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, 6 insertions, 4 deletions

diff --git a/src/nix-instantiate/nix-instantiate.cc b/src/nix-instantiate/nix-instantiate.cc
index 6b5ba595d..2b381288a 100644
--- a/src/nix-instantiate/nix-instantiate.cc
+++ b/src/nix-instantiate/nix-instantiate.cc
@@ -168,9 +168,11 @@ static int main_nix_instantiate(int argc, char * * argv)
 
         if (findFile) {
             for (auto & i : files) {
-                Path p = state->findFile(i);
-                if (p == "") throw Error("unable to find '%1%'", i);
-                std::cout << p << std::endl;
+                auto p = state->findFile(i);
+                if (auto fn = p.getPhysicalPath())
+                    std::cout << fn->abs() << std::endl;
+                else
+                    throw Error("'%s' has no physical path", p);
             }
             return 0;
         }
@@ -184,7 +186,7 @@ static int main_nix_instantiate(int argc, char * * argv)
 
         for (auto & i : files) {
             Expr * e = fromArgs
-                ? state->parseExprFromString(i, absPath("."))
+                ? state->parseExprFromString(i, state->rootPath(CanonPath::fromCwd()))
                 : state->parseExprFromFile(resolveExprPath(state->checkSourcePath(lookupFileArg(*state, i))));
             processExpr(*state, attrPaths, parseOnly, strict, autoArgs,
                 evalOnly, outputKind, xmlOutputSourceLocation, e);