Files
lix/lix/libutil/deprecated-features.cc
T
eldritch horrors c3929c78f3 libutil: disallow enum serialization by default
allow opting in to serialization as integers via a trait type instead,
and add string-list serializers for the feature flag set enumerations.

fixes #738

Change-Id: I2746eb5ef1f15c01b4e681f9ba1615b6c6e64f44
2025-03-25 10:44:52 +01:00

122 lines
3.4 KiB
C++

#include "lix/libutil/deprecated-features.hh"
#include "lix/libutil/json.hh"
#include "lix/libutil/strings.hh"
namespace nix {
struct DeprecatedFeatureDetails
{
DeprecatedFeature tag;
std::string_view name;
std::string_view description;
};
/**
* If two different PRs both add a deprecated feature, and we just
* used a number for this, we *woudln't* get merge conflict and the
* counter will be incremented once instead of twice, causing a build
* failure.
*
* By instead defining this instead as a dummy bottom deprecated
* feature, we do not have this issue.
*/
constexpr size_t numDepFeatures = static_cast<size_t>(Dep::NumDepFeatures);
constexpr std::array<DeprecatedFeatureDetails, numDepFeatures> depFeatureDetails = {{
#include "deprecated-features-impl.gen.inc"
}};
static_assert(
[]() constexpr {
for (auto [index, feature] : enumerate(depFeatureDetails))
if (index != (size_t)feature.tag)
return false;
return true;
}(),
"array order does not match enum tag order");
const std::optional<DeprecatedFeature> parseDeprecatedFeature(const std::string_view & name)
{
using ReverseDepMap = std::map<std::string_view, DeprecatedFeature>;
static std::unique_ptr<ReverseDepMap> reverseDepMap = []() {
auto reverseDepMap = std::make_unique<ReverseDepMap>();
for (auto & depFeature : depFeatureDetails)
(*reverseDepMap)[depFeature.name] = depFeature.tag;
return reverseDepMap;
}();
if (auto feature = get(*reverseDepMap, name))
return *feature;
else
return std::nullopt;
}
std::string_view showDeprecatedFeature(const DeprecatedFeature tag)
{
assert((size_t)tag < depFeatureDetails.size());
return depFeatureDetails[(size_t)tag].name;
}
JSON documentDeprecatedFeatures()
{
StringMap res;
for (auto & depFeature : depFeatureDetails)
res[std::string { depFeature.name }] =
trim(stripIndentation(depFeature.description));
return (JSON) res;
}
DeprecatedFeatures parseDeprecatedFeatures(const std::set<std::string> & rawFeatures)
{
DeprecatedFeatures res{};
for (auto & rawFeature : rawFeatures)
if (auto feature = parseDeprecatedFeature(rawFeature))
res = res | *feature;
return res;
}
MissingDeprecatedFeature::MissingDeprecatedFeature(DeprecatedFeature feature)
: Error("Lix feature '%1%' is deprecated and should not be used anymore; use '--extra-deprecated-features %1%' to disable this error", showDeprecatedFeature(feature))
, missingFeature(feature)
{}
std::ostream & operator <<(std::ostream & str, const DeprecatedFeature & feature)
{
return str << showDeprecatedFeature(feature);
}
void to_json(JSON & j, const DeprecatedFeature & feature)
{
j = showDeprecatedFeature(feature);
}
void from_json(const JSON & j, DeprecatedFeature & feature)
{
const std::string input = j;
const auto parsed = parseDeprecatedFeature(input);
if (parsed.has_value())
feature = *parsed;
else
throw Error("Unknown deprecated feature '%s' in JSON input", input);
}
void to_json(JSON & j, const DeprecatedFeatures & f)
{
StringSet res;
for (auto & depFeature : depFeatureDetails) {
if ((f & depFeature.tag) == (DeprecatedFeatures{} | depFeature.tag)) {
res.emplace(depFeature.name);
}
}
j = res;
}
void from_json(const JSON & j, DeprecatedFeatures & f)
{
f = parseDeprecatedFeatures(j.get<StringSet>());
}
}