Merge branch 'pytorch:main' into patch-30

Author: mikekgfb

install/requirements.txt

@@ -9,6 +9,10 @@ gguf
 # Tiktoken tokenizer for Llama 3 and other advanced models
 tiktoken
 
+# Tokenizers and jinja2 for other non-llama models that use HF tokenizers
+tokenizers
+jinja2
+
 # Miscellaneous
 snakeviz
 sentencepiece

tests/conftest.py

@@ -0,0 +1,12 @@
+"""
+Global pytest config, fixtures, and helpers go here!
+"""
+
+# Standard
+import os
+import sys
+
+# Make sure tests can import torchchat
+sys.path.append(
+    os.path.realpath(os.path.join(os.path.dirname(__file__), ".."))
+)

tests/test_chat_formatters.py

@@ -0,0 +1,216 @@
+"""
+Unit tests for chat formatters
+"""
+
+# Third Party
+import pytest
+
+# Local
+from torchchat.generate import (
+    HFTokenizerChatFormatter,
+    Llama2ChatFormatter,
+    Llama3ChatFormatter,
+)
+
+## Helpers #####################################################################
+
+class DummyTokenizer:
+    """Dummy tokenizer that encodes as strings so it's easy to check formatting"""
+    def encode(self, text, *_, **__):
+        return text
+
+
+class DummySPTokenizer(DummyTokenizer):
+    """Emulated Sentencepiece tokenizer with bos/eos"""
+    bos = "<s>"
+    eos = "</s>"
+
+
+class DummyLlama3Tokenizer(DummyTokenizer):
+    class _IdentityDict:
+        def __getitem__(self, key):
+            return key
+    special_tokens = _IdentityDict()
+
+
+class DummyHFTokenizer(DummyTokenizer):
+    """Dummy made up chat template scheme"""
+    # Sequence
+    bos = "<bos>"
+    # Turn
+    bot = "<bot>"
+    eot = "<eot>"
+    # Role
+    bor = "<bor>"
+    eor = "<eor>"
+    def apply_chat_template(self, messages, add_generation_prompt):
+        out = [self.bos]
+        role = None
+        for msg in messages:
+            role = msg["role"]
+            content = msg["content"]
+            out.append(f"{self.bot}{self.bor}{role}{self.eor}{content}{self.eot}")
+        if add_generation_prompt and role != "assistant":
+            out.append(f"{self.bot}{self.bor}assistant{self.eor}")
+        return "\n".join(out)
+
+
+def check_rendering(fmt, messages, expected, add_generation_prompt):
+    """Render messages and compare to expected output"""
+    assert "".join(fmt.encode_dialog_prompt(messages, add_generation_prompt)) == expected
+
+
+def make_message(role, text):
+    return {"role": role, "content": text}
+
+
+SYSTEM_PROMPT = "You are a helpful assistant, feel free to ask me anything."
+USER1 = "Hello world!"
+ASSISTANT1 = "Greetings! How can I help you?"
+USER2 = "Why is the sky blue?"
+ASSISTANT2 = "The sky appears blue because of a phenomenon called Rayleigh scattering."
+
+
+# Stock sets of messages to test
+MSGS_NO_SYS= [
+    make_message("user", USER1),
+]
+MSGS_SYS_USR = [
+    make_message("system", SYSTEM_PROMPT),
+    make_message("user", USER1),
+]
+MSGS_SYS_USR_ASST = [
+    make_message("system", SYSTEM_PROMPT),
+    make_message("user", USER1),
+    make_message("assistant", ASSISTANT1),
+]
+MSGS_MULTI_TURN = [
+    make_message("system", SYSTEM_PROMPT),
+    make_message("user", USER1),
+    make_message("assistant", ASSISTANT1),
+    make_message("user", USER2),
+    make_message("assistant", ASSISTANT2),
+]
+
+## Llama2ChatFormatter #########################################################
+
+@pytest.mark.parametrize(
+    ["messages", "expected"],
+    [
+        # single user message (no system prompt)
+        (MSGS_NO_SYS, f"<s>[INST] {USER1} [/INST]"),
+        # sys, usr
+        (MSGS_SYS_USR, f"""<s>[INST] <<SYS>>
+{SYSTEM_PROMPT}
+<</SYS>>
+
+{USER1} [/INST]"""),
+        # sys, usr, asst
+        (MSGS_SYS_USR_ASST, f"""<s>[INST] <<SYS>>
+{SYSTEM_PROMPT}
+<</SYS>>
+
+{USER1} [/INST] {ASSISTANT1} </s>
+"""),
+        # sys, usr, asst, usr, asst
+        (MSGS_MULTI_TURN, f"""<s>[INST] <<SYS>>
+{SYSTEM_PROMPT}
+<</SYS>>
+
+{USER1} [/INST] {ASSISTANT1} </s>
+<s>[INST] {USER2} [/INST] {ASSISTANT2} </s>
+"""),
+    ]
+)
+def test_llama2_chat_formatter(messages, expected):
+    """Tests for Llama2 following the official guide
+    https://www.llama.com/docs/model-cards-and-prompt-formats/meta-llama-2/
+    """
+    tok = DummySPTokenizer()
+    fmt = Llama2ChatFormatter(tok)
+    # NOTE: add_generation_prompt not used by Llama2
+    check_rendering(fmt, messages, expected, True)
+
+## Llama3ChatFormatter #########################################################
+
+@pytest.mark.parametrize(
+    ["messages", "expected"],
+    [
+        # single user message (no system prompt)
+        (MSGS_NO_SYS, f"""<|begin_of_text|><|start_header_id|>user<|end_header_id|>
+
+{USER1}<|eot_id|>"""),
+        # sys, usr
+        (MSGS_SYS_USR, f"""<|begin_of_text|><|start_header_id|>system<|end_header_id|>
+
+{SYSTEM_PROMPT}<|eot_id|><|start_header_id|>user<|end_header_id|>
+
+{USER1}<|eot_id|>"""),
+        # sys, usr, asst
+        (MSGS_SYS_USR_ASST, f"""<|begin_of_text|><|start_header_id|>system<|end_header_id|>
+
+{SYSTEM_PROMPT}<|eot_id|><|start_header_id|>user<|end_header_id|>
+
+{USER1}<|eot_id|><|start_header_id|>assistant<|end_header_id|>
+
+{ASSISTANT1}<|eot_id|>"""),
+        # sys, usr, asst, usr, asst
+        (MSGS_MULTI_TURN, f"""<|begin_of_text|><|start_header_id|>system<|end_header_id|>
+
+{SYSTEM_PROMPT}<|eot_id|><|start_header_id|>user<|end_header_id|>
+
+{USER1}<|eot_id|><|start_header_id|>assistant<|end_header_id|>
+
+{ASSISTANT1}<|eot_id|><|start_header_id|>user<|end_header_id|>
+
+{USER2}<|eot_id|><|start_header_id|>assistant<|end_header_id|>
+
+{ASSISTANT2}<|eot_id|>"""),
+    ]
+)
+@pytest.mark.parametrize("add_generation_prompt", [True, False])
+def test_llama3_chat_formatter(messages, expected, add_generation_prompt):
+    """Tests for Llama3 following the official guide
+    https://www.llama.com/docs/model-cards-and-prompt-formats/meta-llama-3/
+    """
+    tok = DummyLlama3Tokenizer()
+    fmt = Llama3ChatFormatter(tok)
+    # No assistant prompt added if the last message is from the assistant
+    if add_generation_prompt and messages[-1]["role"] != "assistant":
+        expected += "<|start_header_id|>assistant<|end_header_id|>\n\n"
+    check_rendering(fmt, messages, expected, add_generation_prompt)
+
+## HFTokenizerChatFormatter ####################################################
+
+@pytest.mark.parametrize(
+    ["messages", "expected"],
+    [
+        # single user message (no system prompt)
+        (MSGS_NO_SYS, f"""<bos>
+<bot><bor>user<eor>{USER1}<eot>"""),
+        # sys, usr
+        (MSGS_SYS_USR, f"""<bos>
+<bot><bor>system<eor>{SYSTEM_PROMPT}<eot>
+<bot><bor>user<eor>{USER1}<eot>"""),
+        # sys, usr, asst
+        (MSGS_SYS_USR_ASST, f"""<bos>
+<bot><bor>system<eor>{SYSTEM_PROMPT}<eot>
+<bot><bor>user<eor>{USER1}<eot>
+<bot><bor>assistant<eor>{ASSISTANT1}<eot>"""),
+        # sys, usr, asst, usr, asst
+        (MSGS_MULTI_TURN, f"""<bos>
+<bot><bor>system<eor>{SYSTEM_PROMPT}<eot>
+<bot><bor>user<eor>{USER1}<eot>
+<bot><bor>assistant<eor>{ASSISTANT1}<eot>
+<bot><bor>user<eor>{USER2}<eot>
+<bot><bor>assistant<eor>{ASSISTANT2}<eot>"""),
+    ]
+)
+@pytest.mark.parametrize("add_generation_prompt", [True, False])
+def test_hf_chat_formatter(messages, expected, add_generation_prompt):
+    tok = DummyHFTokenizer()
+    fmt = HFTokenizerChatFormatter(tok)
+    # No assistant prompt added if the last message is from the assistant
+    if add_generation_prompt and messages[-1]["role"] != "assistant":
+        expected += f"\n{tok.bot}{tok.bor}assistant{tok.eor}"
+    check_rendering(fmt, messages, expected, add_generation_prompt)

tokenizer/hf_tokenizer.py

@@ -5,11 +5,12 @@
 # LICENSE file in the root directory of this source tree.
 
 # Standard
-from typing import List, Optional
+from typing import Dict, List, Optional
 import json
 import os
 
 # Third Party
+import jinja2
 from tokenizers import Tokenizer
 
 # Local
@@ -37,6 +38,9 @@ def __init__(self, file_path: str):
         # Load the tokenizer itself
         self._tokenizer = Tokenizer.from_file(tokenizer_path)
 
+        # Load the chat template if we have a config path
+        self._chat_template: Optional[jinja2.Template] = None
+
         # If available, parse bos/eos tokens from the tokenizer config
         self._bos_id, self._eos_id = None, None
         if tokenizer_config_path is not None:
@@ -48,6 +52,8 @@ def __init__(self, file_path: str):
                 self._bos_id = self._tokenizer.token_to_id(bos_token)
             if eos_token is not None:
                 self._eos_id = self._tokenizer.token_to_id(eos_token)
+            if chat_template_str := tok_config.get("chat_template"):
+                self._chat_template = jinja2.Template(chat_template_str)
 
         # If no eos/bos tokens found, go looking for them!
         if None in [self._bos_id, self._eos_id]:
@@ -70,6 +76,8 @@ def _look_for_special_token(added_tokens: dict, search_strs: List[str]) -> Optio
             if len(candidate_toks) == 1:
                 return candidate_toks[0]["id"]
 
+    ## Interface ##
+
     def encode(
         self,
         s: str,
@@ -90,3 +98,21 @@ def bos_id(self) -> int:
 
     def eos_id(self) -> int:
         return self._eos_id
+
+    ## Additional Public Methods ##
+
+    def has_chat_template(self) -> bool:
+        return bool(self._chat_template)
+
+    def apply_chat_template(
+        self,
+        dialog: List[Dict[str, str]],
+        add_generation_prompt: bool = False,
+    ) -> str:
+        """If configured with a chat template, apply it to the list of messages
+        """
+        if not self._chat_template:
+            raise ValueError("No chat template configured!")
+        return self._chat_template.render(
+            messages=dialog, add_generation_prompt=add_generation_prompt
+        )