populate: draw inputs from sources that aren't flakes

Generated flakes declared every source they draw inputs from as a flake,
so drawing an input declared with flake = false from a source without
flake.nix failed, although the README says it works.  Such sources get
declared with flake = false now.

An edge case draws a non-flake input from a source without flake.nix.

1 files changed, 11 insertions, 0 deletions

diff --git a/tests/scenarios.nix b/tests/scenarios.nix
index 5dd44db..eeeb665 100644
--- a/tests/scenarios.nix
+++ b/tests/scenarios.nix
@@ -883,6 +883,17 @@ assert !(krops.isLocalTarget (targets.remote "/"));
         '';
       };
     })
+    (s "nonflake-input" {
+      phases = twice {
+        sources = {
+          x.file = { path = "/fixtures/usedata"; inputs.data.follows = "data"; };
+          data.file = "/fixtures/data";
+        };
+        check = ''
+          expect_eq msg "$(nix_eval "$T"/.populate/flakes/x#msg)" data:hello
+        '';
+      };
+    })
   ] ++ lib.optional (targetKind == "local")
     # The target has the path the input is locked to.
     (s "uselocal" {