wroclaw-git-backups/nix
1
0
Fork 0
mirror of https://github.com/NixOS/nix synced 2025-06-25 10:41:16 +02:00
Code Activity

evaluate inherit (from) exprs only once per directive

Browse source 
desugaring inherit-from to syntactic duplication of the source expr also
duplicates side effects of the source expr (such as trace calls) and
expensive computations (such as derivationStrict).
This commit is contained in:
pennae 2024-01-27 16:33:34 +01:00
parent ecf8b12d60
commit cefd0302b5
9 changed files with 109 additions and 15 deletions
Download patch file Download diff file Expand all files Collapse all files

7
src/libexpr/parser.y
View file

@ -321,14 +321,17 @@ binds
}
| binds INHERIT '(' expr ')' attrs ';'
{ $$ = $1;
/* !!! Should ensure sharing of the expression in $4. */
if (!$$->inheritFromExprs)
$$->inheritFromExprs = std::make_unique<std::vector<Expr *>>();
$$->inheritFromExprs->push_back($4);
auto from = new nix::ExprInheritFrom(state->at(@4), $$->inheritFromExprs->size() - 1);
for (auto & i : *$6) {
if ($$->attrs.find(i.symbol) != $$->attrs.end())
state->dupAttr(i.symbol, state->at(@6), $$->attrs[i.symbol].pos);
$$->attrs.emplace(
i.symbol,
ExprAttrs::AttrDef(
new ExprSelect(CUR_POS, $4, i.symbol),
new ExprSelect(CUR_POS, from, i.symbol),
state->at(@6),
ExprAttrs::AttrDef::Kind::InheritedFrom));
}