wip: attempt to handle github PR builds

docs/source/conf.py

@@ -96,6 +96,19 @@ def setup(app):
     generate_examples()
 
 
+def get_repo_base_and_branch(pr_number):
+    url = f"https://api.github.com/repos/vllm-project/vllm/pulls/{pr_number}"
+    response = requests.get(url)
+    if response.status_code == 200:
+        data = response.json()
+        base = data['base']['repo']['full_name']
+        branch = data['base']['ref']
+        return base, branch
+    else:
+        logger.error(f"Failed to fetch PR details: {response.status_code}")
+        return None, None
+
+
 def linkcode_resolve(domain, info):
     if domain != 'py':
         return None
@@ -104,14 +117,26 @@ def linkcode_resolve(domain, info):
     filename = info['module'].replace('.', '/')
     module = info['module']
     try:
+        # try to determine the correct file and line number to link to
         obj = sys.modules[module]
         for part in info['fullname'].split('.'):
             obj = getattr(obj, part)
         lineno = inspect.getsourcelines(obj)[1]
         filename = (inspect.getsourcefile(obj)
                     or f"{filename}.py").split("vllm/", 1)[1]
+
+        if filename.startswith("checkouts/"):
+            # a PR build on readthedocs
+            pr_number = filename.split("/")[1]
+            filename = filename.split("/", 2)[2]
+            base, branch = get_repo_base_and_branch(pr_number)
+            if base and branch:
+                return f"https://github.com/{base}/blob/{branch}/{filename}#L{lineno}"
+
+        # Otherwise, link to the source file on the main branch
         return f"https://github.com/vllm-project/vllm/blob/main/{filename}#L{lineno}"
     except Exception:
+        # last resort fallback, just try to point to the correct file on main
         return f"https://github.com/vllm-project/vllm/blob/main/{filename}.py"