From 89865144c3ba0162cd37bcbe49b3095e9bab4164 Mon Sep 17 00:00:00 2001 From: Bas van Dijk Date: Tue, 30 Jul 2019 11:22:55 +0200 Subject: [PATCH] Allow builtins.pathExists to check the existence of /nix/store paths This makes it consitent with builtins.readDir. --- src/libexpr/primops.cc | 10 ++++++++-- tests/import-derivation.nix | 5 ++++- 2 files changed, 12 insertions(+), 3 deletions(-) diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc index 070e72f3a..350dba474 100644 --- a/src/libexpr/primops.cc +++ b/src/libexpr/primops.cc @@ -832,8 +832,14 @@ static void prim_pathExists(EvalState & state, const Pos & pos, Value * * args, { PathSet context; Path path = state.coerceToPath(pos, *args[0], context); - if (!context.empty()) - throw EvalError(format("string '%1%' cannot refer to other paths, at %2%") % path % pos); + try { + state.realiseContext(context); + } catch (InvalidPathError & e) { + throw EvalError(format( + "cannot check the existence of '%1%', since path '%2%' is not valid, at %3%") + % path % e.path % pos); + } + try { mkBool(v, pathExists(state.checkSourcePath(path))); } catch (SysError & e) { diff --git a/tests/import-derivation.nix b/tests/import-derivation.nix index 91adcd288..44fa9a45d 100644 --- a/tests/import-derivation.nix +++ b/tests/import-derivation.nix @@ -10,7 +10,10 @@ let ''; }; - value = import bar; + value = + # Test that pathExists can check the existence of /nix/store paths + assert builtins.pathExists bar; + import bar; in