Backport SourcePath from the lazy-trees branch

This introduces the SourcePath type from lazy-trees as an abstraction
for accessing files from inputs that may not be materialized in the
real filesystem (e.g. Git repositories). Currently, however, it's just
a wrapper around CanonPath, so it shouldn't change any behaviour. (On
lazy-trees, SourcePath is a <InputAccessor, CanonPath> tuple.)

1 files changed, 2 insertions, 1 deletions

diff --git a/src/libcmd/common-eval-args.hh b/src/libcmd/common-eval-args.hh
index b69db11dd..83edcfb85 100644
--- a/src/libcmd/common-eval-args.hh
+++ b/src/libcmd/common-eval-args.hh
@@ -8,6 +8,7 @@ namespace nix {
 class Store;
 class EvalState;
 class Bindings;
+struct SourcePath;
 
 struct MixEvalArgs : virtual Args
 {
@@ -25,6 +26,6 @@ private:
     std::map<std::string, std::string> autoArgs;
 };
 
-Path lookupFileArg(EvalState & state, std::string_view s);
+SourcePath lookupFileArg(EvalState & state, std::string_view s);
 
 }