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NixOS · Dec 3, 2020 · 5d50971 · 5d50971
1 parent 53124da
commit 5d50971
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Showing 4 changed files with 54 additions and 14 deletions.
diff --git a/src/libexpr/eval-inline.hh b/src/libexpr/eval-inline.hh
@@ -37,8 +37,8 @@ void EvalState::forceValue(Value & v, const Pos & pos)
         v.lazyBinOp->expr->evalLazyBinOp(*this, *v.lazyBinOp->env, v);
     } else if (v.type == tValue) {
         v.type = tBlackhole;
-        forceValue(*v.value, pos);
-        v = *v.value;
+        forceValue(*v.value.value, pos != noPos ? pos : *v.value.pos);
+        v = *v.value.value;
     }
 }
 
@@ -84,8 +84,11 @@ Attr * EvalState::evalValueAttr(Value & v, const Symbol & name, const Pos & pos)
     } else if (v.type == tLazyBinOp) {
         return v.lazyBinOp->expr->evalLazyBinOpAttr(*this, *v.lazyBinOp->env, name, v);
     } else if (v.type == tValue) {
-        return evalValueAttr(*v.value, name, pos);
-        // TODO: Set v to v.value if it's in WHNF, for efficiency
+        Attr * result = evalValueAttr(*v.value.value, name, pos != noPos ? pos : *v.value.pos);
+        if (v.value.value->type != tLazyBinOp) {
+            v = *v.value.value;
+        }
+        return result;
     } else {
         return nullptr;
     }

diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
@@ -960,7 +960,12 @@ void Expr::evalMinimal(EvalState & state, Env & env, Value & v)
 void Expr::eval(EvalState & state, Env & env, Value & v)
 {
     evalMinimal(state, env, v);
-    state.forceValue(v, noPos);
+    state.forceValue(v, getPos());
+}
+
+Pos Expr::getPos()
+{
+    return noPos;
 }
 
 
@@ -1107,8 +1112,9 @@ void ExprList::evalMinimal(EvalState & state, Env & env, Value & v)
 void ExprVar::evalMinimal(EvalState & state, Env & env, Value & v)
 {
     v.type = tValue;
-    v.value = state.lookupVar(&env, *this, false);
-    state.evalValueMinimal(*v.value, pos);
+    v.value.value = state.lookupVar(&env, *this, false);
+    v.value.pos = &pos;
+    state.evalValueMinimal(*v.value.value, pos);
 }
 
 static string showAttrPath(EvalState & state, Env & env, const AttrPath & attrPath)
@@ -1170,8 +1176,9 @@ void ExprSelect::evalMinimal(EvalState & state, Env & env, Value & v)
     }
 
     v.type = tValue;
-    v.value = vAttrs;
-    state.evalValueMinimal(*vAttrs, ( pos2 != NULL ? *pos2 : this->pos ));
+    v.value.value = vAttrs;
+    v.value.pos = pos2 != NULL ? pos2 : &pos;
+    state.evalValueMinimal(*vAttrs, *v.value.pos);
 }
 
 
@@ -1517,15 +1524,23 @@ void ExprOpUpdate::evalMinimal(EvalState & state, Env & env, Value & v)
 void ExprOpUpdate::evalLazyBinOp(EvalState & state, Env & env, Value & v)
 {
     if (v.lazyBinOp->rightBlackhole) {
-        throwEvalError(pos, "infinite recursion encountered while recursing into the right side of a lazy binop (evalLazyBinOp)");
+        Pos pos2 = e2->getPos();
+        if (pos2 == noPos) {
+            pos2 = pos;
+        }
+        throwEvalError(pos2, "infinite recursion encountered while recursing into the right side of a lazy binop (evalLazyBinOp)");
     }
     v.lazyBinOp->rightBlackhole = true;
     state.forceAttrs(*v.lazyBinOp->right);
     v.lazyBinOp->rightBlackhole = false;
 
 
     if (v.lazyBinOp->leftBlackhole) {
-        throwEvalError(pos, "infinite recursion encountered while recursing into the left side of a lazy binop (evalLazyBinOp)");
+        Pos pos2 = e1->getPos();
+        if (pos2 == noPos) {
+            pos2 = pos;
+        }
+        throwEvalError(pos2, "infinite recursion encountered while recursing into the left side of a lazy binop (evalLazyBinOp)");
     }
     v.lazyBinOp->leftBlackhole = true;
     state.forceAttrs(*v.lazyBinOp->left);
@@ -1545,7 +1560,11 @@ Attr * ExprOpUpdate::evalLazyBinOpAttr(EvalState & state, Env & env, const Symbo
      */
 
     if (v.lazyBinOp->rightBlackhole) {
-        throwEvalError(pos, "infinite recursion encountered while recursing into the right side of a lazy binop");
+        Pos pos2 = e2->getPos();
+        if (pos2 == noPos) {
+            pos2 = pos;
+        }
+        throwEvalError(pos2, "infinite recursion encountered while recursing into the right side of a lazy binop");
     }
     v.lazyBinOp->rightBlackhole = true;
     Attr * onRight = state.evalValueAttr(*v.lazyBinOp->right, name, pos);
@@ -1555,7 +1574,11 @@ Attr * ExprOpUpdate::evalLazyBinOpAttr(EvalState & state, Env & env, const Symbo
     };
 
     if (v.lazyBinOp->leftBlackhole) {
-        throwEvalError(pos, "infinite recursion encountered while recursing into the left side of a lazy binop");
+        Pos pos2 = e1->getPos();
+        if (pos2 == noPos) {
+            pos2 = pos;
+        }
+        throwEvalError(pos2, "infinite recursion encountered while recursing into the left side of a lazy binop");
     }
     v.lazyBinOp->leftBlackhole = true;
     Attr * onLeft = state.evalValueAttr(*v.lazyBinOp->left, name, pos);

diff --git a/src/libexpr/nixexpr.hh b/src/libexpr/nixexpr.hh
@@ -78,6 +78,7 @@ string showAttrPath(const AttrPath & attrPath);
 struct Expr
 {
     virtual ~Expr() { };
+    virtual Pos getPos();
     virtual void show(std::ostream & str) const;
     virtual void bindVars(const StaticEnv & env);
     virtual void evalMinimal(EvalState & state, Env & env, Value & v);
@@ -178,6 +179,7 @@ struct ExprVar : Expr
     ExprVar(const Symbol & name) : name(name) { };
     ExprVar(const Pos & pos, const Symbol & name) : pos(pos), name(name) { };
     COMMON_METHODS
+    Pos getPos() { return pos; }
     Value * noAllocationValue(EvalState & state, Env & env);
 };
 
@@ -188,6 +190,7 @@ struct ExprSelect : Expr
     AttrPath attrPath;
     ExprSelect(const Pos & pos, Expr * e, const AttrPath & attrPath, Expr * def) : pos(pos), e(e), def(def), attrPath(attrPath) { };
     ExprSelect(const Pos & pos, Expr * e, const Symbol & name) : pos(pos), e(e), def(0) { attrPath.push_back(AttrName(name)); };
+    Pos getPos() { return pos; }
     COMMON_METHODS
 };
 
@@ -267,6 +270,7 @@ struct ExprLambda : Expr
     };
     void setName(Symbol & name);
     string showNamePos() const;
+    Pos getPos() { return pos; }
     COMMON_METHODS
 };
 
@@ -284,6 +288,7 @@ struct ExprWith : Expr
     Expr * attrs, * body;
     size_t prevWith;
     ExprWith(const Pos & pos, Expr * attrs, Expr * body) : pos(pos), attrs(attrs), body(body) { };
+    Pos getPos() { return pos; }
     COMMON_METHODS
 };
 
@@ -292,6 +297,7 @@ struct ExprIf : Expr
     Pos pos;
     Expr * cond, * then, * else_;
     ExprIf(const Pos & pos, Expr * cond, Expr * then, Expr * else_) : pos(pos), cond(cond), then(then), else_(else_) { };
+    Pos getPos() { return pos; }
     COMMON_METHODS
 };
 
@@ -300,6 +306,7 @@ struct ExprAssert : Expr
     Pos pos;
     Expr * cond, * body;
     ExprAssert(const Pos & pos, Expr * cond, Expr * body) : pos(pos), cond(cond), body(body) { };
+    Pos getPos() { return pos; }
     COMMON_METHODS
 };
 
@@ -326,6 +333,7 @@ struct ExprOpNot : Expr
             e1->bindVars(env); e2->bindVars(env); \
         } \
         void evalMinimal(EvalState & state, Env & env, Value & v); \
+        Pos getPos() { return pos; } \
     };
 
 MakeBinOp(ExprApp, "")
@@ -360,6 +368,7 @@ struct ExprOpUpdate : ExprLazyBinOp
     Attr * evalLazyBinOpAttr(EvalState & state, Env & env, const Symbol & name, Value & v);
 
     void updateAttrs(EvalState & state, const Value & v1, const Value & v2, Value & v);
+    Pos getPos() { return pos; }
 };
 
 struct ExprConcatStrings : Expr
@@ -369,13 +378,15 @@ struct ExprConcatStrings : Expr
     vector<Expr *> * es;
     ExprConcatStrings(const Pos & pos, bool forceString, vector<Expr *> * es)
         : pos(pos), forceString(forceString), es(es) { };
+    Pos getPos() { return pos; }
     COMMON_METHODS
 };
 
 struct ExprPos : Expr
 {
     Pos pos;
     ExprPos(const Pos & pos) : pos(pos) { };
+    Pos getPos() { return pos; }
     COMMON_METHODS
 };
 

diff --git a/src/libexpr/value.hh b/src/libexpr/value.hh
@@ -160,7 +160,10 @@ struct Value
         } primOpApp;
         ExternalValueBase * external;
         NixFloat fpoint;
-        Value * value;
+        struct {
+            Value * value;
+            const Pos * pos;
+        } value;
     };
 
     bool isList() const