... {pct}% ({n:,}/{total:,})"
)
except (AttributeError, ReferenceError):
pass
_tqdm_monitor_stop.wait(3)
threading.Thread(target = _poll_tqdm, daemon = True).start()
formatted_dataset = dataset.map(_format_chatml, **dataset_map_kwargs)
if _tqdm_monitor_stop is not None:
_tqdm_monitor_stop.set()
return {
"dataset": formatted_dataset,
"success": True,
"warnings": warnings,
"errors": errors
}
except Exception as e:
errors.append(f"Failed to format ChatML dataset: {e}")
return {
"dataset": dataset,
"success": False,
"warnings": warnings,
"errors": errors
}
# UNKNOWN FORMAT
else:
errors.append(
f"Cannot apply chat template to format: {final_format}. "
f"This should not happen after custom mapping."
)
return {
"dataset": dataset,
"success": False,
"warnings": warnings,
"errors": errors
}