Add support for bare git repositories with git+file

Local git repositories are normally used directly instead of
cloning. This commit checks if a repo is bare and forces a
clone.

Co-authored-by: Théophane Hufschmitt <regnat@users.noreply.github.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/src/libfetchers/git.cc b/src/libfetchers/git.cc
index 81c647f89..4f9db1bcd 100644
--- a/src/libfetchers/git.cc
+++ b/src/libfetchers/git.cc
@@ -153,12 +153,14 @@ struct GitInputScheme : InputScheme
 
     std::pair<bool, std::string> getActualUrl(const Input & input) const
     {
-        // Don't clone file:// URIs (but otherwise treat them the
-        // same as remote URIs, i.e. don't use the working tree or
-        // HEAD).
+        // file:// URIs are normally not cloned (but otherwise treated the
+        // same as remote URIs, i.e. we don't use the working tree or
+        // HEAD). Exception: If _NIX_FORCE_HTTP is set, or the repo is a bare git
+        // repo, treat as a remote URI to force a clone.
         static bool forceHttp = getEnv("_NIX_FORCE_HTTP") == "1"; // for testing
         auto url = parseURL(getStrAttr(input.attrs, "url"));
-        bool isLocal = url.scheme == "file" && !forceHttp;
+        bool isBareRepository = url.scheme == "file" && !pathExists(url.path + "/.git");
+        bool isLocal = url.scheme == "file" && !forceHttp && !isBareRepository;
         return {isLocal, isLocal ? url.path : url.base};
     }