fix(mineru): honor dataset language in figure prompts (#18188)

### Summary

Closes #17885.

MinerU figure enrichment now passes the resolved dataset language to
`vision_llm_figure_describe_prompt`. Missing and empty language values
use `English`, matching the other figure-description paths.

This change is limited to MinerU. PR #18021 already fixed the Mistral
path.

deepdoc/parser/mineru_parser.py

@@ -876,7 +876,7 @@ class MinerUParser(RAGFlowPdfParser):
     def _transfer_to_tables(self, outputs: list[dict[str, Any]]):
         return []
 
-    def _enhance_images_with_vlm(self, outputs: list[dict[str, Any]], vision_model, callback: Optional[Callable] = None):
+    def _enhance_images_with_vlm(self, outputs: list[dict[str, Any]], vision_model, callback: Optional[Callable] = None, language: str = "English"):
         """Generate semantic descriptions for image blocks via the tenant's
         VISION model, mirroring deepdoc's VisionFigureParser. Each
         IMAGE block with a readable img_path gets a ``vlm_description``
@@ -894,7 +894,7 @@ class MinerUParser(RAGFlowPdfParser):
         if callback:
             callback(0.78, f"[MinerU] Generating VLM descriptions for {len(image_jobs)} images...")
 
-        prompt = vision_llm_figure_describe_prompt()
+        prompt = vision_llm_figure_describe_prompt(language=language or "English")
 
         def worker(idx, item):
             try:
@@ -935,7 +935,7 @@ class MinerUParser(RAGFlowPdfParser):
         created_tmp_dir = False
 
         parser_cfg = kwargs.get("parser_config", {})
-        lang = parser_cfg.get("mineru_lang") or kwargs.get("lang", "English")
+        lang = parser_cfg.get("mineru_lang") or kwargs.get("lang") or "English"
         mineru_lang_code = LANGUAGE_TO_MINERU_MAP.get(lang, "ch")  # Defaults to Chinese if not matched
         mineru_method_raw_str = parser_cfg.get("mineru_parse_method", "auto")
         enable_formula = parser_cfg.get("mineru_formula_enable", True)
@@ -998,7 +998,7 @@ class MinerUParser(RAGFlowPdfParser):
             vision_model = kwargs.get("vision_model")
             if vision_model is not None:
                 try:
-                    self._enhance_images_with_vlm(outputs, vision_model, callback=callback)
+                    self._enhance_images_with_vlm(outputs, vision_model, callback=callback, language=lang)
                 except Exception as e:
                     self.logger.warning(f"[MinerU] VLM image enhancement failed: {e}. Continuing without descriptions.")
 

test/unit_test/deepdoc/parser/test_mineru_parser.py

@@ -4,8 +4,11 @@ import sys
 from io import BytesIO
 from pathlib import Path
 from types import ModuleType
+from unittest.mock import Mock
 import json
 
+import pytest
+
 
 def _load_mineru_parser(monkeypatch):
     repo_root = Path(__file__).resolve().parents[4]
@@ -39,6 +42,73 @@ def _load_mineru_parser(monkeypatch):
     return module
 
 
+@pytest.mark.p1
+@pytest.mark.parametrize(
+    ("language", "expected_language"),
+    [
+        ("Japanese", "Japanese"),
+        ("", "English"),
+        (None, "English"),
+    ],
+)
+def test_enhance_images_with_vlm_passes_dataset_language_to_prompt(monkeypatch, tmp_path, language, expected_language):
+    module = _load_mineru_parser(monkeypatch)
+    parser = module.MinerUParser()
+    image_path = tmp_path / "figure.png"
+    module.Image.new("RGB", (1, 1)).save(image_path)
+
+    picture_module = ModuleType("rag.app.picture")
+    picture_module.vision_llm_chunk = Mock(return_value="description")
+    prompt = Mock(return_value="prompt")
+    generator_module = ModuleType("rag.prompts.generator")
+    generator_module.vision_llm_figure_describe_prompt = prompt
+    monkeypatch.setitem(sys.modules, "rag.app.picture", picture_module)
+    monkeypatch.setitem(sys.modules, "rag.prompts.generator", generator_module)
+
+    outputs = [{"type": module.MinerUContentType.IMAGE, "img_path": str(image_path)}]
+    parser._enhance_images_with_vlm(outputs, vision_model=object(), language=language)
+
+    prompt.assert_called_once_with(language=expected_language)
+    assert outputs[0]["vlm_description"] == "description"
+
+
+@pytest.mark.p1
+@pytest.mark.parametrize(
+    ("language", "expected_language"),
+    [
+        ("Japanese", "Japanese"),
+        ("", "English"),
+        (None, "English"),
+    ],
+)
+def test_parse_pdf_forwards_normalized_dataset_language_to_image_enhancement(monkeypatch, tmp_path, language, expected_language):
+    module = _load_mineru_parser(monkeypatch)
+    parser = module.MinerUParser()
+    pdf_path = tmp_path / "document.pdf"
+    pdf_path.write_bytes(b"%PDF-1.4 fake")
+    output_dir = tmp_path / "output"
+    vision_model = object()
+
+    monkeypatch.setattr(module, "extract_pdf_outlines", Mock(return_value=[]))
+    monkeypatch.setattr(parser, "__images__", Mock())
+    monkeypatch.setattr(parser, "_run_mineru", Mock(return_value=output_dir))
+    monkeypatch.setattr(parser, "_read_output", Mock(return_value=[]))
+    enhance = Mock()
+    monkeypatch.setattr(parser, "_enhance_images_with_vlm", enhance)
+
+    language_kwargs = {} if language is None else {"lang": language}
+    parser.parse_pdf(
+        filepath=pdf_path,
+        binary=None,
+        output_dir=str(output_dir),
+        delete_output=False,
+        vision_model=vision_model,
+        **language_kwargs,
+    )
+
+    enhance.assert_called_once_with([], vision_model, callback=None, language=expected_language)
+
+
 def test_sanitize_section_text_removes_escaped_html_tags(monkeypatch):
     module = _load_mineru_parser(monkeypatch)
     text = "<table><tr><td>Alpha</td><td>Beta</td></tr></table>"

test/unit_test/rag/app/test_vision_language_callers.py

@@ -125,3 +125,30 @@ def test_mistral_ocr_forwards_language_to_parser(monkeypatch):
     assert tables == []
     assert returned_parser is parser
     assert parser.parse_pdf.call_args.kwargs["lang"] == "Japanese"
+
+
+@pytest.mark.p1
+def test_mineru_forwards_dataset_language_to_parser(monkeypatch):
+    parser = Mock()
+    parser.parse_pdf.return_value = (["section"], [])
+    ocr_model = Mock(mdl=parser)
+    monkeypatch.setattr(naive, "resolve_model_config", Mock(return_value={"llm_name": "mineru"}))
+    monkeypatch.setattr(naive, "LLMBundle", Mock(return_value=ocr_model))
+
+    sections, tables, returned_parser = naive.by_mineru(
+        "document.pdf",
+        binary=b"pdf",
+        from_page=2,
+        to_page=5,
+        lang="Japanese",
+        callback=lambda *_args, **_kwargs: None,
+        parse_method="raw",
+        mineru_llm_name="mineru",
+        tenant_id="tenant-id",
+        vision_model=object(),
+    )
+
+    assert sections == ["section"]
+    assert tables == []
+    assert returned_parser is parser
+    assert parser.parse_pdf.call_args.kwargs["lang"] == "Japanese"