lix/src/libexpr/get-drvs.cc

523 lines
17 KiB
C++

#include "lix/libexpr/get-drvs.hh"
#include "lix/libexpr/eval-inline.hh"
#include "lix/libstore/derivations.hh"
#include "lix/libexpr/eval.hh"
#include "lix/libstore/store-api.hh"
#include "lix/libstore/path-with-outputs.hh"
#include <cstring>
#include <regex>
namespace nix {
DrvInfo::DrvInfo(EvalState & state, std::string attrPath, Bindings * attrs)
: state(&state), attrs(attrs), attrPath(std::move(attrPath))
{
}
DrvInfo::DrvInfo(EvalState & state, ref<Store> store, const std::string & drvPathWithOutputs)
: state(&state), attrs(nullptr), attrPath("")
{
auto [drvPath, selectedOutputs] = parsePathWithOutputs(*store, drvPathWithOutputs);
this->drvPath = drvPath;
auto drv = store->derivationFromPath(drvPath);
name = drvPath.name();
if (selectedOutputs.size() > 1)
throw Error("building more than one derivation output is not supported, in '%s'", drvPathWithOutputs);
outputName =
selectedOutputs.empty()
? getOr(drv.env, "outputName", "out")
: *selectedOutputs.begin();
auto i = drv.outputs.find(outputName);
if (i == drv.outputs.end())
throw Error("derivation '%s' does not have output '%s'", store->printStorePath(drvPath), outputName);
auto & [outputName, output] = *i;
outPath = {output.path(*store, drv.name, outputName)};
}
std::string DrvInfo::queryName()
{
if (name == "" && attrs) {
auto i = attrs->find(state->sName);
if (i == attrs->end()) state->error<TypeError>("derivation name missing").debugThrow();
name = state->forceStringNoCtx(*i->value, noPos, "while evaluating the 'name' attribute of a derivation");
}
return name;
}
std::string DrvInfo::querySystem()
{
if (system == "" && attrs) {
auto i = attrs->find(state->sSystem);
system = i == attrs->end() ? "unknown" : state->forceStringNoCtx(*i->value, i->pos, "while evaluating the 'system' attribute of a derivation");
}
return system;
}
std::optional<StorePath> DrvInfo::queryDrvPath()
{
if (!drvPath && attrs) {
Bindings::iterator i = attrs->find(state->sDrvPath);
NixStringContext context;
if (i == attrs->end())
drvPath = {std::nullopt};
else
drvPath = {state->coerceToStorePath(i->pos, *i->value, context, "while evaluating the 'drvPath' attribute of a derivation")};
}
return drvPath.value_or(std::nullopt);
}
StorePath DrvInfo::requireDrvPath()
{
if (auto drvPath = queryDrvPath())
return *drvPath;
throw Error("derivation does not contain a 'drvPath' attribute");
}
StorePath DrvInfo::queryOutPath()
{
if (!outPath && attrs) {
Bindings::iterator i = attrs->find(state->sOutPath);
NixStringContext context;
if (i != attrs->end())
outPath = state->coerceToStorePath(i->pos, *i->value, context, "while evaluating the output path of a derivation");
}
if (!outPath)
throw UnimplementedError("CA derivations are not yet supported");
return *outPath;
}
void DrvInfo::fillOutputs(bool withPaths)
{
auto fillDefault = [&]() {
std::optional<StorePath> outPath = std::nullopt;
if (withPaths) {
outPath.emplace(this->queryOutPath());
}
this->outputs.emplace("out", outPath);
};
// lol. lmao even.
if (this->attrs == nullptr) {
fillDefault();
return;
}
Attr * outputs = this->attrs->get(this->state->sOutputs);
if (outputs == nullptr) {
fillDefault();
return;
}
// NOTE(Qyriad): I don't think there is any codepath that can cause this to error.
this->state->forceList(
*outputs->value,
outputs->pos,
"while evaluating the 'outputs' attribute of a derivation"
);
for (auto [idx, elem] : enumerate(outputs->value->listItems())) {
// NOTE(Qyriad): This error should be *extremely* rare in practice.
// It is impossible to construct with `stdenv.mkDerivation`,
// `builtins.derivation`, or even `derivationStrict`. As far as we can tell,
// it is only possible by overriding a derivation attrset already created by
// one of those with `//` to introduce the failing `outputs` entry.
auto errMsg = fmt("while evaluating output %d of a derivation", idx);
std::string_view outputName = state->forceStringNoCtx(
*elem,
outputs->pos,
errMsg
);
if (withPaths) {
// Find the attr with this output's name...
Attr * out = this->attrs->get(this->state->symbols.create(outputName));
if (out == nullptr) {
// FIXME: throw error?
continue;
}
// Meanwhile we couldn't figure out any circumstances
// that cause this to error.
state->forceAttrs(*out->value, outputs->pos, errMsg);
// ...and evaluate its `outPath` attribute.
Attr * outPath = out->value->attrs->get(this->state->sOutPath);
if (outPath == nullptr) {
continue;
// FIXME: throw error?
}
NixStringContext context;
// And idk what could possibly cause this one to error
// that wouldn't error before here.
auto storePath = state->coerceToStorePath(
outPath->pos,
*outPath->value,
context,
errMsg
);
this->outputs.emplace(outputName, storePath);
} else {
this->outputs.emplace(outputName, std::nullopt);
}
}
}
DrvInfo::Outputs DrvInfo::queryOutputs(bool withPaths, bool onlyOutputsToInstall)
{
// If we haven't already cached the outputs set, then do so now.
if (outputs.empty()) {
// FIXME: this behavior seems kind of busted, since whether or not this
// DrvInfo will have paths is forever determined by the *first* call to
// this function??
fillOutputs(withPaths);
}
// Things that operate on derivations like packages, like `nix-env` and `nix build`,
// allow derivations to specify which outputs should be used in those user-facing
// cases if the user didn't specify an output explicitly.
// If the caller just wanted all the outputs for this derivation, though,
// then we're done here.
if (!onlyOutputsToInstall || !attrs)
return outputs;
// Regardless of `meta.outputsToInstall`, though, you can select into a derivation
// output by its attribute, e.g. `pkgs.lix.dev`, which (lol?) sets the magic
// attribute `outputSpecified = true`, and changes the `outputName` attr to the
// explicitly selected-into output.
if (Attr * outSpecAttr = attrs->get(state->sOutputSpecified)) {
bool outputSpecified = this->state->forceBool(
*outSpecAttr->value,
outSpecAttr->pos,
"while evaluating the 'outputSpecified' attribute of a derivation"
);
if (outputSpecified) {
auto maybeOut = outputs.find(queryOutputName());
if (maybeOut == outputs.end()) {
throw Error("derivation does not have output '%s'", queryOutputName());
}
return Outputs{*maybeOut};
}
}
/* Check for `meta.outputsToInstall` and return `outputs` reduced to that. */
const Value * outTI = queryMeta("outputsToInstall");
if (!outTI) return outputs;
auto errMsg = Error("this derivation has bad 'meta.outputsToInstall'");
/* ^ this shows during `nix-env -i` right under the bad derivation */
if (!outTI->isList()) throw errMsg;
Outputs result;
for (auto elem : outTI->listItems()) {
if (elem->type() != nString) throw errMsg;
auto out = outputs.find(elem->string.s);
if (out == outputs.end()) throw errMsg;
result.insert(*out);
}
return result;
}
std::string DrvInfo::queryOutputName()
{
if (outputName == "" && attrs) {
Bindings::iterator i = attrs->find(state->sOutputName);
outputName = i != attrs->end() ? state->forceStringNoCtx(*i->value, noPos, "while evaluating the output name of a derivation") : "";
}
return outputName;
}
Bindings * DrvInfo::getMeta()
{
if (meta) return meta;
if (!attrs) return 0;
Bindings::iterator a = attrs->find(state->sMeta);
if (a == attrs->end()) return 0;
state->forceAttrs(*a->value, a->pos, "while evaluating the 'meta' attribute of a derivation");
meta = a->value->attrs;
return meta;
}
StringSet DrvInfo::queryMetaNames()
{
StringSet res;
if (!getMeta()) return res;
for (auto & i : *meta)
res.emplace(state->symbols[i.name]);
return res;
}
bool DrvInfo::checkMeta(Value & v)
{
state->forceValue(v, v.determinePos(noPos));
if (v.type() == nList) {
for (auto elem : v.listItems())
if (!checkMeta(*elem)) return false;
return true;
}
else if (v.type() == nAttrs) {
Bindings::iterator i = v.attrs->find(state->sOutPath);
if (i != v.attrs->end()) return false;
for (auto & i : *v.attrs)
if (!checkMeta(*i.value)) return false;
return true;
}
else return v.type() == nInt || v.type() == nBool || v.type() == nString ||
v.type() == nFloat;
}
Value * DrvInfo::queryMeta(const std::string & name)
{
if (!getMeta()) return 0;
Bindings::iterator a = meta->find(state->symbols.create(name));
if (a == meta->end() || !checkMeta(*a->value)) return 0;
return a->value;
}
std::string DrvInfo::queryMetaString(const std::string & name)
{
Value * v = queryMeta(name);
if (!v || v->type() != nString) return "";
return v->string.s;
}
NixInt DrvInfo::queryMetaInt(const std::string & name, NixInt def)
{
Value * v = queryMeta(name);
if (!v) return def;
if (v->type() == nInt) return v->integer;
if (v->type() == nString) {
/* Backwards compatibility with before we had support for
integer meta fields. */
if (auto n = string2Int<NixInt::Inner>(v->string.s))
return NixInt{*n};
}
return def;
}
NixFloat DrvInfo::queryMetaFloat(const std::string & name, NixFloat def)
{
Value * v = queryMeta(name);
if (!v) return def;
if (v->type() == nFloat) return v->fpoint;
if (v->type() == nString) {
/* Backwards compatibility with before we had support for
float meta fields. */
if (auto n = string2Float<NixFloat>(v->string.s))
return *n;
}
return def;
}
bool DrvInfo::queryMetaBool(const std::string & name, bool def)
{
Value * v = queryMeta(name);
if (!v) return def;
if (v->type() == nBool) return v->boolean;
if (v->type() == nString) {
/* Backwards compatibility with before we had support for
Boolean meta fields. */
if (strcmp(v->string.s, "true") == 0) return true;
if (strcmp(v->string.s, "false") == 0) return false;
}
return def;
}
void DrvInfo::setMeta(const std::string & name, Value * v)
{
getMeta();
auto attrs = state->buildBindings(1 + (meta ? meta->size() : 0));
auto sym = state->symbols.create(name);
if (meta)
for (auto i : *meta)
if (i.name != sym)
attrs.insert(i);
if (v) attrs.insert(sym, v);
meta = attrs.finish();
}
/* Cache for already considered attrsets. */
typedef std::set<Bindings *> Done;
/* The result boolean indicates whether it makes sense
for the caller to recursively search for derivations in `v'. */
static bool getDerivation(EvalState & state, Value & v,
const std::string & attrPath, DrvInfos & drvs,
bool ignoreAssertionFailures)
{
try {
state.forceValue(v, v.determinePos(noPos));
if (!state.isDerivation(v)) return true;
DrvInfo drv(state, attrPath, v.attrs);
drv.queryName();
drvs.push_back(drv);
return false;
} catch (AssertionError & e) {
if (ignoreAssertionFailures) return false;
throw;
}
}
std::optional<DrvInfo> getDerivation(EvalState & state, Value & v,
bool ignoreAssertionFailures)
{
DrvInfos drvs;
getDerivation(state, v, "", drvs, ignoreAssertionFailures);
if (drvs.size() != 1) return {};
return std::move(drvs.front());
}
static std::string addToPath(const std::string & s1, const std::string & s2)
{
return s1.empty() ? s2 : s1 + "." + s2;
}
static std::regex attrRegex("[A-Za-z_][A-Za-z0-9-_+]*");
/* Evaluate value `v'. If it evaluates to a set of type `derivation',
then put information about it in `drvs'. If it evaluates to a different
kind of set recurse (unless it's already in `done'). */
static void getDerivations(EvalState & state, Value & vIn,
const std::string & pathPrefix, Bindings & autoArgs,
DrvInfos & drvs, Done & done,
bool ignoreAssertionFailures)
{
Value v;
state.autoCallFunction(autoArgs, vIn, v);
bool shouldRecurse = getDerivation(state, v, pathPrefix, drvs, ignoreAssertionFailures);
if (!shouldRecurse) {
// We're done here.
return;
}
if (v.type() == nList) {
// NOTE we can't really deduplicate here because small lists don't have stable addresses
// and can cause spurious duplicate detections due to v being on the stack.
for (auto [n, elem] : enumerate(v.listItems())) {
std::string joinedAttrPath = addToPath(pathPrefix, fmt("%d", n));
bool shouldRecurse = getDerivation(state, *elem, joinedAttrPath, drvs, ignoreAssertionFailures);
if (shouldRecurse) {
getDerivations(
state,
*elem,
joinedAttrPath,
autoArgs,
drvs,
done,
ignoreAssertionFailures
);
}
}
return;
} else if (v.type() != nAttrs) {
state.error<TypeError>(
"expression was expected to be a derivation or collection of derivations, but instead was %s",
showType(v.type(), true)
).debugThrow();
}
/* Dont consider sets we've already seen, e.g. y in
`rec { x.d = derivation {...}; y = x; }`. */
auto const &[_, didInsert] = done.insert(v.attrs);
if (!didInsert) {
return;
}
// FIXME: what the fuck???
/* !!! undocumented hackery to support combining channels in
nix-env.cc. */
bool combineChannels = v.attrs->find(state.symbols.create("_combineChannels")) != v.attrs->end();
/* Consider the attributes in sorted order to get more
deterministic behaviour in nix-env operations (e.g. when
there are names clashes between derivations, the derivation
bound to the attribute with the "lower" name should take
precedence). */
for (auto & attr : v.attrs->lexicographicOrder(state.symbols)) {
debug("evaluating attribute '%1%'", state.symbols[attr->name]);
// FIXME: only consider attrs with identifier-like names?? Why???
if (!std::regex_match(std::string(state.symbols[attr->name]), attrRegex)) {
continue;
}
std::string joinedAttrPath = addToPath(pathPrefix, state.symbols[attr->name]);
if (combineChannels) {
getDerivations(state, *attr->value, joinedAttrPath, autoArgs, drvs, done, ignoreAssertionFailures);
} else if (getDerivation(state, *attr->value, joinedAttrPath, drvs, ignoreAssertionFailures)) {
/* If the value of this attribute is itself a set,
should we recurse into it? => Only if it has a
`recurseForDerivations = true' attribute. */
if (attr->value->type() == nAttrs) {
Attr * recurseForDrvs = attr->value->attrs->get(state.sRecurseForDerivations);
if (recurseForDrvs == nullptr) {
continue;
}
bool shouldRecurse = state.forceBool(
*recurseForDrvs->value,
attr->pos,
fmt("while evaluating the '%s' attribute", Magenta("recurseForDerivations"))
);
if (!shouldRecurse) {
continue;
}
getDerivations(
state,
*attr->value,
joinedAttrPath,
autoArgs,
drvs,
done,
ignoreAssertionFailures
);
}
}
}
}
void getDerivations(EvalState & state, Value & v, const std::string & pathPrefix,
Bindings & autoArgs, DrvInfos & drvs, bool ignoreAssertionFailures)
{
Done done;
getDerivations(state, v, pathPrefix, autoArgs, drvs, done, ignoreAssertionFailures);
}
}