diff options
| -rw-r--r-- | src/libexpr/primops.cc | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc index c5560be97..3a291e007 100644 --- a/src/libexpr/primops.cc +++ b/src/libexpr/primops.cc @@ -229,10 +229,16 @@ static Expr primDerivationStrict(EvalState & state, const ATermVector & args) ATermMap attrs; queryAllAttrs(evalExpr(state, args[0]), attrs, true); + /* Figure out the name already (for stack backtraces). */ + Expr eDrvName = attrs.get("name"); + if (!eDrvName) + throw Error("required attribute `name' missing"); + ATerm posDrvName; + if (!matchAttrRHS(eDrvName, eDrvName, posDrvName)) abort(); + string drvName = evalString(state, eDrvName); + /* Build the derivation expression by processing the attributes. */ Derivation drv; - - string drvName; string outputHash; string outputHashAlgo; @@ -252,6 +258,8 @@ static Expr primDerivationStrict(EvalState & state, const ATermVector & args) } catch (Error & e) { e.addPrefix(format("while processing the derivation attribute `%1%' at %2%:\n") % key % showPos(pos)); + e.addPrefix(format("while instantiating the derivation named `%1%' at %2%:\n") + % drvName % showPos(posDrvName)); throw; } @@ -285,8 +293,6 @@ static Expr primDerivationStrict(EvalState & state, const ATermVector & args) throw Error("required attribute `builder' missing"); if (drv.platform == "") throw Error("required attribute `system' missing"); - if (drvName == "") - throw Error("required attribute `name' missing"); /* If an output hash was given, check it. */ if (outputHash == "") |