Rehash root lookup, if building in compatible mode

To avoid unnecessary staging and git imports of computed roots for
build in compatible mode, use the rehashing functionality to allow
us to compute the git tree of that root in memory.

1 files changed, 10 insertions, 0 deletions

diff --git a/src/buildtool/main/main.cpp b/src/buildtool/main/main.cpp
index b1e3dbad..34125fcd 100644
--- a/src/buildtool/main/main.cpp
+++ b/src/buildtool/main/main.cpp
@@ -1041,9 +1041,19 @@ auto main(int argc, char* argv[]) -> int {
         std::size_t eval_root_jobs =
             std::lround(std::ceil(std::sqrt(arguments.common.jobs)));
 #ifndef BOOTSTRAP_BUILD_TOOL
+        const bool need_rehash =
+            arguments.protocol.hash_type != HashFunction::Type::GitSHA1;
+        const auto git_storage_config =
+            need_rehash ? CreateStorageConfig(arguments.endpoint,
+                                              HashFunction::Type::GitSHA1)
+                        : std::nullopt;
+        if (need_rehash and (not git_storage_config)) {
+            return kExitFailure;
+        }
         if (not EvaluateComputedRoots(&repo_config,
                                       main_repo,
                                       *storage_config,
+                                      git_storage_config,
                                       traverse_args,
                                       &exec_context,
                                       eval_root_jobs)) {