From bbb4b04caa37b4608db32163899fdda148a041e5 Mon Sep 17 00:00:00 2001
From: comfyanonymous <121283862+comfyanonymous@users.noreply.github.com>
Date: Tue, 11 Aug 2026 12:54:44 -0700
Subject: [PATCH] Don't depend on transformers for mistral and llama
 tokenizers. (#15503)

---
 comfy/text_encoders/bpe_tokenizer.py | 333 +++++++++++++++++++++++++++
 comfy/text_encoders/flux.py          |  43 +---
 comfy/text_encoders/hunyuan_video.py |   2 +-
 3 files changed, 339 insertions(+), 39 deletions(-)
 create mode 100644 comfy/text_encoders/bpe_tokenizer.py

diff --git a/comfy/text_encoders/bpe_tokenizer.py b/comfy/text_encoders/bpe_tokenizer.py
new file mode 100644
index 000000000..e49e36ca0
--- /dev/null
+++ b/comfy/text_encoders/bpe_tokenizer.py
@@ -0,0 +1,333 @@
+"""
+Pure-Python byte-level BPE tokenizer.
+Supports loading from HuggingFace tokenizer.json (LLaMA-style)
+and from Mistral tekken JSON blobs.
+No dependency on the `transformers`, `tokenizers`, or `regex` packages.
+"""
+import base64
+import json
+import os
+import re
+import unicodedata
+
+
+# This is also the default pattern used by the previous MistralConverter path.
+_LLAMA_PATTERN = r"""(?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\r\n\p{L}\p{N}]?\p{L}+|\p{N}{1,3}| ?[^\s\p{L}\p{N}]+[\r\n]*|\s*[\r\n]+|\s+(?!\S)|\s+"""
+_CONTRACTIONS = ("'re", "'ve", "'ll", "'s", "'t", "'m", "'d")
+
+
+def _is_letter(c):
+    return unicodedata.category(c)[0] == "L"
+
+
+def _is_number(c):
+    return unicodedata.category(c)[0] == "N"
+
+
+def _is_whitespace(c):
+    return c in " \t\n\r\v\f\x85\u2028\u2029" or unicodedata.category(c) == "Zs"
+
+
+def _split_llama(text):
+    pieces = []
+    i = 0
+    while i < len(text):
+        contraction = None
+        if text[i] == "'":
+            for suffix in _CONTRACTIONS:
+                if text[i:i + len(suffix)].casefold() == suffix:
+                    contraction = text[i:i + len(suffix)]
+                    break
+        if contraction is not None:
+            pieces.append(contraction)
+            i += len(contraction)
+            continue
+
+        j = i
+        if text[j] not in "\r\n" and not _is_letter(text[j]) and not _is_number(text[j]):
+            j += 1
+        if j < len(text) and _is_letter(text[j]):
+            j += 1
+            while j < len(text) and _is_letter(text[j]):
+                j += 1
+            pieces.append(text[i:j])
+            i = j
+            continue
+
+        if _is_number(text[i]):
+            j = i + 1
+            while j < len(text) and j - i < 3 and _is_number(text[j]):
+                j += 1
+            pieces.append(text[i:j])
+            i = j
+            continue
+
+        j = i
+        if text[j] == " ":
+            j += 1
+        punct_start = j
+        while j < len(text) and not _is_whitespace(text[j]) and not _is_letter(text[j]) and not _is_number(text[j]):
+            j += 1
+        if j > punct_start:
+            while j < len(text) and text[j] in "\r\n":
+                j += 1
+            pieces.append(text[i:j])
+            i = j
+            continue
+
+        if _is_whitespace(text[i]):
+            j = i + 1
+            while j < len(text) and _is_whitespace(text[j]):
+                j += 1
+            last_newline = max(text.rfind("\r", i, j), text.rfind("\n", i, j))
+            if last_newline >= i:
+                j = last_newline + 1
+            elif j < len(text) and j - i > 1:
+                j -= 1
+            pieces.append(text[i:j])
+            i = j
+            continue
+
+        pieces.append(text[i])
+        i += 1
+    return pieces
+
+
+def _make_split_pattern(pattern_str):
+    if pattern_str != _LLAMA_PATTERN:
+        raise ValueError(f"Unsupported tokenizer split pattern: {pattern_str}")
+    return _split_llama
+
+
+def _bytes_to_unicode():
+    bs = (list(range(ord("!"), ord("~") + 1))
+          + list(range(ord("¡"), ord("¬") + 1))
+          + list(range(ord("®"), ord("ÿ") + 1)))
+    cs = bs[:]
+    n = 0
+    for b in range(2**8):
+        if b not in bs:
+            bs.append(b)
+            cs.append(2**8 + n)
+            n += 1
+    cs = [chr(n) for n in cs]
+    return dict(zip(bs, cs))
+
+
+class BPETokenizer:
+    """Byte-level BPE tokenizer with optional BOS prepending."""
+
+    def __init__(self, vocab, merges_by_pair, special_token_ids, pattern_str,
+                 byte_encoder, byte_decoder, bos_id=None):
+        self._vocab = vocab                          # str -> int
+        self._inv_vocab = {v: k for k, v in vocab.items()}
+        self._merges = merges_by_pair                # (str, str) -> priority int
+        self._special_token_ids = special_token_ids  # str -> int
+        self._special_ids = set(special_token_ids.values())
+        self._byte_encoder = byte_encoder
+        self._byte_decoder = byte_decoder
+        self._bos_id = bos_id
+
+        self._split = _make_split_pattern(pattern_str)
+        sorted_specials = sorted(special_token_ids.keys(), key=len, reverse=True)
+        if sorted_specials:
+            self._special_split = re.compile(
+                '(' + '|'.join(re.escape(s) for s in sorted_specials) + ')'
+            )
+        else:
+            self._special_split = None
+
+    def _bpe_encode_piece(self, chars):
+        if len(chars) <= 1:
+            return chars
+        while True:
+            min_rank = float('inf')
+            best_pair = None
+            for i in range(len(chars) - 1):
+                r = self._merges.get((chars[i], chars[i + 1]), float('inf'))
+                if r < min_rank:
+                    min_rank = r
+                    best_pair = (chars[i], chars[i + 1])
+            if best_pair is None:
+                break
+            merged = best_pair[0] + best_pair[1]
+            new_chars = []
+            i = 0
+            while i < len(chars):
+                if i < len(chars) - 1 and chars[i] == best_pair[0] and chars[i + 1] == best_pair[1]:
+                    new_chars.append(merged)
+                    i += 2
+                else:
+                    new_chars.append(chars[i])
+                    i += 1
+            chars = new_chars
+            if len(chars) == 1:
+                break
+        return chars
+
+    def _encode_raw(self, text):
+        ids = []
+        parts = self._special_split.split(text) if self._special_split else [text]
+        for part in parts:
+            if not part:
+                continue
+            if part in self._special_token_ids:
+                ids.append(self._special_token_ids[part])
+            else:
+                for piece in self._split(part):
+                    byte_chars = [self._byte_encoder[b] for b in piece.encode('utf-8')]
+                    for tok in self._bpe_encode_piece(byte_chars):
+                        ids.append(self._vocab[tok])
+        return ids
+
+    def __call__(self, text):
+        ids = self._encode_raw(text)
+        if self._bos_id is not None:
+            ids = [self._bos_id] + ids
+        return {"input_ids": ids}
+
+    def get_vocab(self):
+        return dict(self._vocab)
+
+    def decode(self, token_ids, skip_special_tokens=True):
+        buf = bytearray()
+        for tid in token_ids:
+            s = self._inv_vocab.get(tid, '')
+            if tid in self._special_ids:
+                if not skip_special_tokens:
+                    buf.extend(s.encode('utf-8'))
+            else:
+                for c in s:
+                    buf.append(self._byte_decoder[c])
+        return buf.decode('utf-8', errors='replace')
+
+
+def _extract_pattern(pretok):
+    if pretok.get('type') == 'Sequence':
+        for sub in pretok.get('pretokenizers', []):
+            if sub.get('type') == 'Split':
+                pat = sub.get('pattern', {})
+                if 'Regex' in pat:
+                    return pat['Regex']
+    elif pretok.get('type') == 'Split':
+        pat = pretok.get('pattern', {})
+        if 'Regex' in pat:
+            return pat['Regex']
+    return None
+
+
+def _extract_bos_id(post_processor, special_token_ids):
+    if post_processor.get('type') == 'TemplateProcessing':
+        single = post_processor.get('single', [])
+        if single and 'SpecialToken' in single[0]:
+            bos_str = single[0]['SpecialToken']['id']
+            return special_token_ids.get(bos_str)
+    return None
+
+
+def from_tokenizer_json(path):
+    """Load a BPETokenizer from a directory containing tokenizer.json."""
+    tok_file = os.path.join(path, 'tokenizer.json')
+    with open(tok_file, encoding='utf-8') as f:
+        data = json.load(f)
+
+    vocab = dict(data['model']['vocab'])  # str -> int
+
+    merges_by_pair = {}
+    for i, merge_str in enumerate(data['model'].get('merges', [])):
+        a, b = merge_str.split(' ', 1)
+        if (a, b) not in merges_by_pair:
+            merges_by_pair[(a, b)] = i
+
+    special_token_ids = {}
+    for tok in data.get('added_tokens', []):
+        special_token_ids[tok['content']] = tok['id']
+        vocab[tok['content']] = tok['id']  # include in vocab for inv_vocab decode
+
+    pattern = _extract_pattern(data.get('pre_tokenizer', {}))
+    if pattern is None:
+        raise ValueError(f"Could not extract regex pattern from {tok_file}")
+
+    bos_id = _extract_bos_id(data.get('post_processor', {}), special_token_ids)
+
+    byte_encoder = _bytes_to_unicode()
+    byte_decoder = {v: k for k, v in byte_encoder.items()}
+
+    return BPETokenizer(vocab, merges_by_pair, special_token_ids, pattern,
+                        byte_encoder, byte_decoder, bos_id=bos_id)
+
+
+def from_tekken_json(data):
+    """Build a BPETokenizer from a Mistral tekken JSON blob (bytes or str)."""
+    mistral_vocab = json.loads(data)
+    config = mistral_vocab["config"]
+
+    byte_encoder = _bytes_to_unicode()
+    byte_decoder = {v: k for k, v in byte_encoder.items()}
+
+    def tbts(b):
+        return "".join(byte_encoder[ord(c)] for c in b.decode("latin-1"))
+
+    special_token_offset = config["default_num_special_tokens"]
+    max_vocab = config["default_vocab_size"] - special_token_offset
+
+    raw_vocab = {}
+    for w in mistral_vocab["vocab"]:
+        r = w["rank"]
+        if r >= max_vocab:
+            continue
+        raw_vocab[base64.b64decode(w["token_bytes"])] = r + special_token_offset
+
+    special_tokens_dict = {}
+    for w in mistral_vocab["special_tokens"]:
+        if "token_bytes" in w:
+            special_tokens_dict[base64.b64decode(w["token_bytes"])] = w["rank"]
+        else:
+            special_tokens_dict[w["token_str"]] = w["rank"]
+
+    all_special = list(special_tokens_dict.keys())
+    combined = dict(special_tokens_dict)
+    combined.update(raw_vocab)
+
+    bpe_vocab = {}
+    merge_triples = []
+    for token, rank in combined.items():
+        if token not in all_special:
+            bpe_vocab[tbts(token)] = rank
+            if len(token) == 1:
+                continue
+            local = []
+            for i in range(1, len(token)):
+                pl, pr = token[:i], token[i:]
+                if pl in combined and pr in combined and (pl + pr) in combined:
+                    local.append((pl, pr, rank))
+            local.sort(key=lambda x: (combined[x[0]], combined[x[1]]))
+            merge_triples.extend(local)
+        else:
+            tok_str = token.decode("utf-8", errors="replace") if isinstance(token, bytes) else token
+            bpe_vocab[tok_str] = rank
+
+    merge_triples.sort(key=lambda v: v[2])
+
+    merges_by_pair = {}
+    for i, (pl, pr, _) in enumerate(merge_triples):
+        pair = (tbts(pl), tbts(pr))
+        if pair not in merges_by_pair:
+            merges_by_pair[pair] = i
+
+    special_str_ids = {}
+    for tok in all_special:
+        tok_str = tok.decode("utf-8", errors="replace") if isinstance(tok, bytes) else tok
+        if tok_str in bpe_vocab:
+            special_str_ids[tok_str] = bpe_vocab[tok_str]
+
+    return BPETokenizer(bpe_vocab, merges_by_pair, special_str_ids, _LLAMA_PATTERN,
+                        byte_encoder, byte_decoder, bos_id=None)
+
+
+class LlamaTokenizerFast:
+    """Drop-in replacement for transformers.LlamaTokenizerFast (read-only use)."""
+
+    @staticmethod
+    def from_pretrained(path, **kwargs):
+        return from_tokenizer_json(path)
diff --git a/comfy/text_encoders/flux.py b/comfy/text_encoders/flux.py
index d5eb91dcb..fbdb1d13a 100644
--- a/comfy/text_encoders/flux.py
+++ b/comfy/text_encoders/flux.py
@@ -3,11 +3,10 @@ import comfy.text_encoders.t5
 import comfy.text_encoders.sd3_clip
 import comfy.text_encoders.llama
 import comfy.model_management
-from transformers import T5TokenizerFast, LlamaTokenizerFast, Qwen2Tokenizer
+from transformers import T5TokenizerFast, Qwen2Tokenizer
+from .bpe_tokenizer import from_tekken_json
 import torch
 import os
-import json
-import base64
 
 class T5XXLTokenizer(sd1_clip.SDTokenizer):
     def __init__(self, embedding_directory=None, tokenizer_data={}):
@@ -75,45 +74,13 @@ def flux_clip(dtype_t5=None, t5_quantization_metadata=None):
 def load_mistral_tokenizer(data):
     if torch.is_tensor(data):
         data = data.numpy().tobytes()
+    return {"tokenizer_object": from_tekken_json(data)}
 
-    try:
-        from transformers.integrations.mistral import MistralConverter
-    except ModuleNotFoundError:
-        from transformers.models.pixtral.convert_pixtral_weights_to_hf import MistralConverter
-
-    mistral_vocab = json.loads(data)
-
-    special_tokens = {}
-    vocab = {}
-
-    max_vocab = mistral_vocab["config"]["default_vocab_size"]
-    max_vocab -= len(mistral_vocab["special_tokens"])
-
-    for w in mistral_vocab["vocab"]:
-        r = w["rank"]
-        if r >= max_vocab:
-            continue
-
-        vocab[base64.b64decode(w["token_bytes"])] = r
-
-    for w in mistral_vocab["special_tokens"]:
-        if "token_bytes" in w:
-            special_tokens[base64.b64decode(w["token_bytes"])] = w["rank"]
-        else:
-            special_tokens[w["token_str"]] = w["rank"]
-
-    all_special = []
-    for v in special_tokens:
-        all_special.append(v)
-
-    special_tokens.update(vocab)
-    vocab = special_tokens
-    return {"tokenizer_object": MistralConverter(vocab=vocab, additional_special_tokens=all_special).converted(), "legacy": False}
 
 class MistralTokenizerClass:
     @staticmethod
-    def from_pretrained(path, **kwargs):
-        return LlamaTokenizerFast(**kwargs)
+    def from_pretrained(path, tokenizer_object=None, **kwargs):
+        return tokenizer_object
 
 class Mistral3Tokenizer(sd1_clip.SDTokenizer):
     def __init__(self, embedding_directory=None, embedding_size=5120, embedding_key='mistral3_24b', tokenizer_data={}):
diff --git a/comfy/text_encoders/hunyuan_video.py b/comfy/text_encoders/hunyuan_video.py
index 2ddb4da60..932a3d49b 100644
--- a/comfy/text_encoders/hunyuan_video.py
+++ b/comfy/text_encoders/hunyuan_video.py
@@ -2,7 +2,7 @@ from comfy import sd1_clip
 import comfy.model_management
 import comfy.text_encoders.llama
 from .hunyuan_image import HunyuanImageTokenizer
-from transformers import LlamaTokenizerFast
+from .bpe_tokenizer import LlamaTokenizerFast
 import torch
 import os
 import numbers