[Rust Frontend] Fix Qwen parser auto-detection (#51169)

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
Co-authored-by: Bugen Zhao <i@bugenzhao.com>
Signed-off-by: Sage Ahrac <sagiahrak@gmail.com>

rust/src/chat/src/parser/reasoning/mod.rs

@@ -85,7 +85,8 @@ impl ReasoningParserFactory {
             .register_pattern("deepseek-v3", names::DEEPSEEK_V3)
             .register_pattern("gemma-4", names::GEMMA4)
             .register_pattern("gemma4", names::GEMMA4)
-            .register_pattern("qwen", names::QWEN3)
+            .register_pattern("qwq", names::DEEPSEEK_R1)
+            .register_pattern("qwen3", names::QWEN3)
             .register_pattern("glm-5", names::GLM45)
             .register_pattern("glm-4.7", names::GLM45)
             .register_pattern("glm-4.6", names::GLM45)

rust/src/chat/src/parser/reasoning/tests.rs

@@ -37,6 +37,23 @@ fn factory_resolves_deepseek_v4_to_qwen3_alias() {
     );
 }
 
+#[test]
+fn factory_distinguishes_qwen_model_families() {
+    let factory = ReasoningParserFactory::new();
+    assert_eq!(
+        factory.resolve_name_for_model("Qwen/QwQ-32B"),
+        Some(names::DEEPSEEK_R1)
+    );
+    assert_eq!(
+        factory.resolve_name_for_model("Qwen/Qwen3-8B"),
+        Some(names::QWEN3)
+    );
+    assert_eq!(
+        factory.resolve_name_for_model("Qwen/Qwen2.5-0.5B-Instruct"),
+        None
+    );
+}
+
 #[test]
 fn factory_routes_step3p5_models_to_dedicated_parser() {
     let factory = ReasoningParserFactory::new();

rust/src/chat/src/parser/tool/mod.rs

@@ -94,9 +94,10 @@ impl ToolParserFactory {
             .register_pattern("mistral-", names::MISTRAL)
             .register_pattern("mixtral-", names::MISTRAL)
             .register_pattern("qwen3-coder", names::QWEN3_CODER)
-            .register_pattern("qwen2.5-coder", names::QWEN3_CODER)
             .register_pattern("qwen3.5", names::QWEN3_CODER)
-            .register_pattern("qwen", names::QWEN3_XML)
+            .register_pattern("qwq", names::HERMES)
+            .register_pattern("qwen2.5", names::HERMES)
+            .register_pattern("qwen3", names::QWEN3_XML)
             .register_pattern("hermes", names::HERMES)
             .register_pattern("hy3", names::HY_V3)
             .register_pattern("hy_v3", names::HY_V3)

rust/src/chat/src/parser/tool/tests.rs

@@ -80,22 +80,45 @@ fn factory_creates_registered_parser_for_model() {
     factory.create_for_model("my-fake-model-v1", &[]).unwrap();
 }
 
+#[test]
+fn factory_distinguishes_qwen_tool_formats() {
+    let factory = ToolParserFactory::new();
+
+    for (model, expected) in [
+        ("Qwen/Qwen3.5-0.8B", Some(names::QWEN3_CODER)),
+        ("Qwen/Qwen3-0.6B", Some(names::QWEN3_XML)),
+        ("Qwen/Qwen3-Coder-30B", Some(names::QWEN3_CODER)),
+        ("Qwen/QwQ-32B", Some(names::HERMES)),
+        ("Qwen/Qwen2.5-0.5B-Instruct", Some(names::HERMES)),
+        ("Qwen/Qwen2-1.5B-Instruct", None),
+    ] {
+        assert_eq!(factory.resolve_name_for_model(model), expected, "{model}");
+    }
+}
+
+#[test]
+fn factory_parses_qwen2_5_coder_template_with_hermes() {
+    let factory = ToolParserFactory::new();
+    let tool_call = r#"<tool_call>
+{"name":"get_weather","arguments":{"location":"Tokyo"}}
+</tool_call>"#;
+
+    let mut parser = factory.create_for_model("Qwen/Qwen2.5-Coder-7B-Instruct", &[]).unwrap();
+    let mut output = ToolParserOutput::default();
+    parser.parse_into(tool_call, &mut output).unwrap();
+    output.append(parser.finish().unwrap());
+    let output = output.coalesce();
+
+    assert!(output.normal_text().is_empty());
+    assert_eq!(output.calls().len(), 1);
+    assert_eq!(output.calls()[0].name.as_deref(), Some("get_weather"));
+    assert_eq!(output.calls()[0].arguments, r#"{"location":"Tokyo"}"#);
+}
+
 #[test]
 fn factory_new_resolves_default_patterns() {
     let factory = ToolParserFactory::new();
 
-    assert_eq!(
-        factory.resolve_name_for_model("Qwen/Qwen3.5-0.8B"),
-        Some(names::QWEN3_CODER)
-    );
-    assert_eq!(
-        factory.resolve_name_for_model("Qwen/Qwen3-0.6B"),
-        Some(names::QWEN3_XML)
-    );
-    assert_eq!(
-        factory.resolve_name_for_model("Qwen/Qwen3-Coder-30B"),
-        Some(names::QWEN3_CODER)
-    );
     assert_eq!(
         factory.resolve_name_for_model("meta-llama-4-maverick"),
         Some(names::LLAMA4_JSON)