GitRepo: Remove refspec argument in retrieving commit from remote...

...and use instead the branch name. A valid direct refspec (as those
retrieved by a remote_ls call) will always end in the branch name,
so checking the last path component ('/'-delimited substring) of a
retrieved refspec is enough.

3 files changed, 17 insertions, 19 deletions

diff --git a/src/buildtool/file_system/git_repo.cpp b/src/buildtool/file_system/git_repo.cpp
index 3ad5ba0c..f05be1c2 100644
--- a/src/buildtool/file_system/git_repo.cpp
+++ b/src/buildtool/file_system/git_repo.cpp
@@ -758,7 +758,7 @@ auto GitRepo::GetBranchLocalRefname(std::string const& branch,
 }
 
 auto GitRepo::GetCommitFromRemote(std::string const& repo_url,
-                                  std::string const& branch_refname_local,
+                                  std::string const& branch,
                                   anon_logger_ptr const& logger) noexcept
     -> std::optional<std::string> {
 #ifdef BOOTSTRAP_BUILD_TOOL
@@ -825,21 +825,22 @@ auto GitRepo::GetCommitFromRemote(std::string const& repo_url,
         }
         // figure out what remote branch the local one is tracking
         for (size_t i = 0; i < refs_len; ++i) {
+            // by treating each read reference string as a path we can easily
+            // check for the branch name
             // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-pointer-arithmetic)
-            std::string ref_name{refs[i]->name};
-            if (ref_name == branch_refname_local) {
+            std::filesystem::path ref_name_as_path{refs[i]->name};
+            if (ref_name_as_path.filename() == branch) {
                 // branch found!
                 // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-pointer-arithmetic)
                 std::string new_commit_hash{git_oid_tostr_s(&refs[i]->oid)};
                 return new_commit_hash;
             }
         }
-        (*logger)(
-            fmt::format("could not find branch with refname {} for remote {}",
-                        branch_refname_local,
-                        repo_url,
-                        GitLastError()),
-            true /*fatal*/);
+        (*logger)(fmt::format("could not find branch {} for remote {}",
+                              branch,
+                              repo_url,
+                              GitLastError()),
+                  true /*fatal*/);
         return std::nullopt;
     } catch (std::exception const& ex) {
         Logger::Log(LogLevel::Error,
@@ -1180,7 +1181,7 @@ auto GitRepo::CheckCommitExists(std::string const& commit,
 
 auto GitRepo::UpdateCommitViaTmpRepo(std::filesystem::path const& tmp_repo_path,
                                      std::string const& repo_url,
-                                     std::string const& branch_refname,
+                                     std::string const& branch,
                                      anon_logger_ptr const& logger)
     const noexcept -> std::optional<std::string> {
 #ifdef BOOTSTRAP_BUILD_TOOL
@@ -1205,8 +1206,7 @@ auto GitRepo::UpdateCommitViaTmpRepo(std::filesystem::path const& tmp_repo_path,
                                 msg),
                     fatal);
             });
-        return tmp_repo->GetCommitFromRemote(
-            repo_url, branch_refname, wrapped_logger);
+        return tmp_repo->GetCommitFromRemote(repo_url, branch, wrapped_logger);
     } catch (std::exception const& ex) {
         Logger::Log(LogLevel::Error,
                     "update commit via tmp repo failed with:\n{}",
diff --git a/src/buildtool/file_system/git_repo.hpp b/src/buildtool/file_system/git_repo.hpp
index 3fda0516..3e3bf178 100644
--- a/src/buildtool/file_system/git_repo.hpp
+++ b/src/buildtool/file_system/git_repo.hpp
@@ -146,13 +146,13 @@ class GitRepo {
         std::string const& branch,
         anon_logger_ptr const& logger) noexcept -> std::optional<std::string>;
 
-    /// \brief Retrieve commit hash from remote branch given its refname.
+    /// \brief Retrieve commit hash from remote branch given its name.
     /// Only possible with real repository and thus non-thread-safe.
     /// Returns the retrieved commit hash, or nullopt if failure.
     /// It guarantees the logger is called exactly once with fatal if failure.
     [[nodiscard]] auto GetCommitFromRemote(
         std::string const& repo_url,
-        std::string const& branch_refname_local,
+        std::string const& branch,
         anon_logger_ptr const& logger) noexcept -> std::optional<std::string>;
 
     /// \brief Fetch from given remote. It can either fetch a given named
@@ -206,7 +206,7 @@ class GitRepo {
     /// \brief Get commit from remote via a temporary repository.
     /// Calling it from a fake repository allows thread-safe use.
     /// Creates a temporary real repository at the given location and uses it to
-    /// retrieve from the remote the commit of a branch given its refname.
+    /// retrieve from the remote the commit of a branch given its name.
     /// Caller needs to make sure the temporary directory exists and that the
     /// given path is thread- and process-safe!
     /// Returns the commit hash, as a string, or nullopt if failure.
@@ -214,7 +214,7 @@ class GitRepo {
     [[nodiscard]] auto UpdateCommitViaTmpRepo(
         std::filesystem::path const& tmp_repo_path,
         std::string const& repo_url,
-        std::string const& branch_refname,
+        std::string const& branch,
         anon_logger_ptr const& logger) const noexcept
         -> std::optional<std::string>;
 
diff --git a/src/other_tools/ops_maps/git_update_map.cpp b/src/other_tools/ops_maps/git_update_map.cpp
index 73eccfe0..f2f6c3e5 100644
--- a/src/other_tools/ops_maps/git_update_map.cpp
+++ b/src/other_tools/ops_maps/git_update_map.cpp
@@ -51,10 +51,8 @@ auto CreateGitUpdateMap(GitCASPtr const& git_cas, std::size_t jobs)
                     fatal);
             });
         // update commit
-        auto refname = std::string("refs/heads/") +
-                       key.second;  // assume branch ref format
         auto new_commit = git_repo->UpdateCommitViaTmpRepo(
-            tmp_dir->GetPath(), key.first, refname, wrapped_logger);
+            tmp_dir->GetPath(), key.first, key.second, wrapped_logger);
         if (not new_commit) {
             return;
         }