contrib/fuzz/fuzzutil.h

discovery: avoid wrong detection of multiple branch heads (issue6256)

This fix the code using obsolescence markers to remove "to be obsoleted" heads
during the detection of new head creation from push. The code turned out to not
use the branch information at all. This lead changeset from different branch to
be detected as new head on unrelated branch.

The code fix is actually quite simple. New tests have been added to covers
these cases.

Differential Revision: https://phab.mercurial-scm.org/D8259

#ifndef CONTRIB_FUZZ_FUZZUTIL_H
#define CONTRIB_FUZZ_FUZZUTIL_H
#include <iostream>
#include <memory>
#include <stdint.h>

/* Try and use std::optional, but failing that assume we'll have a
 * workable https://abseil.io/ install on the include path to get
 * their backport of std::optional. */
#ifdef __has_include
#if __has_include(<optional>) && __cplusplus >= 201703L
#include <optional>
#define CONTRIB_FUZZ_HAVE_STD_OPTIONAL
#endif
#endif
#ifdef CONTRIB_FUZZ_HAVE_STD_OPTIONAL
namespace contrib
{
using std::nullopt;
using std::optional;
} /* namespace contrib */
#else
#include "third_party/absl/types/optional.h"
namespace contrib
{
using absl::nullopt;
using absl::optional;
} /* namespace contrib */
#endif

/* set DEBUG to 1 for a few debugging prints, or 2 for a lot */
#define DEBUG 0
#define LOG(level)                                                             \
	if (level <= DEBUG)                                                    \
	std::cout

#endif /* CONTRIB_FUZZ_FUZZUTIL_H */