diff options
| -rw-r--r-- | src/libexpr/eval.cc | 10 | ||||
| -rw-r--r-- | tests/lang/eval-okay-null-dynamic-attrs.exp | 1 | ||||
| -rw-r--r-- | tests/lang/eval-okay-null-dynamic-attrs.nix | 1 |
3 files changed, 11 insertions, 1 deletions
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc index 350a4fbe1..730b431cf 100644 --- a/src/libexpr/eval.cc +++ b/src/libexpr/eval.cc @@ -642,7 +642,15 @@ void ExprAttrs::eval(EvalState & state, Env & env, Value & v) /* dynamic attrs apply *after* rec and __overrides */ foreach (DynamicAttrDefs::iterator, i, dynamicAttrs) { Value nameVal; - i->nameExpr->eval(state, *dynamicEnv, nameVal); + assert(dynamic_cast<ExprConcatStrings *>(i->nameExpr)); + ExprConcatStrings * nameExpr = static_cast<ExprConcatStrings *>(i->nameExpr); + if (nameExpr->es->size() == 1) { + nameExpr->es->front()->eval(state, *dynamicEnv, nameVal); + state.forceValue(nameVal); + if (nameVal.type == tNull) + continue; + } + nameExpr->eval(state, *dynamicEnv, nameVal); state.forceStringNoCtx(nameVal); Symbol nameSym = state.symbols.create(nameVal.string.s); Bindings::iterator j = v.attrs->find(nameSym); diff --git a/tests/lang/eval-okay-null-dynamic-attrs.exp b/tests/lang/eval-okay-null-dynamic-attrs.exp new file mode 100644 index 000000000..27ba77dda --- /dev/null +++ b/tests/lang/eval-okay-null-dynamic-attrs.exp @@ -0,0 +1 @@ +true diff --git a/tests/lang/eval-okay-null-dynamic-attrs.nix b/tests/lang/eval-okay-null-dynamic-attrs.nix new file mode 100644 index 000000000..b060c0bc9 --- /dev/null +++ b/tests/lang/eval-okay-null-dynamic-attrs.nix @@ -0,0 +1 @@ +{ ${null} = true; } == {} |