Python: Fix os.path.samefile modeling

Author: RasmusWL

python/ql/lib/semmle/python/frameworks/Stdlib.qll

@@ -959,13 +959,18 @@ private module StdlibPrivate {
     }
   }
 
-  /** A call to `os.path.samefile` will raise an exception if an `os.stat()` call on either pathname fails. */
+  /**
+   * A call to `os.path.samefile` will raise an exception if an `os.stat()` call on either pathname fails.
+   *
+   * See https://docs.python.org/3.10/library/os.path.html#os.path.samefile
+   */
   private class OsPathSamefileCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
     OsPathSamefileCall() { this = OS::path().getMember("samefile").getACall() }
 
     override DataFlow::Node getAPathArgument() {
       result in [
-          this.getArg(0), this.getArgByName("path1"), this.getArg(1), this.getArgByName("path2")
+          // note that the f1/f2 names doesn't match the documentation, but is what actually works (tested on 3.8.10)
+          this.getArg(0), this.getArgByName("f1"), this.getArg(1), this.getArgByName("f2")
         ]
     }
   }

python/ql/test/library-tests/frameworks/stdlib/FileSystemAccess.py

@@ -48,6 +48,9 @@ def through_function(open_file):
 os.path.ismount("path")  # $ getAPathArgument="path"
 os.path.ismount(path="path")  # $ getAPathArgument="path"
 
+os.path.samefile("f1", "f2")  # $ getAPathArgument="f1" getAPathArgument="f2"
+os.path.samefile(f1="f1", f2="f2")  # $ getAPathArgument="f1" getAPathArgument="f2"
+
 # actual os.path implementations
 import posixpath
 import ntpath
@@ -269,4 +272,4 @@ def test_fspath():
 shutil.copystat(src="src", dst="dst") # $ getAPathArgument="src" getAPathArgument="dst"
 
 shutil.disk_usage("path") # $ getAPathArgument="path"
-shutil.disk_usage(path="path") # $ getAPathArgument="path"
+shutil.disk_usage(path="path") # $ getAPathArgument="path"