From e37f5483e8ad054c8f10244841fb617024b6805d Mon Sep 17 00:00:00 2001
From: Jared Dillard <jared.dillard@gmail.com>
Date: Sun, 22 Mar 2026 15:55:35 -0700
Subject: [PATCH] Fix double extension in llms.txt URLs when source suffix
 matches sourcelink suffix

---
 CHANGELOG.rst               |  6 ++++++
 sphinx_llms_txt/__init__.py |  2 +-
 sphinx_llms_txt/writer.py   |  8 ++++++-
 tests/test_uri_template.py  | 42 +++++++++++++++++++++++++++++++++++++
 4 files changed, 56 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 83059ae..552ae99 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -1,6 +1,12 @@
 Changelog
 =========
 
+0.7.2
+-----
+
+- Fix double extension in llms.txt URLs when source suffix matches sourcelink suffix
+  `#63 <https://github.com/jdillard/sphinx-llms-txt/issues/63>`_
+
 0.7.1
 -----
 
diff --git a/sphinx_llms_txt/__init__.py b/sphinx_llms_txt/__init__.py
index c64762b..def4ad5 100644
--- a/sphinx_llms_txt/__init__.py
+++ b/sphinx_llms_txt/__init__.py
@@ -21,7 +21,7 @@ from .manager import LLMSFullManager
 from .processor import DocumentProcessor
 from .writer import FileWriter
 
-__version__ = "0.7.1"
+__version__ = "0.7.2"
 
 # Export classes needed by tests
 __all__ = [
diff --git a/sphinx_llms_txt/writer.py b/sphinx_llms_txt/writer.py
index 44b9279..9a3ef2a 100644
--- a/sphinx_llms_txt/writer.py
+++ b/sphinx_llms_txt/writer.py
@@ -163,11 +163,17 @@ class FileWriter:
 
                     title = page_titles.get(docname, docname)
 
+                    # Avoid duplicate extensions when suffix matches
+                    # sourcelink_suffix (e.g., both are ".txt")
+                    effective_sourcelink_suffix = sourcelink_suffix
+                    if suffix and suffix == sourcelink_suffix:
+                        effective_sourcelink_suffix = ""
+
                     uri = uri_template.format(
                         base_url=base_url,
                         docname=docname,
                         suffix=suffix or "",
-                        sourcelink_suffix=sourcelink_suffix,
+                        sourcelink_suffix=effective_sourcelink_suffix,
                     )
 
                     f.write(f"- [{title}]({uri})\n")
diff --git a/tests/test_uri_template.py b/tests/test_uri_template.py
index f5ad243..c6773cd 100644
--- a/tests/test_uri_template.py
+++ b/tests/test_uri_template.py
@@ -132,6 +132,48 @@ def test_uri_template_custom(tmp_path):
     assert "- [Home Page](https://example.com/raw/index.rst)" in content
 
 
+def test_uri_template_no_double_extension_when_suffix_matches_sourcelink(tmp_path):
+    """Test that .txt suffix + .txt sourcelink_suffix doesn't produce .txt.txt URLs."""
+    build_dir = tmp_path / "build"
+    build_dir.mkdir()
+
+    sources_dir = build_dir / "_sources"
+    sources_dir.mkdir()
+
+    class MockApp:
+        class Config:
+            html_sourcelink_suffix = ".txt"
+
+        config = Config()
+
+    config = {
+        "llms_txt_file": True,
+        "llms_txt_filename": "llms.txt",
+        "html_baseurl": "https://example.com",
+    }
+    writer = FileWriter(config, str(build_dir), MockApp())
+
+    page_titles = {
+        "index": "Home Page",
+        "contents": "Table of Contents",
+    }
+
+    # .txt source files — suffix matches sourcelink_suffix
+    page_order = [("index", ".txt"), ("contents", ".txt")]
+
+    writer.write_verbose_info_to_file(page_order, page_titles, 0, sources_dir)
+
+    verbose_file = build_dir / "llms.txt"
+    with open(verbose_file, "r", encoding="utf-8") as f:
+        content = f.read()
+
+    # Should NOT have double .txt.txt extension
+    assert ".txt.txt" not in content
+    # Should have single .txt extension
+    assert "- [Home Page](https://example.com/_sources/index.txt)" in content
+    assert "- [Table of Contents](https://example.com/_sources/contents.txt)" in content
+
+
 def test_uri_template_invalid_fallback(tmp_path):
     """
     Test that invalid template falls back to default sources template when