Support source file suffix detection (#21)

CHANGELOG.rst

@@ -1,6 +1,12 @@
 Changelog
 =========
 
+0.2.4
+-----
+
+- Support source file suffix detection
+  `#21 <https://github.com/jdillard/sphinx-llms-txt/pull/21>`_
+
 0.2.3
 -----
 

sphinx_llms_txt/__init__.py

@@ -12,7 +12,7 @@ from .manager import LLMSFullManager
 from .processor import DocumentProcessor
 from .writer import FileWriter
 
-__version__ = "0.2.3"
+__version__ = "0.2.4"
 
 # Export classes needed by tests
 __all__ = [

sphinx_llms_txt/collector.py

@@ -3,7 +3,7 @@ Document collector module for sphinx-llms-txt.
 """
 
 import fnmatch
-from typing import Any, Dict, List
+from typing import Any, Dict, List, Tuple
 
 from sphinx.environment import BuildEnvironment
 from sphinx.util import logging
@@ -19,6 +19,7 @@ class DocumentCollector:
         self.master_doc: str = None
         self.env: BuildEnvironment = None
         self.config: Dict[str, Any] = {}
+        self.app = None
 
     def set_master_doc(self, master_doc: str):
         """Set the master document name."""
@@ -37,8 +38,73 @@ class DocumentCollector:
         """Set configuration options."""
         self.config = config
 
-    def get_page_order(self) -> List[str]:
+    def set_app(self, app):
-        """Get the correct page order from the toctree structure."""
+        """Set the Sphinx application reference."""
+        self.app = app
+
+    def _get_source_suffixes(self):
+        """Get all valid source file suffixes from Sphinx configuration.
+
+        Returns:
+            list: List of source file suffixes (e.g., ['.rst', '.md', '.txt'])
+        """
+        if not self.app:
+            return [".rst"]  # Default fallback
+
+        source_suffix = self.app.config.source_suffix
+
+        if isinstance(source_suffix, dict):
+            return list(source_suffix.keys())
+        elif isinstance(source_suffix, list):
+            return source_suffix
+        else:
+            return [source_suffix]  # String format
+
+    def _get_docname_suffix(self, docname: str, sources_dir) -> str:
+        """
+        Determine the source suffix for a given docname by checking which
+        file exists.
+
+        Args:
+            docname: The document name to check
+            sources_dir: Path to the _sources directory
+
+        Returns:
+            The source suffix if found, or None if no matching file exists
+        """
+        if not sources_dir or not sources_dir.exists():
+            return None
+
+        # Get the source link suffix from Sphinx config
+        source_link_suffix = ""
+        if self.app and hasattr(self.app.config, "html_sourcelink_suffix"):
+            source_link_suffix = self.app.config.html_sourcelink_suffix
+            # Handle empty string case specially
+            if source_link_suffix == "":
+                source_link_suffix = ""  # Keep it empty
+            elif not source_link_suffix.startswith("."):
+                source_link_suffix = "." + source_link_suffix
+
+        # Get the source file suffixes from Sphinx config
+        source_suffixes = self._get_source_suffixes()
+
+        # Try to find the source file with any of the valid source suffixes
+        for src_suffix in source_suffixes:
+            candidate_file = sources_dir / f"{docname}{src_suffix}{source_link_suffix}"
+            if candidate_file.exists():
+                return src_suffix
+
+        return None
+
+    def get_page_order(self, sources_dir=None) -> List[Tuple[str, str]]:
+        """Get the correct page order from the toctree structure.
+
+        Args:
+            sources_dir: Optional path to _sources directory for suffix detection
+
+        Returns:
+            List of tuples (docname, source_suffix) in toctree order
+        """
         if not self.env or not self.master_doc:
             return []
 
@@ -52,9 +118,12 @@ class DocumentCollector:
 
             visited.add(docname)
 
-            # Add the current document
+            # Add the current document with its suffix
-            if docname not in page_order:
+            if docname not in [doc for doc, _ in page_order]:
-                page_order.append(docname)
+                suffix = None
+                if sources_dir:
+                    suffix = self._get_docname_suffix(docname, sources_dir)
+                page_order.append((docname, suffix))
 
             # Check for toctree entries in this document
             try:
@@ -101,22 +170,33 @@ class DocumentCollector:
 
         # Add any remaining documents not in the toctree (sorted)
         if hasattr(self.env, "all_docs"):
+            processed_docnames = {doc for doc, _ in page_order}
             remaining = sorted(
-                [doc for doc in self.env.all_docs.keys() if doc not in page_order]
+                [
+                    doc
+                    for doc in self.env.all_docs.keys()
+                    if doc not in processed_docnames
+                ]
             )
-            page_order.extend(remaining)
+            for docname in remaining:
+                suffix = None
+                if sources_dir:
+                    suffix = self._get_docname_suffix(docname, sources_dir)
+                page_order.append((docname, suffix))
 
         return page_order
 
-    def filter_excluded_pages(self, page_order: List[str]) -> List[str]:
+    def filter_excluded_pages(
+        self, page_order: List[Tuple[str, str]]
+    ) -> List[Tuple[str, str]]:
         """Filter out excluded pages from the page order."""
         exclude_patterns = self.config.get("llms_txt_exclude")
         if exclude_patterns:
             return [
-                page
+                (docname, suffix)
-                for page in page_order
+                for docname, suffix in page_order
                 if not any(
-                    self._match_exclude_pattern(page, pattern)
+                    self._match_exclude_pattern(docname, pattern)
                     for pattern in exclude_patterns
                 )
             ]

sphinx_llms_txt/manager.py

@@ -56,6 +56,7 @@ class LLMSFullManager:
     def set_app(self, app: Sphinx):
         """Set the Sphinx application reference."""
         self.app = app
+        self.collector.set_app(app)
         if self.writer:
             self.writer.app = app
 
@@ -69,23 +70,7 @@ class LLMSFullManager:
         self.processor = DocumentProcessor(self.config, srcdir)
         self.writer = FileWriter(self.config, outdir, self.app)
 
-        # Get the correct page order
+        # Find sources directory first so we can pass it to get_page_order
-        page_order = self.collector.get_page_order()
-
-        if not page_order:
-            logger.warning(
-                "Could not determine page order, skipping llms-full creation"
-            )
-            return
-
-        # Apply exclusion filter if configured
-        page_order = self.collector.filter_excluded_pages(page_order)
-
-        # Determine output file name and location
-        output_filename = self.config.get("llms_txt_full_filename")
-        output_path = Path(outdir) / output_filename
-
-        # Find sources directory
         sources_dir = None
         possible_sources = [
             Path(outdir) / "_sources",
@@ -104,6 +89,22 @@ class LLMSFullManager:
             )
             return
 
+        # Get the correct page order with source suffixes
+        page_order = self.collector.get_page_order(sources_dir)
+
+        if not page_order:
+            logger.warning(
+                "Could not determine page order, skipping llms-full creation"
+            )
+            return
+
+        # Apply exclusion filter if configured
+        page_order = self.collector.filter_excluded_pages(page_order)
+
+        # Determine output file name and location
+        output_filename = self.config.get("llms_txt_full_filename")
+        output_path = Path(outdir) / output_filename
+
         # Log discovered files and page order
         logger.debug(f"sphinx-llms-txt: Page order (after exclusion): {page_order}")
 
@@ -115,8 +116,19 @@ class LLMSFullManager:
         # Create a mapping from docnames to source files
         docname_to_file = {}
 
-        # Process each docname in the page order
+        # Get the source link suffix from Sphinx config
-        for docname in page_order:
+        source_link_suffix = (
+            self.app.config.html_sourcelink_suffix if self.app else ".txt"
+        )
+
+        # Handle empty string case specially
+        if source_link_suffix == "":
+            source_link_suffix = ""  # Keep it empty
+        elif not source_link_suffix.startswith("."):
+            source_link_suffix = "." + source_link_suffix
+
+        # Process each (docname, suffix) in the page order
+        for docname, src_suffix in page_order:
             # Skip excluded pages
             if exclude_patterns and any(
                 self.collector._match_exclude_pattern(docname, pattern)
@@ -124,15 +136,19 @@ class LLMSFullManager:
             ):
                 continue
 
-            # Construct expected source file path directly from docname
+            # Build the source file path directly using the known suffix
-            source_file = sources_dir / f"{docname}.rst.txt"
+            if src_suffix:
-
+                source_file = sources_dir / f"{docname}{src_suffix}{source_link_suffix}"
-            if source_file.exists():
+                if source_file.exists():
-                docname_to_file[docname] = source_file
+                    docname_to_file[docname] = source_file
+                else:
+                    logger.warning(
+                        f"sphinx-llms-txt: Source file not found for: {docname}."
+                        f"Expected: {docname}{src_suffix}{source_link_suffix}"
+                    )
             else:
                 logger.warning(
-                    f"sphinx-llm-txt: Source file not found for: {docname}. Expected"
+                    f"sphinx-llms-txt: No source suffix determined for: {docname}"
-                    f" at {source_file}"
                 )
 
         # Generate content
@@ -144,7 +160,7 @@ class LLMSFullManager:
         max_lines = self.config.get("llms_txt_full_max_size")
         abort_due_to_max_lines = False
 
-        for docname in page_order:
+        for docname, _ in page_order:
             if docname in docname_to_file:
                 file_path = docname_to_file[docname]
                 content, line_count = self._read_source_file(file_path, docname)
@@ -179,14 +195,19 @@ class LLMSFullManager:
                     total_line_count += line_count
             else:
                 logger.warning(
-                    f"sphinx-llm-txt: Source file not found for: {docname}. Check that"
+                    f"sphinx-llms-txt: Source file not found for: {docname}. Check that"
-                    f" the file exists at _sources/{docname}.rst.txt"
+                    f" file exists at _sources/{docname}[suffix]{source_link_suffix}"
                 )
 
         # Add any remaining files (in alphabetical order) that aren't in the page order
         if not abort_due_to_max_lines:
-            # Get all .rst.txt files in the _sources directory
+            # Get all source files in the _sources directory using configured suffixes
-            all_source_files = list(sources_dir.glob("**/*.rst.txt"))
+            source_suffixes = self._get_source_suffixes()
+            all_source_files = []
+            for src_suffix in source_suffixes:
+                glob_pattern = f"**/*{src_suffix}{source_link_suffix}"
+                all_source_files.extend(sources_dir.glob(glob_pattern))
+
             processed_paths = set(file.resolve() for file in docname_to_file.values())
 
             # Find files that haven't been processed yet
@@ -204,11 +225,18 @@ class LLMSFullManager:
                 )
 
             for file_path in remaining_source_files:
-                # Extract docname from path by removing the .rst.txt extension
+                # Extract docname from path by removing the source and link suffixes
                 rel_path = str(file_path.relative_to(sources_dir))
-                if rel_path.endswith(".rst.txt"):
+                docname = None
-                    docname = rel_path[:-8]  # Remove .rst.txt extension
+
-                else:
+                # Try each source suffix to find which one this file uses
+                for src_suffix in source_suffixes:
+                    combined_suffix = f"{src_suffix}{source_link_suffix}"
+                    if rel_path.endswith(combined_suffix):
+                        docname = rel_path[: -len(combined_suffix)]  # Remove suffix
+                        break
+
+                if docname is None:
                     continue
 
                 # Skip excluded docnames
@@ -237,7 +265,7 @@ class LLMSFullManager:
             max_lines is not None and total_line_count > max_lines
         ):
             logger.warning(
-                f"sphinx-llm-txt: Max line limit ({max_lines}) exceeded:"
+                f"sphinx-llms-txt: Max line limit ({max_lines}) exceeded:"
                 f" {total_line_count} > {max_lines}. "
                 f"Not creating llms-full.txt file."
             )
@@ -304,5 +332,23 @@ class LLMSFullManager:
             return content_str, line_count + 1
 
         except Exception as e:
-            logger.error(f"sphinx-llm-txt: Error reading source file {file_path}: {e}")
+            logger.error(f"sphinx-llms-txt: Error reading source file {file_path}: {e}")
             return "", 0
+
+    def _get_source_suffixes(self):
+        """Get all valid source file suffixes from Sphinx configuration.
+
+        Returns:
+            list: List of source file suffixes (e.g., ['.rst', '.md', '.txt'])
+        """
+        if not self.app:
+            return [".rst"]  # Default fallback
+
+        source_suffix = self.app.config.source_suffix
+
+        if isinstance(source_suffix, dict):
+            return list(source_suffix.keys())
+        elif isinstance(source_suffix, list):
+            return source_suffix
+        else:
+            return [source_suffix]  # String format

sphinx_llms_txt/writer.py

@@ -3,7 +3,7 @@ File writer module for sphinx-llms-txt.
 """
 
 from pathlib import Path
-from typing import Any, Dict, List
+from typing import Any, Dict, List, Tuple, Union
 
 from sphinx.application import Sphinx
 from sphinx.util import logging
@@ -42,19 +42,19 @@ class FileWriter:
             )
             return True
         except Exception as e:
-            logger.error(f"sphinx-llm-txt: Error writing combined sources file: {e}")
+            logger.error(f"sphinx-llms-txt: Error writing combined sources file: {e}")
             return False
 
     def write_verbose_info_to_file(
         self,
-        page_order: List[str],
+        page_order: Union[List[str], List[Tuple[str, str]]],
         page_titles: Dict[str, str],
         total_line_count: int = 0,
     ) -> bool:
         """Write summary information to the llms.txt file.
 
         Args:
-            page_order: Ordered list of document names
+            page_order: Ordered list of document names or (docname, suffix) tuples
             page_titles: Dictionary mapping docnames to titles
             total_line_count: Total number of lines in the combined content
 
@@ -100,7 +100,12 @@ class FileWriter:
                 if not base_url.endswith("/"):
                     base_url += "/"
 
-                for docname in page_order:
+                for item in page_order:
+                    # Handle both old format (str) and new format (tuple)
+                    if isinstance(item, tuple):
+                        docname, _ = item
+                    else:
+                        docname = item
                     title = page_titles.get(docname, docname)
                     f.write(f"- [{title}]({base_url}{docname}.html)\n")
 

tests/test_llms_txt.py

@@ -334,3 +334,396 @@ def test_write_verbose_info_with_baseurl(tmp_path):
 
     assert "- [Home Page](https://example.org/index.html)" in content
     assert "- [About Us](https://example.org/about.html)" in content
+
+
+def test_get_source_suffixes_with_dict():
+    """Test _get_source_suffixes method with dict source_suffix."""
+    from sphinx_llms_txt.manager import LLMSFullManager
+
+    # Mock Sphinx app with dict source_suffix
+    class MockApp:
+        class Config:
+            source_suffix = {".rst": None, ".md": None, ".txt": None}
+
+        config = Config()
+
+    manager = LLMSFullManager()
+    manager.set_app(MockApp())
+
+    suffixes = manager._get_source_suffixes()
+    assert set(suffixes) == {".rst", ".md", ".txt"}
+
+
+def test_get_source_suffixes_with_list():
+    """Test _get_source_suffixes method with list source_suffix."""
+    from sphinx_llms_txt.manager import LLMSFullManager
+
+    # Mock Sphinx app with list source_suffix
+    class MockApp:
+        class Config:
+            source_suffix = [".rst", ".md"]
+
+        config = Config()
+
+    manager = LLMSFullManager()
+    manager.set_app(MockApp())
+
+    suffixes = manager._get_source_suffixes()
+    assert suffixes == [".rst", ".md"]
+
+
+def test_get_source_suffixes_with_string():
+    """Test _get_source_suffixes method with string source_suffix."""
+    from sphinx_llms_txt.manager import LLMSFullManager
+
+    # Mock Sphinx app with string source_suffix
+    class MockApp:
+        class Config:
+            source_suffix = ".rst"
+
+        config = Config()
+
+    manager = LLMSFullManager()
+    manager.set_app(MockApp())
+
+    suffixes = manager._get_source_suffixes()
+    assert suffixes == [".rst"]
+
+
+def test_get_source_suffixes_no_app():
+    """Test _get_source_suffixes method with no app set."""
+    from sphinx_llms_txt.manager import LLMSFullManager
+
+    manager = LLMSFullManager()
+
+    suffixes = manager._get_source_suffixes()
+    assert suffixes == [".rst"]  # Default fallback
+
+
+def test_html_sourcelink_suffix_default():
+    """Test html_sourcelink_suffix defaults to .txt when no app is set."""
+    import tempfile
+
+    from sphinx_llms_txt.manager import LLMSFullManager
+
+    manager = LLMSFullManager()
+    manager.set_config(
+        {
+            "llms_txt_full_filename": "test.txt",
+            "llms_txt_exclude": [],
+            "llms_txt_directives": [],
+        }
+    )
+
+    # Create a temporary directory structure
+    with tempfile.TemporaryDirectory() as tmpdir:
+        outdir = f"{tmpdir}/build"
+        srcdir = f"{tmpdir}/source"
+        sources_dir = f"{outdir}/_sources"
+
+        # Create directories
+        import os
+
+        os.makedirs(sources_dir, exist_ok=True)
+        os.makedirs(srcdir, exist_ok=True)
+
+        # Create a test source file with default .txt suffix
+        test_file = f"{sources_dir}/index.rst.txt"
+        with open(test_file, "w") as f:
+            f.write("Test content")
+
+        # Mock env with minimal required attributes
+        class MockEnv:
+            all_docs = {"index": None}
+            titles = {
+                "index": type("TitleNode", (), {"astext": lambda: "Test Title"})()
+            }
+            toctree_includes = {}
+
+        manager.set_env(MockEnv())
+        manager.set_master_doc("index")
+
+        # Test that it uses .txt as the default suffix
+        manager.combine_sources(outdir, srcdir)
+
+        # Verify the file was found and processed (check if output file exists)
+        output_file = f"{outdir}/test.txt"
+        assert os.path.exists(output_file)
+
+
+def test_html_sourcelink_suffix_custom():
+    """Test html_sourcelink_suffix uses custom value from Sphinx config."""
+    import tempfile
+
+    from sphinx_llms_txt.manager import LLMSFullManager
+
+    # Mock Sphinx app with custom html_sourcelink_suffix
+    class MockApp:
+        class Config:
+            html_sourcelink_suffix = "source"
+            source_suffix = ".rst"
+
+        config = Config()
+
+    manager = LLMSFullManager()
+    manager.set_app(MockApp())
+    manager.set_config(
+        {
+            "llms_txt_full_filename": "test.txt",
+            "llms_txt_exclude": [],
+            "llms_txt_directives": [],
+        }
+    )
+
+    # Create a temporary directory structure
+    with tempfile.TemporaryDirectory() as tmpdir:
+        outdir = f"{tmpdir}/build"
+        srcdir = f"{tmpdir}/source"
+        sources_dir = f"{outdir}/_sources"
+
+        # Create directories
+        import os
+
+        os.makedirs(sources_dir, exist_ok=True)
+        os.makedirs(srcdir, exist_ok=True)
+
+        # Create a test source file with custom .source suffix
+        test_file = f"{sources_dir}/index.rst.source"
+        with open(test_file, "w") as f:
+            f.write("Test content")
+
+        # Mock env with minimal required attributes
+        class MockEnv:
+            all_docs = {"index": None}
+            titles = {
+                "index": type("TitleNode", (), {"astext": lambda: "Test Title"})()
+            }
+            toctree_includes = {}
+
+        manager.set_env(MockEnv())
+        manager.set_master_doc("index")
+
+        # Test that it uses .source as the custom suffix
+        manager.combine_sources(outdir, srcdir)
+
+        # Verify the file was found and processed
+        output_file = f"{outdir}/test.txt"
+        assert os.path.exists(output_file)
+
+
+def test_html_sourcelink_suffix_with_dot():
+    """Test html_sourcelink_suffix adds dot if missing."""
+    import tempfile
+
+    from sphinx_llms_txt.manager import LLMSFullManager
+
+    # Mock Sphinx app with html_sourcelink_suffix without leading dot
+    class MockApp:
+        class Config:
+            html_sourcelink_suffix = "src"  # No leading dot
+            source_suffix = ".rst"
+
+        config = Config()
+
+    manager = LLMSFullManager()
+    manager.set_app(MockApp())
+    manager.set_config(
+        {
+            "llms_txt_full_filename": "test.txt",
+            "llms_txt_exclude": [],
+            "llms_txt_directives": [],
+        }
+    )
+
+    # Create a temporary directory structure
+    with tempfile.TemporaryDirectory() as tmpdir:
+        outdir = f"{tmpdir}/build"
+        srcdir = f"{tmpdir}/source"
+        sources_dir = f"{outdir}/_sources"
+
+        # Create directories
+        import os
+
+        os.makedirs(sources_dir, exist_ok=True)
+        os.makedirs(srcdir, exist_ok=True)
+
+        # Create a test source file with .src suffix (dot should be added automatically)
+        test_file = f"{sources_dir}/index.rst.src"
+        with open(test_file, "w") as f:
+            f.write("Test content")
+
+        # Mock env with minimal required attributes
+        class MockEnv:
+            all_docs = {"index": None}
+            titles = {
+                "index": type("TitleNode", (), {"astext": lambda: "Test Title"})()
+            }
+            toctree_includes = {}
+
+        manager.set_env(MockEnv())
+        manager.set_master_doc("index")
+
+        # Test that it adds the dot and finds the file
+        manager.combine_sources(outdir, srcdir)
+
+        # Verify the file was found and processed
+        output_file = f"{outdir}/test.txt"
+        assert os.path.exists(output_file)
+
+
+def test_mixed_source_file_formats():
+    """Test handling of mixed source file formats (.rst, .md, .txt)."""
+    import tempfile
+
+    from sphinx_llms_txt.manager import LLMSFullManager
+
+    # Mock Sphinx app with multiple source suffixes
+    class MockApp:
+        class Config:
+            html_sourcelink_suffix = ".txt"
+            source_suffix = {".rst": None, ".md": None, ".txt": None}
+
+        config = Config()
+
+    manager = LLMSFullManager()
+    manager.set_app(MockApp())
+    manager.set_config(
+        {
+            "llms_txt_full_filename": "test.txt",
+            "llms_txt_exclude": [],
+            "llms_txt_directives": [],
+        }
+    )
+
+    # Create a temporary directory structure
+    with tempfile.TemporaryDirectory() as tmpdir:
+        outdir = f"{tmpdir}/build"
+        srcdir = f"{tmpdir}/source"
+        sources_dir = f"{outdir}/_sources"
+
+        # Create directories
+        import os
+
+        os.makedirs(sources_dir, exist_ok=True)
+        os.makedirs(srcdir, exist_ok=True)
+
+        # Create test source files with different formats
+        files_to_create = [
+            f"{sources_dir}/page1.rst.txt",
+            f"{sources_dir}/page2.md.txt",
+            f"{sources_dir}/page3.txt.txt",
+        ]
+
+        for test_file in files_to_create:
+            with open(test_file, "w") as f:
+                f.write(f"Content for {os.path.basename(test_file)}")
+
+        # Mock env with all documents
+        class MockEnv:
+            all_docs = {"page1": None, "page2": None, "page3": None}
+            titles = {
+                "page1": type("TitleNode", (), {"astext": lambda: "Page 1"})(),
+                "page2": type("TitleNode", (), {"astext": lambda: "Page 2"})(),
+                "page3": type("TitleNode", (), {"astext": lambda: "Page 3"})(),
+            }
+            toctree_includes = {}
+
+        manager.set_env(MockEnv())
+        manager.set_master_doc("page1")
+
+        # Test that all file formats are found and processed
+        manager.combine_sources(outdir, srcdir)
+
+        # Verify the output file was created and contains content from all formats
+        output_file = f"{outdir}/test.txt"
+        assert os.path.exists(output_file)
+
+        with open(output_file, "r") as f:
+            content = f.read()
+
+        # Should contain content from all three files
+        assert "Content for page1.rst.txt" in content
+        assert "Content for page2.md.txt" in content
+        assert "Content for page3.txt.txt" in content
+
+
+def test_source_suffix_detection_priority():
+    """Test source suffix detection tries formats in correct order for docnames."""
+    import tempfile
+
+    from sphinx_llms_txt.manager import LLMSFullManager
+
+    # Mock Sphinx app with ordered source suffixes
+    class MockApp:
+        class Config:
+            html_sourcelink_suffix = ".txt"
+            source_suffix = [".rst", ".md"]  # rst has priority over md
+
+        config = Config()
+
+    manager = LLMSFullManager()
+    manager.set_app(MockApp())
+    manager.set_config(
+        {
+            "llms_txt_full_filename": "test.txt",
+            "llms_txt_exclude": [],
+            "llms_txt_directives": [],
+        }
+    )
+
+    # Create a temporary directory structure
+    with tempfile.TemporaryDirectory() as tmpdir:
+        outdir = f"{tmpdir}/build"
+        srcdir = f"{tmpdir}/source"
+        sources_dir = f"{outdir}/_sources"
+
+        # Create directories
+        import os
+
+        os.makedirs(sources_dir, exist_ok=True)
+        os.makedirs(srcdir, exist_ok=True)
+
+        # Create both .rst and .md versions of the same document
+        # Only create files for the specific docname "index"
+        rst_file = f"{sources_dir}/index.rst.txt"
+        md_file = f"{sources_dir}/index.md.txt"
+
+        with open(rst_file, "w") as f:
+            f.write("RST content for index")
+
+        with open(md_file, "w") as f:
+            f.write("Markdown content for index")
+
+        # Mock env with only the index document
+        class MockEnv:
+            all_docs = {"index": None}
+            titles = {
+                "index": type("TitleNode", (), {"astext": lambda: "Index Page"})()
+            }
+            toctree_includes = {"index": []}
+
+        manager.set_env(MockEnv())
+        manager.set_master_doc("index")
+
+        # Test the priority behavior
+        manager.combine_sources(outdir, srcdir)
+
+        # Check that output file was created
+        output_file = f"{outdir}/test.txt"
+        assert os.path.exists(output_file)
+
+        with open(output_file, "r") as f:
+            content = f.read()
+
+        # The system should prefer RST over MD for the "index" docname
+        # But since both files exist and the second phase adds remaining files,
+        # both will be included. The test verifies that RST appears first
+        # (indicating it was found first in the priority order)
+        assert "RST content for index" in content
+
+        # Find positions to verify order
+        rst_pos = content.find("RST content for index")
+        md_pos = content.find("Markdown content for index")
+
+        # RST should come before MD (due to priority in toctree processing)
+        assert rst_pos < md_pos, "RST content should appear before MD content"