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-rw-r--r--src/libexpr/eval.cc74
-rw-r--r--src/libexpr/eval.hh23
-rw-r--r--src/libexpr/tests/derived-path.cc65
3 files changed, 162 insertions, 0 deletions
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 679f46153..740a5e677 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -2318,6 +2318,80 @@ StorePath EvalState::coerceToStorePath(const PosIdx pos, Value & v, NixStringCon
}
+std::pair<DerivedPath, std::string_view> EvalState::coerceToDerivedPathUnchecked(const PosIdx pos, Value & v, std::string_view errorCtx)
+{
+ NixStringContext context;
+ auto s = forceString(v, context, pos, errorCtx);
+ auto csize = context.size();
+ if (csize != 1)
+ error(
+ "string '%s' has %d entries in its context. It should only have exactly one entry",
+ s, csize)
+ .withTrace(pos, errorCtx).debugThrow<EvalError>();
+ auto derivedPath = std::visit(overloaded {
+ [&](NixStringContextElem::Opaque && o) -> DerivedPath {
+ return DerivedPath::Opaque {
+ .path = std::move(o.path),
+ };
+ },
+ [&](NixStringContextElem::DrvDeep &&) -> DerivedPath {
+ error(
+ "string '%s' has a context which refers to a complete source and binary closure. This is not supported at this time",
+ s).withTrace(pos, errorCtx).debugThrow<EvalError>();
+ },
+ [&](NixStringContextElem::Built && b) -> DerivedPath {
+ return DerivedPath::Built {
+ .drvPath = std::move(b.drvPath),
+ .outputs = OutputsSpec::Names { std::move(b.output) },
+ };
+ },
+ }, ((NixStringContextElem &&) *context.begin()).raw());
+ return {
+ std::move(derivedPath),
+ std::move(s),
+ };
+}
+
+
+DerivedPath EvalState::coerceToDerivedPath(const PosIdx pos, Value & v, std::string_view errorCtx)
+{
+ auto [derivedPath, s_] = coerceToDerivedPathUnchecked(pos, v, errorCtx);
+ auto s = s_;
+ std::visit(overloaded {
+ [&](const DerivedPath::Opaque & o) {
+ auto sExpected = store->printStorePath(o.path);
+ if (s != sExpected)
+ error(
+ "path string '%s' has context with the different path '%s'",
+ s, sExpected)
+ .withTrace(pos, errorCtx).debugThrow<EvalError>();
+ },
+ [&](const DerivedPath::Built & b) {
+ // TODO need derived path with single output to make this
+ // total. Will add as part of RFC 92 work and then this is
+ // cleaned up.
+ auto output = *std::get<OutputsSpec::Names>(b.outputs).begin();
+
+ auto drv = store->readDerivation(b.drvPath);
+ auto i = drv.outputs.find(output);
+ if (i == drv.outputs.end())
+ throw Error("derivation '%s' does not have output '%s'", store->printStorePath(b.drvPath), output);
+ auto optOutputPath = i->second.path(*store, drv.name, output);
+ // This is testing for the case of CA derivations
+ auto sExpected = optOutputPath
+ ? store->printStorePath(*optOutputPath)
+ : downstreamPlaceholder(*store, b.drvPath, output);
+ if (s != sExpected)
+ error(
+ "string '%s' has context with the output '%s' from derivation '%s', but the string is not the right placeholder for this derivation output. It should be '%s'",
+ s, output, store->printStorePath(b.drvPath), sExpected)
+ .withTrace(pos, errorCtx).debugThrow<EvalError>();
+ }
+ }, derivedPath.raw());
+ return derivedPath;
+}
+
+
bool EvalState::eqValues(Value & v1, Value & v2, const PosIdx pos, std::string_view errorCtx)
{
forceValue(v1, noPos);
diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh
index 3b2164a19..a90ff34c0 100644
--- a/src/libexpr/eval.hh
+++ b/src/libexpr/eval.hh
@@ -21,6 +21,7 @@ namespace nix {
class Store;
class EvalState;
class StorePath;
+struct DerivedPath;
enum RepairFlag : bool;
@@ -473,6 +474,28 @@ public:
*/
StorePath coerceToStorePath(const PosIdx pos, Value & v, NixStringContext & context, std::string_view errorCtx);
+ /**
+ * Part of `coerceToDerivedPath()` without any store IO which is exposed for unit testing only.
+ */
+ std::pair<DerivedPath, std::string_view> coerceToDerivedPathUnchecked(const PosIdx pos, Value & v, std::string_view errorCtx);
+
+ /**
+ * Coerce to `DerivedPath`.
+ *
+ * Must be a string which is either a literal store path or a
+ * "placeholder (see `downstreamPlaceholder()`).
+ *
+ * Even more importantly, the string context must be exactly one
+ * element, which is either a `NixStringContextElem::Opaque` or
+ * `NixStringContextElem::Built`. (`NixStringContextEleme::DrvDeep`
+ * is not permitted).
+ *
+ * The string is parsed based on the context --- the context is the
+ * source of truth, and ultimately tells us what we want, and then
+ * we ensure the string corresponds to it.
+ */
+ DerivedPath coerceToDerivedPath(const PosIdx pos, Value & v, std::string_view errorCtx);
+
public:
/**
diff --git a/src/libexpr/tests/derived-path.cc b/src/libexpr/tests/derived-path.cc
new file mode 100644
index 000000000..8210efef2
--- /dev/null
+++ b/src/libexpr/tests/derived-path.cc
@@ -0,0 +1,65 @@
+#include <nlohmann/json.hpp>
+#include <gtest/gtest.h>
+#include <rapidcheck/gtest.h>
+
+#include "tests/derived-path.hh"
+#include "tests/libexpr.hh"
+
+namespace nix {
+
+// Testing of trivial expressions
+class DerivedPathExpressionTest : public LibExprTest {};
+
+// FIXME: `RC_GTEST_FIXTURE_PROP` isn't calling `SetUpTestSuite` because it is
+// no a real fixture.
+//
+// See https://github.com/emil-e/rapidcheck/blob/master/doc/gtest.md#rc_gtest_fixture_propfixture-name-args
+TEST_F(DerivedPathExpressionTest, force_init)
+{
+}
+
+RC_GTEST_FIXTURE_PROP(
+ DerivedPathExpressionTest,
+ prop_opaque_path_round_trip,
+ (const DerivedPath::Opaque & o))
+{
+ auto * v = state.allocValue();
+ state.mkStorePathString(o.path, *v);
+ auto d = state.coerceToDerivedPath(noPos, *v, "");
+ RC_ASSERT(DerivedPath { o } == d);
+}
+
+// TODO use DerivedPath::Built for parameter once it supports a single output
+// path only.
+
+RC_GTEST_FIXTURE_PROP(
+ DerivedPathExpressionTest,
+ prop_built_path_placeholder_round_trip,
+ (const StorePath & drvPath, const StorePathName & outputName))
+{
+ auto * v = state.allocValue();
+ state.mkOutputString(*v, drvPath, outputName.name, std::nullopt);
+ auto [d, _] = state.coerceToDerivedPathUnchecked(noPos, *v, "");
+ DerivedPath::Built b {
+ .drvPath = drvPath,
+ .outputs = OutputsSpec::Names { outputName.name },
+ };
+ RC_ASSERT(DerivedPath { b } == d);
+}
+
+RC_GTEST_FIXTURE_PROP(
+ DerivedPathExpressionTest,
+ prop_built_path_out_path_round_trip,
+ (const StorePath & drvPath, const StorePathName & outputName, const StorePath & outPath))
+{
+ auto * v = state.allocValue();
+ state.mkOutputString(*v, drvPath, outputName.name, outPath);
+ auto [d, _] = state.coerceToDerivedPathUnchecked(noPos, *v, "");
+ DerivedPath::Built b {
+ .drvPath = drvPath,
+ .outputs = OutputsSpec::Names { outputName.name },
+ };
+ RC_ASSERT(DerivedPath { b } == d);
+}
+
+} /* namespace nix */