From 9846305fee6992a0fa6da066bf381aee3e703ce5 Mon Sep 17 00:00:00 2001
From: John Ericson <John.Ericson@Obsidian.Systems>
Date: Sun, 9 Nov 2025 18:11:31 -0500
Subject: [PATCH] Switch to libgit2 experimental

Just patch the package for now, but we should make Nixpkgs provide what
we need (whether that the experimental variant, or a 2.x release with
the new API made non-experimental) before releasing this change.
---
 packaging/dependencies.nix                    | 10 +++++
 src/libfetchers-tests/git-utils.cc            | 16 +++----
 src/libfetchers-tests/git.cc                  |  2 +-
 src/libfetchers-tests/meson.build             |  2 +-
 src/libfetchers/git-lfs-fetch.cc              |  8 ++--
 src/libfetchers/git-utils.cc                  | 42 +++++++++----------
 .../include/nix/fetchers/git-lfs-fetch.hh     |  2 +-
 src/libfetchers/meson.build                   |  2 +-
 8 files changed, 47 insertions(+), 37 deletions(-)

diff --git a/packaging/dependencies.nix b/packaging/dependencies.nix
index 6b2dafcfa..517f55de3 100644
--- a/packaging/dependencies.nix
+++ b/packaging/dependencies.nix
@@ -74,4 +74,14 @@ scope: {
         buildPhase = lib.replaceStrings [ "--without-python" ] [ "" ] old.buildPhase;
         installPhase = lib.replaceStrings [ "--without-python" ] [ "" ] old.installPhase;
       });
+
+  libgit2 = pkgs.libgit2.overrideAttrs (attrs: {
+    cmakeFlags = (attrs.cmakeFlags or [ ]) ++ [
+      (lib.mesonBool "EXPERIMENTAL_SHA256" true)
+    ];
+
+    postInstall = (attrs.postInstall or "") + ''
+      substituteInPlace $(find $dev/include -type f) --replace-quiet '#include "git2/' '#include "git2-experimental/'
+    '';
+  });
 }
diff --git a/src/libfetchers-tests/git-utils.cc b/src/libfetchers-tests/git-utils.cc
index 774934d26..f04835264 100644
--- a/src/libfetchers-tests/git-utils.cc
+++ b/src/libfetchers-tests/git-utils.cc
@@ -1,19 +1,19 @@
 #include "nix/fetchers/git-utils.hh"
 #include "nix/util/file-system.hh"
 #include <gmock/gmock.h>
-#include <git2/global.h>
-#include <git2/repository.h>
-#include <git2/signature.h>
-#include <git2/types.h>
-#include <git2/object.h>
-#include <git2/tag.h>
+#include <git2-experimental/global.h>
+#include <git2-experimental/repository.h>
+#include <git2-experimental/signature.h>
+#include <git2-experimental/types.h>
+#include <git2-experimental/object.h>
+#include <git2-experimental/tag.h>
 #include <gtest/gtest.h>
 #include "nix/util/fs-sink.hh"
 #include "nix/util/serialise.hh"
 #include "nix/fetchers/git-lfs-fetch.hh"
 
-#include <git2/blob.h>
-#include <git2/tree.h>
+#include <git2-experimental/blob.h>
+#include <git2-experimental/tree.h>
 
 namespace nix {
 
diff --git a/src/libfetchers-tests/git.cc b/src/libfetchers-tests/git.cc
index 4f0e0d974..3a9306b56 100644
--- a/src/libfetchers-tests/git.cc
+++ b/src/libfetchers-tests/git.cc
@@ -5,7 +5,7 @@
 #include "nix/fetchers/fetchers.hh"
 #include "nix/fetchers/git-utils.hh"
 
-#include <git2.h>
+#include <git2-experimental.h>
 #include <gtest/gtest.h>
 
 #include <filesystem>
diff --git a/src/libfetchers-tests/meson.build b/src/libfetchers-tests/meson.build
index a18f64d79..2f8c54714 100644
--- a/src/libfetchers-tests/meson.build
+++ b/src/libfetchers-tests/meson.build
@@ -33,7 +33,7 @@ deps_private += rapidcheck
 gtest = dependency('gtest', main : true)
 deps_private += gtest
 
-libgit2 = dependency('libgit2')
+libgit2 = dependency('libgit2-experimental')
 deps_private += libgit2
 
 subdir('nix-meson-build-support/common')
diff --git a/src/libfetchers/git-lfs-fetch.cc b/src/libfetchers/git-lfs-fetch.cc
index 936976e55..90f030381 100644
--- a/src/libfetchers/git-lfs-fetch.cc
+++ b/src/libfetchers/git-lfs-fetch.cc
@@ -7,10 +7,10 @@
 #include "nix/util/hash.hh"
 #include "nix/store/ssh.hh"
 
-#include <git2/attr.h>
-#include <git2/config.h>
-#include <git2/errors.h>
-#include <git2/remote.h>
+#include <git2-experimental/attr.h>
+#include <git2-experimental/config.h>
+#include <git2-experimental/errors.h>
+#include <git2-experimental/remote.h>
 
 #include <nlohmann/json.hpp>
 
diff --git a/src/libfetchers/git-utils.cc b/src/libfetchers/git-utils.cc
index 1bd5b0b94..8eca1fe91 100644
--- a/src/libfetchers/git-utils.cc
+++ b/src/libfetchers/git-utils.cc
@@ -13,27 +13,27 @@
 #include "nix/util/thread-pool.hh"
 #include "nix/util/pool.hh"
 
-#include <git2/attr.h>
-#include <git2/blob.h>
-#include <git2/branch.h>
-#include <git2/commit.h>
-#include <git2/config.h>
-#include <git2/describe.h>
-#include <git2/errors.h>
-#include <git2/global.h>
-#include <git2/indexer.h>
-#include <git2/object.h>
-#include <git2/odb.h>
-#include <git2/refs.h>
-#include <git2/remote.h>
-#include <git2/repository.h>
-#include <git2/revparse.h>
-#include <git2/status.h>
-#include <git2/submodule.h>
-#include <git2/sys/odb_backend.h>
-#include <git2/sys/mempack.h>
-#include <git2/tag.h>
-#include <git2/tree.h>
+#include <git2-experimental/attr.h>
+#include <git2-experimental/blob.h>
+#include <git2-experimental/branch.h>
+#include <git2-experimental/commit.h>
+#include <git2-experimental/config.h>
+#include <git2-experimental/describe.h>
+#include <git2-experimental/errors.h>
+#include <git2-experimental/global.h>
+#include <git2-experimental/indexer.h>
+#include <git2-experimental/object.h>
+#include <git2-experimental/odb.h>
+#include <git2-experimental/refs.h>
+#include <git2-experimental/remote.h>
+#include <git2-experimental/repository.h>
+#include <git2-experimental/revparse.h>
+#include <git2-experimental/status.h>
+#include <git2-experimental/submodule.h>
+#include <git2-experimental/sys/odb_backend.h>
+#include <git2-experimental/sys/mempack.h>
+#include <git2-experimental/tag.h>
+#include <git2-experimental/tree.h>
 
 #include <boost/unordered/concurrent_flat_set.hpp>
 #include <boost/unordered/unordered_flat_map.hpp>
diff --git a/src/libfetchers/include/nix/fetchers/git-lfs-fetch.hh b/src/libfetchers/include/nix/fetchers/git-lfs-fetch.hh
index b59da391a..c46278c05 100644
--- a/src/libfetchers/include/nix/fetchers/git-lfs-fetch.hh
+++ b/src/libfetchers/include/nix/fetchers/git-lfs-fetch.hh
@@ -5,7 +5,7 @@
 #include "nix/util/serialise.hh"
 #include "nix/util/url.hh"
 
-#include <git2/repository.h>
+#include <git2-experimental/repository.h>
 
 #include <nlohmann/json_fwd.hpp>
 
diff --git a/src/libfetchers/meson.build b/src/libfetchers/meson.build
index d34dd4f43..d5ad8ecc3 100644
--- a/src/libfetchers/meson.build
+++ b/src/libfetchers/meson.build
@@ -28,7 +28,7 @@ subdir('nix-meson-build-support/subprojects')
 nlohmann_json = dependency('nlohmann_json', version : '>= 3.9')
 deps_public += nlohmann_json
 
-libgit2 = dependency('libgit2', version : '>= 1.9')
+libgit2 = dependency('libgit2-experimental', version : '>= 1.9')
 deps_private += libgit2
 
 subdir('nix-meson-build-support/common')