diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/libexpr/eval.cc | 19 | ||||
| -rw-r--r-- | src/libexpr/eval.hh | 5 | ||||
| -rw-r--r-- | src/libexpr/flake/flake.cc | 7 | ||||
| -rw-r--r-- | src/libexpr/value.hh | 5 |
4 files changed, 28 insertions, 8 deletions
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc index 25b50da7e..ec751ad31 100644 --- a/src/libexpr/eval.cc +++ b/src/libexpr/eval.cc @@ -179,6 +179,18 @@ string showType(const Value & v) } +bool Value::isTrivial() const +{ + return + type != tApp + && type != tPrimOpApp + && (type != tThunk + || (dynamic_cast<ExprAttrs *>(thunk.expr) + && ((ExprAttrs *) thunk.expr)->dynamicAttrs.empty()) + || dynamic_cast<ExprLambda *>(thunk.expr)); +} + + #if HAVE_BOEHMGC /* Called when the Boehm GC runs out of memory. */ static void * oomHandler(size_t requested) @@ -749,7 +761,7 @@ Value * ExprPath::maybeThunk(EvalState & state, Env & env) } -void EvalState::evalFile(const Path & path_, Value & v) +void EvalState::evalFile(const Path & path_, Value & v, bool mustBeTrivial) { auto path = checkSourcePath(path_); @@ -778,6 +790,11 @@ void EvalState::evalFile(const Path & path_, Value & v) fileParseCache[path2] = e; try { + // Enforce that 'flake.nix' is a direct attrset, not a + // computation. + if (mustBeTrivial && + !(dynamic_cast<ExprAttrs *>(e))) + throw Error("file '%s' must be an attribute set", path); eval(e, v); } catch (Error & e) { addErrorPrefix(e, "while evaluating the file '%1%':\n", path2); diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh index 468a826ca..16350a5bf 100644 --- a/src/libexpr/eval.hh +++ b/src/libexpr/eval.hh @@ -157,8 +157,9 @@ public: Expr * parseStdin(); /* Evaluate an expression read from the given file to normal - form. */ - void evalFile(const Path & path, Value & v); + form. Optionally enforce that the top-level expression is + trivial (i.e. doesn't require arbitrary computation). */ + void evalFile(const Path & path, Value & v, bool mustBeTrivial = false); void resetFileCache(); diff --git a/src/libexpr/flake/flake.cc b/src/libexpr/flake/flake.cc index c10906731..050e65259 100644 --- a/src/libexpr/flake/flake.cc +++ b/src/libexpr/flake/flake.cc @@ -198,9 +198,7 @@ static SourceInfo fetchFlake(EvalState & state, const FlakeRef & resolvedRef) static void expectType(EvalState & state, ValueType type, Value & value, const Pos & pos) { - if (value.type == tThunk && - ((type == tAttrs && dynamic_cast<ExprAttrs *>(value.thunk.expr)) || - (type == tLambda && dynamic_cast<ExprLambda *>(value.thunk.expr)))) + if (value.type == tThunk && value.isTrivial()) state.forceValue(value, pos); if (value.type != type) throw Error("expected %s but got %s at %s", @@ -231,8 +229,7 @@ Flake getFlake(EvalState & state, const FlakeRef & flakeRef) throw Error("source tree referenced by '%s' does not contain a '%s/flake.nix' file", resolvedRef, resolvedRef.subdir); Value vInfo; - // FIXME: don't evaluate vInfo. - state.evalFile(realFlakeFile, vInfo); // FIXME: symlink attack + state.evalFile(realFlakeFile, vInfo, true); // FIXME: symlink attack expectType(state, tAttrs, vInfo, Pos(state.symbols.create(realFlakeFile), 0, 0)); diff --git a/src/libexpr/value.hh b/src/libexpr/value.hh index e1ec87d3b..bdf2cdde1 100644 --- a/src/libexpr/value.hh +++ b/src/libexpr/value.hh @@ -170,6 +170,11 @@ struct Value { return type == tList1 ? 1 : type == tList2 ? 2 : bigList.size; } + + /* Check whether forcing this value requires a trivial amount of + computation. In particular, function applications are + non-trivial. */ + bool isTrivial() const; }; |