feat: enhance documentation linking with linkcode and relative path resolution

Author: AtsushiSakai

docs/conf.py

@@ -13,6 +13,8 @@
 #
 import os
 import sys
+from pathlib import Path
+
 sys.path.insert(0, os.path.abspath('../'))
 
 
@@ -41,7 +43,7 @@
     'matplotlib.sphinxext.plot_directive',
     'sphinx.ext.autodoc',
     'sphinx.ext.mathjax',
-    'sphinx.ext.viewcode',
+    'sphinx.ext.linkcode',
     'sphinx.ext.napoleon',
     'sphinx.ext.imgconverter',
     'IPython.sphinxext.ipython_console_highlighting',
@@ -192,7 +194,7 @@
 import functools
 
 GITHUB_REPO = "https://github.com/AtsushiSakai/PythonRobotics"
-GITHUB_BRANCH = "main"
+GITHUB_BRANCH = "master"
 
 
 def linkcode_resolve(domain, info):
@@ -210,10 +212,19 @@ def linkcode_resolve(domain, info):
 
     try:
         srcfile = inspect.getsourcefile(obj)
-        srcfile = os.path.relpath(srcfile, start=os.path.dirname(
-            sys.modules[modname].__file__))
+        srcfile = get_relative_path_from_parent(srcfile, "PythonRobotics")
         lineno = inspect.getsourcelines(obj)[1]
     except Exception:
         return None
 
     return f"{GITHUB_REPO}/blob/{GITHUB_BRANCH}/{srcfile}#L{lineno}"
+
+
+def get_relative_path_from_parent(file_path: str, parent_dir: str):
+    path = Path(file_path).resolve()
+
+    try:
+        parent_path = next(p for p in path.parents if p.name == parent_dir)
+        return str(path.relative_to(parent_path))
+    except StopIteration:
+        raise ValueError(f"Parent directory '{parent_dir}' not found in {file_path}")