Files
vllm/rust/src/parser/src/tool/json/internlm2.rs
T

349 lines
13 KiB
Rust

use super::{JsonToolCallConfig, JsonToolCallParser, JsonToolCallWhitespace};
use crate::tool::{Result, Tool, ToolParser, ToolParserOutput};
const INTERNLM2_CONFIG: JsonToolCallConfig = JsonToolCallConfig {
parser_name: "InternLM2",
start_marker: "<|action_start|><|plugin|>",
end_marker: "<|action_end|>",
marker_whitespace: JsonToolCallWhitespace::Optional,
delimiter: None,
name_key: "name",
// The Python parser's `get_arguments()` accepts either `parameters` or
// `arguments` and prefers `parameters` when both are present. This Rust
// parser uses first-encountered semantics because the header parser only
// permits one args key per tool-call object; if a future model emits
// both keys in the same object, the Rust port will accept the first one
// and reject the trailing one as a syntax error rather than silently
// shadowing it.
arguments_key: &["parameters", "arguments"],
};
/// Tool parser for InternLM2 special-token wrapped JSON tool calls.
///
/// Example tool call content:
///
/// ```text
/// <|action_start|><|plugin|>{"name": "get_weather", "parameters": {"location":"Tokyo"}}<|action_end|>
/// ```
///
/// Arguments are already OpenAI-style JSON text, so they are streamed as raw
/// argument deltas without schema conversion or JSON normalization.
///
/// # Divergences from the Python reference
///
/// This Rust port intentionally diverges from
/// `vllm/tool_parsers/internlm2_tool_parser.py` in two user-visible ways:
///
/// - **Parallel tool calls are supported.** Python silently drops every `<|action_start|>` block
/// after the first (`current_tool_id > 0` returns an empty delta); this parser emits every
/// well-formed block with incrementing `tool_index`. Models that legitimately emit multiple
/// action blocks therefore produce more tool calls under Rust than under Python.
/// - **End-marker bytes inside JSON string values are preserved.** Python does
/// `action.split("<|action_end|>")[0]` which truncates regardless of JSON context; this parser
/// scans matched braces and quotes so a literal `<|action_end|>` inside an arguments string is
/// forwarded intact.
/// - **Only whitespace is allowed before the `{`.** Python's non-streaming
/// `action[action.find("{"):]` drops any bytes before the first `{`, but its streaming path has
/// no equivalent and the model format always emits `<|plugin|>{...`; this parser allows only
/// whitespace there, matching the other JSON parsers in this crate.
/// - **Truncated tool calls error rather than silently dropping.** Python's streaming wrapper
/// swallows mid-stream errors with `except Exception: return None` (logging a traceback) while
/// its non-streaming path raises `JSONDecodeError`; this parser returns an `incomplete InternLM2
/// tool call` error from `finish()`, matching the other JSON parsers and Python's non-streaming
/// behavior.
///
/// # Known unaddressed divergences (TODO)
///
/// The following Python behaviors are NOT yet matched. They are deferred to
/// follow-up work because they require non-local changes to the shared
/// `JsonToolCallParser` core that would affect Hermes / Llama / Mistral /
/// Qwen as well. If a real-world InternLM2 deployment hits one of these,
/// prioritize the corresponding fix.
///
/// - **Arguments value type.** The shared core requires the arguments value to be a JSON object
/// (`take_json_object` rejects anything not starting with `{`). Python's
/// `json.dumps(action_dict.get("parameters", ...))` accepts `null`, arrays, strings, and numbers
/// and round-trips them verbatim. Models that legitimately emit `"parameters":null` will hard-
/// fail under Rust.
/// - **Unknown arguments key.** Python falls back to `{}` via `action_dict.get("parameters",
/// action_dict.get("arguments", {}))` when neither key is present; the Rust header parser raises
/// `parsing failed: invalid InternLM2` for any unrecognized key. A model that emits a typo (e.g.
/// `"params"`) breaks the whole response.
/// - **Field order independence.** The header parser requires the JSON keys to appear in the order
/// `name` then arguments key. Python's `json.loads` + `dict.get` is order-independent, so a model
/// emitting `{"parameters":{...},"name":"foo"}` parses in Python but fails in Rust.
pub struct Internlm2ToolParser {
inner: JsonToolCallParser,
}
impl Internlm2ToolParser {
/// Create an InternLM2 tool parser.
fn new(_tools: &[Tool]) -> Self {
Self {
inner: JsonToolCallParser::new(INTERNLM2_CONFIG),
}
}
}
impl ToolParser for Internlm2ToolParser {
/// Create a boxed InternLM2 tool parser.
fn create(tools: &[Tool]) -> Result<Box<dyn ToolParser>>
where
Self: Sized + 'static,
{
Ok(Box::new(Self::new(tools)))
}
/// Preserve special-token markers while decoding, since
/// `<|action_start|>`, `<|plugin|>`, and `<|action_end|>` are tokenizer
/// special tokens in InternLM2 models.
fn preserve_special_tokens(&self) -> bool {
true
}
/// Feed one decoded text chunk through the InternLM2 parser.
fn parse_into(&mut self, chunk: &str, output: &mut ToolParserOutput) -> Result<()> {
self.inner.parse_into(chunk, output)
}
/// Flush any buffered partial state at end of stream.
fn finish(&mut self) -> Result<ToolParserOutput> {
self.inner.finish()
}
/// Clear parser state and return currently uncommitted buffered text.
fn reset(&mut self) -> String {
self.inner.reset()
}
}
#[cfg(test)]
mod tests {
use expect_test::expect;
use thiserror_ext::AsReport;
use super::Internlm2ToolParser;
use crate::tool::test_utils::{collect_stream, split_by_chars, test_tools};
use crate::tool::{ToolParser, ToolParserOutput, ToolParserTestExt as _};
const ACTION_START: &str = "<|action_start|><|plugin|>";
const ACTION_END: &str = "<|action_end|>";
fn build_tool_call(function_name: &str, args_key: &str, arguments: &str) -> String {
format!(
r#"{ACTION_START}{{"name":"{function_name}","{args_key}":{arguments}}}{ACTION_END}"#
)
}
#[test]
fn internlm2_parse_complete_without_tool_call_keeps_text() {
let mut parser = Internlm2ToolParser::new(&test_tools());
let result = parser.parse_complete("Hello, world!").unwrap();
assert_eq!(result.normal_text(), "Hello, world!");
assert!(result.calls().is_empty());
}
#[test]
fn internlm2_parse_complete_extracts_parameters_key() {
let mut parser = Internlm2ToolParser::new(&test_tools());
let arguments = r#"{"location":"Tokyo","days":"3"}"#;
let result = parser
.parse_complete(&format!(
"Let me check.\n{}",
build_tool_call("get_weather", "parameters", arguments)
))
.unwrap();
assert_eq!(result.normal_text(), "Let me check.\n");
assert_eq!(result.calls().len(), 1);
assert_eq!(result.calls()[0].tool_index, 0);
assert_eq!(result.calls()[0].name.as_deref(), Some("get_weather"));
assert_eq!(result.calls()[0].arguments, arguments);
}
#[test]
fn internlm2_parse_complete_extracts_arguments_key_fallback() {
let mut parser = Internlm2ToolParser::new(&test_tools());
let arguments = r#"{"location":"Tokyo"}"#;
let result = parser
.parse_complete(&build_tool_call("get_weather", "arguments", arguments))
.unwrap();
assert_eq!(result.calls().len(), 1);
assert_eq!(result.calls()[0].name.as_deref(), Some("get_weather"));
assert_eq!(result.calls()[0].arguments, arguments);
}
#[test]
fn internlm2_accepts_whitespace_after_plugin_marker() {
let mut parser = Internlm2ToolParser::new(&test_tools());
let result = parser
.parse_complete(&format!(
r#"{ACTION_START}
{{"name":"get_weather","parameters":{{}}}}{ACTION_END}"#
))
.unwrap();
assert_eq!(result.calls().len(), 1);
assert_eq!(result.calls()[0].name.as_deref(), Some("get_weather"));
}
#[test]
fn internlm2_does_not_validate_or_normalize_arguments() {
let mut parser = Internlm2ToolParser::new(&test_tools());
let arguments = r#"{"location":"Tokyo",}"#;
let result = parser
.parse_complete(&build_tool_call("get_weather", "parameters", arguments))
.unwrap();
assert_eq!(result.calls()[0].arguments, arguments);
}
#[test]
fn internlm2_streaming_emits_argument_deltas() {
let mut parser = Internlm2ToolParser::new(&test_tools());
let chunks = [
"preface <|action",
"_start|><|plugin|>",
r#"{"name":"get_weather","parameters":"#,
r#"{"location":"#,
r#""Beijing""#,
r#"}"#,
r#"}<|action_end|> suffix"#,
];
let mut result = ToolParserOutput::default();
let mut observed_arguments = Vec::new();
for chunk in chunks {
let next = parser.parse_chunk(chunk).unwrap();
observed_arguments.extend(
next.calls()
.iter()
.filter(|call| call.name.is_none())
.map(|call| call.arguments.clone()),
);
result.append(next);
}
result.append(parser.finish().unwrap());
assert_eq!(
observed_arguments,
[r#"{"location":"#, r#""Beijing""#, r#"}"#]
);
assert_eq!(result.normal_text(), "preface suffix");
assert_eq!(
result.coalesce().calls()[0].arguments,
r#"{"location":"Beijing"}"#
);
}
#[test]
fn internlm2_streaming_handles_split_markers() {
let input = format!(
"hello {}",
build_tool_call("get_weather", "parameters", r#"{"location":"Tokyo"}"#)
);
let chunks = split_by_chars(&input, 5);
let mut parser = Internlm2ToolParser::new(&test_tools());
let result = collect_stream(&mut parser, &chunks);
assert_eq!(result.normal_text(), "hello ");
assert_eq!(result.calls().len(), 1);
assert_eq!(result.calls()[0].arguments, r#"{"location":"Tokyo"}"#);
}
#[test]
fn internlm2_streaming_extracts_multiple_blocks() {
let input = format!(
"{}{}",
build_tool_call("get_weather", "parameters", r#"{"location":"Shanghai"}"#),
build_tool_call("add", "arguments", r#"{"x":1,"y":2}"#),
);
let chunks = split_by_chars(&input, 7);
let mut parser = Internlm2ToolParser::new(&test_tools());
let result = collect_stream(&mut parser, &chunks);
expect![[r#"
ToolParserOutput {
events: [
ToolCall(
ToolCallDelta {
tool_index: 0,
name: Some(
"get_weather",
),
arguments: "{\"location\":\"Shanghai\"}",
},
),
ToolCall(
ToolCallDelta {
tool_index: 1,
name: Some(
"add",
),
arguments: "{\"x\":1,\"y\":2}",
},
),
],
}
"#]]
.assert_debug_eq(&result);
}
#[test]
fn internlm2_keeps_end_marker_literal_inside_json_string() {
let mut parser = Internlm2ToolParser::new(&test_tools());
let arguments = format!(r#"{{"text":"literal {ACTION_END} inside"}}"#);
let input = build_tool_call("echo", "parameters", &arguments);
let result = parser.parse_complete(&input).unwrap();
assert_eq!(result.calls().len(), 1);
assert_eq!(result.calls()[0].arguments, arguments);
}
#[test]
fn internlm2_finish_errors_on_truncated_tool_call() {
let mut parser = Internlm2ToolParser::new(&test_tools());
let pre_finish = parser
.parse_chunk(&format!(
r#"{ACTION_START}{{"name":"get_weather","parameters":{{"location""#
))
.unwrap();
let error = parser.finish().unwrap_err();
assert_eq!(
pre_finish.calls()[0].name.as_deref(),
Some("get_weather"),
"name delta is still emitted from parse_chunk() before truncation",
);
assert!(
error.to_report_string().contains("incomplete InternLM2 tool call"),
"finish() reports the truncated tool call as incomplete: {}",
error.to_report_string(),
);
}
#[test]
fn internlm2_unknown_arguments_key_fails() {
let mut parser = Internlm2ToolParser::new(&test_tools());
let input = build_tool_call("get_weather", "params", r#"{"location":"Tokyo"}"#);
let error = parser.parse_chunk(&input).unwrap_err();
expect![[r#"
tool parser parsing failed: near "{\"name\":\"get_weather\",\"params\":{\"location\":\"Tokyo\"}}<|action_end|>": invalid InternLM2
expected `parameters`, `arguments`"#]]
.assert_eq(&error.to_report_string());
}
#[test]
fn internlm2_preserve_special_tokens_is_true() {
let parser = Internlm2ToolParser::new(&test_tools());
assert!(parser.preserve_special_tokens());
}
}