fuzz: exercise a little more revlog code

Differential Revision: https://phab.mercurial-scm.org/D7032

contrib/fuzz/revlog.cc

@@ -1,57 +1,62 b''
 #include <Python.h>
 #include <assert.h>
 #include <stdlib.h>
 #include <unistd.h>
 
 #include <string>
 
 #include "pyutil.h"
 
 extern "C" {
 
 static PyCodeObject *code;
 
 extern "C" int LLVMFuzzerInitialize(int *argc, char ***argv)
 {
 	contrib::initpy(*argv[0]);
 	code = (PyCodeObject *)Py_CompileString(R"py(
 from parsers import parse_index2
 for inline in (True, False):
     try:
         index, cache = parse_index2(data, inline)
         index.slicechunktodensity(list(range(len(index))), 0.5, 262144)
+        index.stats()
+        index.findsnapshots({}, 0)
+        10 in index
         for rev in range(len(index)):
+            index.reachableroots(0, [len(index)-1], [rev])
             node = index[rev][7]
             partial = index.shortest(node)
             index.partialmatch(node[:partial])
+            index.deltachain(rev, None, True)
     except Exception as e:
         pass
         # uncomment this print if you're editing this Python code
         # to debug failures.
         # print e
 )py",
 	                                        "fuzzer", Py_file_input);
 	return 0;
 }
 
 int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)
 {
 	// Don't allow fuzzer inputs larger than 60k, since we'll just bog
 	// down and not accomplish much.
 	if (Size > 60000) {
 		return 0;
 	}
 	PyObject *text =
 	    PyBytes_FromStringAndSize((const char *)Data, (Py_ssize_t)Size);
 	PyObject *locals = PyDict_New();
 	PyDict_SetItemString(locals, "data", text);
 	PyObject *res = PyEval_EvalCode(code, contrib::pyglobals(), locals);
 	if (!res) {
 		PyErr_Print();
 	}
 	Py_XDECREF(res);
 	Py_DECREF(locals);
 	Py_DECREF(text);
 	return 0; // Non-zero return values are reserved for future use.
 }
 }