3 files changed, 13 insertions, 10 deletions

diff --git a/src/libfetchers/fetch-settings.hh b/src/libfetchers/fetch-settings.hh
index 04c9feda0..6452143a1 100644
--- a/src/libfetchers/fetch-settings.hh
+++ b/src/libfetchers/fetch-settings.hh
@@ -70,7 +70,7 @@ struct FetchSettings : public Config
     Setting<bool> warnDirty{this, true, "warn-dirty",
         "Whether to warn about dirty Git/Mercurial trees."};
 
-    Setting<std::string> flakeRegistry{this, "https://github.com/NixOS/flake-registry/raw/master/flake-registry.json", "flake-registry",
+    Setting<std::string> flakeRegistry{this, "https://channels.nixos.org/flake-registry.json", "flake-registry",
         "Path or URI of the global flake registry."};
 
     Setting<bool> useRegistries{this, true, "use-registries",
diff --git a/src/libfetchers/git.cc b/src/libfetchers/git.cc
index 9cbd39247..7d01aaa7a 100644
--- a/src/libfetchers/git.cc
+++ b/src/libfetchers/git.cc
@@ -85,8 +85,9 @@ std::optional<std::string> readHead(const Path & path)
 bool storeCachedHead(const std::string& actualUrl, const std::string& headRef)
 {
     Path cacheDir = getCachePath(actualUrl);
+    auto gitDir = ".";
     try {
-        runProgram("git", true, { "-C", cacheDir, "symbolic-ref", "--", "HEAD", headRef });
+        runProgram("git", true, { "-C", cacheDir, "--git-dir", gitDir, "symbolic-ref", "--", "HEAD", headRef });
     } catch (ExecError &e) {
         if (!WIFEXITED(e.status)) throw;
         return false;
@@ -182,7 +183,7 @@ WorkdirInfo getWorkdirInfo(const Input & input, const Path & workdir)
         if (hasHead) {
             // Using git diff is preferrable over lower-level operations here,
             // because its conceptually simpler and we only need the exit code anyways.
-            auto gitDiffOpts = Strings({ "-C", workdir, "diff", "HEAD", "--quiet"});
+            auto gitDiffOpts = Strings({ "-C", workdir, "--git-dir", gitDir, "diff", "HEAD", "--quiet"});
             if (!submodules) {
                 // Changes in submodules should only make the tree dirty
                 // when those submodules will be copied as well.
@@ -203,6 +204,7 @@ WorkdirInfo getWorkdirInfo(const Input & input, const Path & workdir)
 std::pair<StorePath, Input> fetchFromWorkdir(ref<Store> store, Input & input, const Path & workdir, const WorkdirInfo & workdirInfo)
 {
     const bool submodules = maybeGetBoolAttr(input.attrs, "submodules").value_or(false);
+    auto gitDir = ".git";
 
     if (!fetchSettings.allowDirty)
         throw Error("Git tree '%s' is dirty", workdir);
@@ -210,7 +212,7 @@ std::pair<StorePath, Input> fetchFromWorkdir(ref<Store> store, Input & input, co
     if (fetchSettings.warnDirty)
         warn("Git tree '%s' is dirty", workdir);
 
-    auto gitOpts = Strings({ "-C", workdir, "ls-files", "-z" });
+    auto gitOpts = Strings({ "-C", workdir, "--git-dir", gitDir, "ls-files", "-z" });
     if (submodules)
         gitOpts.emplace_back("--recurse-submodules");
 
@@ -240,7 +242,7 @@ std::pair<StorePath, Input> fetchFromWorkdir(ref<Store> store, Input & input, co
     // modified dirty file?
     input.attrs.insert_or_assign(
         "lastModified",
-        workdirInfo.hasHead ? std::stoull(runProgram("git", true, { "-C", actualPath, "log", "-1", "--format=%ct", "--no-show-signature", "HEAD" })) : 0);
+        workdirInfo.hasHead ? std::stoull(runProgram("git", true, { "-C", actualPath, "--git-dir", gitDir, "log", "-1", "--format=%ct", "--no-show-signature", "HEAD" })) : 0);
 
     return {std::move(storePath), input};
 }
@@ -572,7 +574,7 @@ struct GitInputScheme : InputScheme
         bool isShallow = chomp(runProgram("git", true, { "-C", repoDir, "--git-dir", gitDir, "rev-parse", "--is-shallow-repository" })) == "true";
 
         if (isShallow && !shallow)
-            throw Error("'%s' is a shallow Git repository, but a non-shallow repository is needed", actualUrl);
+            throw Error("'%s' is a shallow Git repository, but shallow repositories are only allowed when `shallow = true;` is specified.", actualUrl);
 
         // FIXME: check whether rev is an ancestor of ref.
 
diff --git a/src/libfetchers/github.cc b/src/libfetchers/github.cc
index 0631fb6e8..a491d82a6 100644
--- a/src/libfetchers/github.cc
+++ b/src/libfetchers/github.cc
@@ -381,7 +381,7 @@ struct SourceHutInputScheme : GitArchiveInputScheme
 
         Headers headers = makeHeadersWithAuthTokens(host);
 
-        std::string ref_uri;
+        std::string refUri;
         if (ref == "HEAD") {
             auto file = store->toRealPath(
                 downloadFile(store, fmt("%s/HEAD", base_url), "source", false, headers).storePath);
@@ -393,10 +393,11 @@ struct SourceHutInputScheme : GitArchiveInputScheme
             if (!remoteLine) {
                 throw BadURL("in '%d', couldn't resolve HEAD ref '%d'", input.to_string(), ref);
             }
-            ref_uri = remoteLine->target;
+            refUri = remoteLine->target;
         } else {
-            ref_uri = fmt("refs/(heads|tags)/%s", ref);
+            refUri = fmt("refs/(heads|tags)/%s", ref);
         }
+        std::regex refRegex(refUri);
 
         auto file = store->toRealPath(
             downloadFile(store, fmt("%s/info/refs", base_url), "source", false, headers).storePath);
@@ -406,7 +407,7 @@ struct SourceHutInputScheme : GitArchiveInputScheme
         std::optional<std::string> id;
         while(!id && getline(is, line)) {
             auto parsedLine = git::parseLsRemoteLine(line);
-            if (parsedLine && parsedLine->reference == ref_uri)
+            if (parsedLine && parsedLine->reference && std::regex_match(*parsedLine->reference, refRegex))
                 id = parsedLine->target;
         }