use prefix to replace force system

src/llamafactory/data/template.py

@@ -38,12 +38,12 @@ class Template:
     format_observation: "Formatter"
     format_tools: "Formatter"
     format_separator: "Formatter"
+    format_prefix: "Formatter"
     default_system: str
     stop_words: List[str]
     image_token: str
     efficient_eos: bool
     replace_eos: bool
-    force_system: bool
 
     def encode_oneturn(
         self,
@@ -102,8 +102,9 @@ class Template:
         system = system or self.default_system
         encoded_messages = []
         for i, message in enumerate(messages):
-            elements = []
+            elements = self.format_prefix.apply()
-            if i == 0 and (system or tools or self.force_system):
+
+            if i == 0 and (system or tools):
                 tool_text = self.format_tools.apply(content=tools)[0] if tools else ""
                 elements += self.format_system.apply(content=(system + tool_text))
 
@@ -193,9 +194,10 @@ class Llama2Template(Template):
         system = system or self.default_system
         encoded_messages = []
         for i, message in enumerate(messages):
-            elements = []
+            elements = self.format_prefix.apply()
+
             system_text = ""
-            if i == 0 and (system or tools or self.force_system):
+            if i == 0 and (system or tools):
                 tool_text = self.format_tools.apply(content=tools)[0] if tools else ""
                 system_text = self.format_system.apply(content=(system + tool_text))[0]
 
@@ -230,12 +232,12 @@ def _register_template(
     format_observation: Optional["Formatter"] = None,
     format_tools: Optional["Formatter"] = None,
     format_separator: Optional["Formatter"] = None,
+    format_prefix: Optional["Formatter"] = None,
     default_system: str = "",
     stop_words: List[str] = [],
     image_token: str = "<image>",
     efficient_eos: bool = False,
     replace_eos: bool = False,
-    force_system: bool = False,
 ) -> None:
     r"""
     Registers a chat template.
@@ -272,6 +274,7 @@ def _register_template(
     )
     default_tool_formatter = ToolFormatter(tool_format="default")
     default_separator_formatter = EmptyFormatter()
+    default_prefix_formatter = EmptyFormatter()
     TEMPLATES[name] = template_class(
         format_user=format_user or default_user_formatter,
         format_assistant=format_assistant or default_assistant_formatter,
@@ -280,12 +283,12 @@ def _register_template(
         format_observation=format_observation or format_user or default_user_formatter,
         format_tools=format_tools or default_tool_formatter,
         format_separator=format_separator or default_separator_formatter,
+        format_prefix=format_prefix or default_prefix_formatter,
         default_system=default_system,
         stop_words=stop_words,
         image_token=image_token,
         efficient_eos=efficient_eos,
         replace_eos=replace_eos,
-        force_system=force_system,
     )
 
 
@@ -329,7 +332,7 @@ def _convert_slots_to_jinja(slots: "SLOTS", tokenizer: "PreTrainedTokenizer", pl
 
 
 def _get_jinja_template(template: "Template", tokenizer: "PreTrainedTokenizer") -> str:
-    jinja_template = ""
+    jinja_template = _convert_slots_to_jinja(template.format_prefix.apply(), tokenizer)
 
     if template.default_system:
         jinja_template += "{% set system_message = '" + _jinja_escape(template.default_system) + "' %}"
@@ -339,11 +342,7 @@ def _get_jinja_template(template: "Template", tokenizer: "PreTrainedTokenizer")
     )
 
     system_message = _convert_slots_to_jinja(template.format_system.apply(), tokenizer, placeholder="system_message")
-    if isinstance(template, Llama2Template):
+    if not isinstance(template, Llama2Template):
-        pass
-    elif template.force_system:
-        jinja_template += "{{ " + system_message + " }}"
-    else:
         jinja_template += "{% if system_message is defined %}{{ " + system_message + " }}{% endif %}"
 
     jinja_template += "{% for message in messages %}"
@@ -459,9 +458,8 @@ _register_template(
 _register_template(
     name="belle",
     format_user=StringFormatter(slots=["Human: {{content}}\n\nBelle: "]),
-    format_system=StringFormatter(slots=[{"bos_token"}, "{{content}}"]),
     format_separator=EmptyFormatter(slots=["\n\n"]),
-    force_system=True,
+    format_prefix=EmptyFormatter(slots=[{"bos_token"}]),
 )
 
 
@@ -486,10 +484,9 @@ _register_template(
 _register_template(
     name="chatglm2",
     format_user=StringFormatter(slots=["[Round {{idx}}]\n\n问：{{content}}\n\n答："]),
-    format_system=StringFormatter(slots=[{"token": "[gMASK]"}, {"token": "sop"}, "{{content}}"]),
     format_separator=EmptyFormatter(slots=["\n\n"]),
+    format_prefix=EmptyFormatter(slots=[{"token": "[gMASK]"}, {"token": "sop"}]),
     efficient_eos=True,
-    force_system=True,
 )
 
 
@@ -497,14 +494,14 @@ _register_template(
     name="chatglm3",
     format_user=StringFormatter(slots=[{"token": "<|user|>"}, "\n", "{{content}}", {"token": "<|assistant|>"}]),
     format_assistant=StringFormatter(slots=["\n", "{{content}}"]),
-    format_system=StringFormatter(slots=[{"token": "[gMASK]"}, {"token": "sop"}, "{{content}}"]),
+    format_system=StringFormatter(slots=[{"token": "<|system|>"}, "\n", "{{content}}"]),
     format_function=FunctionFormatter(slots=["{{name}}\n{{arguments}}"]),
     format_observation=StringFormatter(
         slots=[{"token": "<|observation|>"}, "\n", "{{content}}", {"token": "<|assistant|>"}]
     ),
+    format_prefix=EmptyFormatter(slots=[{"token": "[gMASK]"}, {"token": "sop"}]),
     stop_words=["<|user|>", "<|observation|>"],
     efficient_eos=True,
-    force_system=True,
 )
 
 
@@ -512,13 +509,12 @@ _register_template(
     name="chatglm3_system",
     format_user=StringFormatter(slots=[{"token": "<|user|>"}, "\n", "{{content}}", {"token": "<|assistant|>"}]),
     format_assistant=StringFormatter(slots=["\n", "{{content}}"]),
-    format_system=StringFormatter(
+    format_system=StringFormatter(slots=[{"token": "<|system|>"}, "\n", "{{content}}"]),
-        slots=[{"token": "[gMASK]"}, {"token": "sop"}, {"token": "<|system|>"}, "\n", "{{content}}"]
-    ),
     format_function=FunctionFormatter(slots=["{{name}}\n{{arguments}}"]),
     format_observation=StringFormatter(
         slots=[{"token": "<|observation|>"}, "\n", "{{content}}", {"token": "<|assistant|>"}]
     ),
+    format_prefix=EmptyFormatter(slots=[{"token": "[gMASK]"}, {"token": "sop"}]),
     default_system=(
         "You are ChatGLM3, a large language model trained by Zhipu.AI. "
         "Follow the user's instructions carefully. Respond using markdown."
@@ -553,8 +549,7 @@ _register_template(
 
 _register_template(
     name="codegeex2",
-    format_system=StringFormatter(slots=[{"token": "[gMASK]"}, {"token": "sop"}, "{{content}}"]),
+    format_prefix=EmptyFormatter(slots=[{"token": "[gMASK]"}, {"token": "sop"}]),
-    force_system=True,
 )
 
 
@@ -581,8 +576,7 @@ _register_template(
 _register_template(
     name="cpm",
     format_user=StringFormatter(slots=["<用户>{{content}}<AI>"]),
-    format_system=StringFormatter(slots=[{"bos_token"}, "{{content}}"]),
+    format_prefix=EmptyFormatter(slots=[{"bos_token"}]),
-    force_system=True,
 )
 
 
@@ -615,8 +609,7 @@ _register_template(
 _register_template(
     name="deepseek",
     format_user=StringFormatter(slots=["User: {{content}}\n\nAssistant:"]),
-    format_system=StringFormatter(slots=[{"bos_token"}, "{{content}}"]),
+    format_prefix=EmptyFormatter(slots=[{"bos_token"}]),
-    force_system=True,
 )
 
 
@@ -648,9 +641,8 @@ _register_template(
     name="empty",
     format_user=StringFormatter(slots=["{{content}}"]),
     format_assistant=StringFormatter(slots=["{{content}}"]),
-    format_system=StringFormatter(slots=[{"bos_token"}, "{{content}}"]),
+    format_prefix=EmptyFormatter(slots=[{"bos_token"}]),
     efficient_eos=True,
-    force_system=True,
 )
 
 
@@ -672,13 +664,12 @@ _register_template(
 _register_template(
     name="gemma",
     format_user=StringFormatter(slots=["<start_of_turn>user\n{{content}}<end_of_turn>\n<start_of_turn>model\n"]),
-    format_system=StringFormatter(slots=[{"bos_token"}, "{{content}}"]),
     format_observation=StringFormatter(
         slots=["<start_of_turn>tool\n{{content}}<end_of_turn>\n<start_of_turn>model\n"]
     ),
     format_separator=EmptyFormatter(slots=["<end_of_turn>\n"]),
+    format_prefix=EmptyFormatter(slots=[{"bos_token"}]),
     efficient_eos=True,
-    force_system=True,
 )
 
 
@@ -686,13 +677,13 @@ _register_template(
     name="glm4",
     format_user=StringFormatter(slots=["<|user|>\n{{content}}<|assistant|>"]),
     format_assistant=StringFormatter(slots=["\n{{content}}"]),
-    format_system=StringFormatter(slots=["[gMASK]<sop><|system|>\n{{content}}"]),
+    format_system=StringFormatter(slots=["<|system|>\n{{content}}"]),
     format_function=FunctionFormatter(slots=["{{name}}\n{{arguments}}"]),
     format_observation=StringFormatter(slots=["<|observation|>\n{{content}}<|assistant|>"]),
     format_tools=ToolFormatter(tool_format="glm4"),
+    format_prefix=EmptyFormatter(slots=["[gMASK]<sop>"]),
     stop_words=["<|user|>", "<|observation|>"],
     efficient_eos=True,
-    force_system=True,
 )
 
 
@@ -768,24 +759,21 @@ _register_template(
 _register_template(
     name="mistral",
     format_user=StringFormatter(slots=["[INST] {{content}} [/INST]"]),
-    format_system=StringFormatter(slots=[{"bos_token"}, "{{content}}"]),
+    format_prefix=EmptyFormatter(slots=[{"bos_token"}]),
-    force_system=True,
 )
 
 
 _register_template(
     name="olmo",
     format_user=StringFormatter(slots=["<|user|>\n{{content}}<|assistant|>\n"]),
-    format_system=StringFormatter(slots=[{"eos_token"}, "{{content}}"]),
+    format_prefix=EmptyFormatter(slots=[{"eos_token"}]),
-    force_system=True,
 )
 
 
 _register_template(
     name="openchat",
     format_user=StringFormatter(slots=["GPT4 Correct User: {{content}}", {"eos_token"}, "GPT4 Correct Assistant:"]),
-    format_system=StringFormatter(slots=[{"bos_token"}, "{{content}}"]),
+    format_prefix=EmptyFormatter(slots=[{"bos_token"}]),
-    force_system=True,
 )
 
 
@@ -799,18 +787,16 @@ _register_template(
             )
         ]
     ),
-    format_system=StringFormatter(slots=[{"bos_token"}, "{{content}}"]),
+    format_prefix=EmptyFormatter(slots=[{"bos_token"}]),
     stop_words=["<|eot_id|>"],
     replace_eos=True,
-    force_system=True,
 )
 
 
 _register_template(
     name="orion",
     format_user=StringFormatter(slots=["Human: {{content}}\n\nAssistant: ", {"eos_token"}]),
-    format_system=StringFormatter(slots=[{"bos_token"}, "{{content}}"]),
+    format_prefix=EmptyFormatter(slots=[{"bos_token"}]),
-    force_system=True,
 )
 
 
@@ -852,7 +838,6 @@ _register_template(
     format_separator=EmptyFormatter(slots=["\n"]),
     stop_words=["<|end|>"],
     replace_eos=True,
-    force_system=True,
 )