Restore backwards-compat for current `builtins.fetchGit`

If a repo is dirty, it used to return a `rev` object with an "empty"
sha1 (0000000000000000000000000000000000000000). Please note that this
only applies for `builtins.fetchGit` and *not* for `builtins.fetchTree{
type = "git"; }`.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libexpr/flake/flake.hh b/src/libexpr/flake/flake.hh
index 77f3abdeb..c2bb2888b 100644
--- a/src/libexpr/flake/flake.hh
+++ b/src/libexpr/flake/flake.hh
@@ -106,6 +106,6 @@ void emitTreeAttrs(
     EvalState & state,
     const fetchers::Tree & tree,
     const fetchers::Input & input,
-    Value & v);
+    Value & v, bool emptyRevFallback = false);
 
 }