libexpr: Make getAttr a member function of EvalState

src/libexpr/eval.cc

@@ -2243,6 +2243,16 @@ bool EvalState::forceBool(Value & v, const PosIdx pos, std::string_view errorCtx
     return v.boolean();
 }
 
+Bindings::const_iterator EvalState::getAttr(Symbol attrSym, const Bindings * attrSet, std::string_view errorCtx)
+{
+    auto value = attrSet->find(attrSym);
+    if (value == attrSet->end()) {
+        error<TypeError>("attribute '%s' missing", symbols[attrSym])
+            .withTrace(noPos, errorCtx)
+            .debugThrow();
+    }
+    return value;
+}
 
 bool EvalState::isFunctor(const Value & fun) const
 {

src/libexpr/include/nix/expr/eval.hh

@@ -542,6 +542,11 @@ public:
     std::string_view forceString(Value & v, NixStringContext & context, const PosIdx pos, std::string_view errorCtx, const ExperimentalFeatureSettings & xpSettings = experimentalFeatureSettings);
     std::string_view forceStringNoCtx(Value & v, const PosIdx pos, std::string_view errorCtx);
 
+    /**
+     * Get attribute from an attribute set and throw an error if it doesn't exist.
+     */
+    Bindings::const_iterator getAttr(Symbol attrSym, const Bindings * attrSet, std::string_view errorCtx);
+
     template<typename... Args>
     [[gnu::noinline]]
     void addErrorTrace(Error & e, const Args & ... formatArgs) const;

src/libexpr/primops.cc

@@ -670,26 +670,12 @@ struct CompareValues
 
 typedef std::list<Value *, gc_allocator<Value *>> ValueList;
 
-
-static Bindings::const_iterator getAttr(
-    EvalState & state,
-    Symbol attrSym,
-    const Bindings * attrSet,
-    std::string_view errorCtx)
-{
-    auto value = attrSet->find(attrSym);
-    if (value == attrSet->end()) {
-        state.error<TypeError>("attribute '%s' missing", state.symbols[attrSym]).withTrace(noPos, errorCtx).debugThrow();
-    }
-    return value;
-}
-
 static void prim_genericClosure(EvalState & state, const PosIdx pos, Value * * args, Value & v)
 {
     state.forceAttrs(*args[0], noPos, "while evaluating the first argument passed to builtins.genericClosure");
 
     /* Get the start set. */
-    auto startSet = getAttr(state, state.sStartSet, args[0]->attrs(), "in the attrset passed as argument to builtins.genericClosure");
+    auto startSet = state.getAttr(state.sStartSet, args[0]->attrs(), "in the attrset passed as argument to builtins.genericClosure");
 
     state.forceList(*startSet->value, noPos, "while evaluating the 'startSet' attribute passed as argument to builtins.genericClosure");
 
@@ -703,7 +689,7 @@ static void prim_genericClosure(EvalState & state, const PosIdx pos, Value * * a
     }
 
     /* Get the operator. */
-    auto op = getAttr(state, state.sOperator, args[0]->attrs(), "in the attrset passed as argument to builtins.genericClosure");
+    auto op = state.getAttr(state.sOperator, args[0]->attrs(), "in the attrset passed as argument to builtins.genericClosure");
     state.forceFunction(*op->value, noPos, "while evaluating the 'operator' attribute passed as argument to builtins.genericClosure");
 
     /* Construct the closure by applying the operator to elements of
@@ -720,7 +706,7 @@ static void prim_genericClosure(EvalState & state, const PosIdx pos, Value * * a
 
         state.forceAttrs(*e, noPos, "while evaluating one of the elements generated by (or initially passed to) builtins.genericClosure");
 
-        auto key = getAttr(state, state.sKey, e->attrs(), "in one of the attrsets generated by (or initially passed to) builtins.genericClosure");
+        auto key = state.getAttr(state.sKey, e->attrs(), "in one of the attrsets generated by (or initially passed to) builtins.genericClosure");
         state.forceValue(*key->value, noPos);
 
         if (!doneKeys.insert(key->value).second) continue;
@@ -1203,7 +1189,7 @@ static void prim_derivationStrict(EvalState & state, const PosIdx pos, Value * *
     auto attrs = args[0]->attrs();
 
     /* Figure out the name first (for stack backtraces). */
-    auto nameAttr = getAttr(state, state.sName, attrs, "in the attrset passed as argument to builtins.derivationStrict");
+    auto nameAttr = state.getAttr(state.sName, attrs, "in the attrset passed as argument to builtins.derivationStrict");
 
     std::string drvName;
     try {
@@ -1893,7 +1879,7 @@ static void prim_findFile(EvalState & state, const PosIdx pos, Value * * args, V
         if (i != v2->attrs()->end())
             prefix = state.forceStringNoCtx(*i->value, pos, "while evaluating the `prefix` attribute of an element of the list passed to builtins.findFile");
 
-        i = getAttr(state, state.sPath, v2->attrs(), "in an element of the __nixPath");
+        i = state.getAttr(state.sPath, v2->attrs(), "in an element of the __nixPath");
 
         NixStringContext context;
         auto path = state.coerceToString(pos, *i->value, context,
@@ -2782,8 +2768,7 @@ void prim_getAttr(EvalState & state, const PosIdx pos, Value * * args, Value & v
 {
     auto attr = state.forceStringNoCtx(*args[0], pos, "while evaluating the first argument passed to builtins.getAttr");
     state.forceAttrs(*args[1], pos, "while evaluating the second argument passed to builtins.getAttr");
-    auto i = getAttr(
+    auto i = state.getAttr(
-        state,
         state.symbols.create(attr),
         args[1]->attrs(),
         "in the attribute set under consideration"
@@ -2973,13 +2958,13 @@ static void prim_listToAttrs(EvalState & state, const PosIdx pos, Value * * args
     for (auto v2 : args[0]->listItems()) {
         state.forceAttrs(*v2, pos, "while evaluating an element of the list passed to builtins.listToAttrs");
 
-        auto j = getAttr(state, state.sName, v2->attrs(), "in a {name=...; value=...;} pair");
+        auto j = state.getAttr(state.sName, v2->attrs(), "in a {name=...; value=...;} pair");
 
         auto name = state.forceStringNoCtx(*j->value, j->pos, "while evaluating the `name` attribute of an element of the list passed to builtins.listToAttrs");
 
         auto sym = state.symbols.create(name);
         if (seen.insert(sym).second) {
-            auto j2 = getAttr(state, state.sValue, v2->attrs(), "in a {name=...; value=...;} pair");
+            auto j2 = state.getAttr(state.sValue, v2->attrs(), "in a {name=...; value=...;} pair");
             attrs.insert(sym, j2->value, j2->pos);
         }
     }
@@ -4224,7 +4209,7 @@ static void prim_convertHash(EvalState & state, const PosIdx pos, Value * * args
     state.forceAttrs(*args[0], pos, "while evaluating the first argument passed to builtins.convertHash");
     auto inputAttrs = args[0]->attrs();
 
-    auto iteratorHash = getAttr(state, state.symbols.create("hash"), inputAttrs, "while locating the attribute 'hash'");
+    auto iteratorHash = state.getAttr(state.symbols.create("hash"), inputAttrs, "while locating the attribute 'hash'");
     auto hash = state.forceStringNoCtx(*iteratorHash->value, pos, "while evaluating the attribute 'hash'");
 
     auto iteratorHashAlgo = inputAttrs->get(state.symbols.create("hashAlgo"));
@@ -4232,7 +4217,7 @@ static void prim_convertHash(EvalState & state, const PosIdx pos, Value * * args
     if (iteratorHashAlgo)
         ha = parseHashAlgo(state.forceStringNoCtx(*iteratorHashAlgo->value, pos, "while evaluating the attribute 'hashAlgo'"));
 
-    auto iteratorToHashFormat = getAttr(state, state.symbols.create("toHashFormat"), args[0]->attrs(), "while locating the attribute 'toHashFormat'");
+    auto iteratorToHashFormat = state.getAttr(state.symbols.create("toHashFormat"), args[0]->attrs(), "while locating the attribute 'toHashFormat'");
     HashFormat hf = parseHashFormat(state.forceStringNoCtx(*iteratorToHashFormat->value, pos, "while evaluating the attribute 'toHashFormat'"));
 
     v.mkString(Hash::parseAny(hash, ha).to_string(hf, hf == HashFormat::SRI));