parsers: drop one extra argument to PyErr_Format GCC gave the following warning during `make local`: mercurial/cext/parsers.c: In function 'dirstate_item_from_v1_data': mercurial/cext/parsers.c:413:30: warning: too many arguments for format [-Wformat-extra-args] 413 | "unknown state: `%c` (%d, %d, %d)", state, mode, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ To reproduce, you might need to add the -Wformat-extra-args flag, because it isn't present for me when building for the default python3. But I can see this warning while simply building 6.1 with `make PYTHON=python2 clean local`. I don't think this NULL was useful, because other instances of PyErr_Format() don't have any NULLs as the final argument, but keep in mind that I don't know python's C API.

--- a/mercurial/cext/parsers.c	Fri Jun 03 17:39:58 2022 +0200
+++ b/mercurial/cext/parsers.c	Mon Jun 06 13:58:32 2022 +0400
@@ -374,7 +374,7 @@
 	} else {
 		PyErr_Format(PyExc_RuntimeError,
 		             "unknown state: `%c` (%d, %d, %d)", state, mode,
-		             size, mtime, NULL);
+		             size, mtime);
 		Py_DECREF(t);
 		return NULL;
 	}