git repo fetch: support "inherit env"

When fetching git repositories, just-mr routinely shells out to
git. In this case, allow the user to specify via "inherit env",
which environment variables from the host environment should be
made available in this action. Typical variables to inherit are
ones providing credentials, like SSH_AUTH_SOCK. As the repository
description specifies the commit that will be taken, and hence the
resulting tree, correctness is not affected by the environement
leaking in here.

1 files changed, 19 insertions, 5 deletions

diff --git a/src/other_tools/git_operations/git_repo_remote.cpp b/src/other_tools/git_operations/git_repo_remote.cpp
index cb2ff7a0..ac4bc41c 100644
--- a/src/other_tools/git_operations/git_repo_remote.cpp
+++ b/src/other_tools/git_operations/git_repo_remote.cpp
@@ -395,6 +395,7 @@ auto GitRepoRemote::UpdateCommitViaTmpRepo(
     std::filesystem::path const& tmp_dir,
     std::string const& repo_url,
     std::string const& branch,
+    std::vector<std::string> const& inherit_env,
     std::string const& git_bin,
     std::vector<std::string> const& launcher,
     anon_logger_ptr const& logger) const noexcept
@@ -442,11 +443,18 @@ auto GitRepoRemote::UpdateCommitViaTmpRepo(
             "Git commit update for remote {} must shell out. Running:\n{}",
             repo_url,
             nlohmann::json(cmdline).dump());
+        std::map<std::string, std::string> env{};
+        for (auto const& k : inherit_env) {
+            const char* v = std::getenv(k.c_str());
+            if (v != nullptr) {
+                env[k] = std::string(v);
+            }
+        }
         // set up the system command
         SystemCommand system{repo_url};
         auto const command_output =
             system.Execute(cmdline,
-                           {},            // default env
+                           env,
                            GetGitPath(),  // which path is not actually relevant
                            tmp_dir);
         // output file can be read anyway
@@ -510,6 +518,7 @@ auto GitRepoRemote::UpdateCommitViaTmpRepo(
 auto GitRepoRemote::FetchViaTmpRepo(std::filesystem::path const& tmp_dir,
                                     std::string const& repo_url,
                                     std::optional<std::string> const& branch,
+                                    std::vector<std::string> const& inherit_env,
                                     std::string const& git_bin,
                                     std::vector<std::string> const& launcher,
                                     anon_logger_ptr const& logger) noexcept
@@ -580,12 +589,17 @@ auto GitRepoRemote::FetchViaTmpRepo(std::filesystem::path const& tmp_dir,
                     "Git fetch for remote {} must shell out. Running:\n{}",
                     repo_url,
                     nlohmann::json(cmdline).dump());
+        std::map<std::string, std::string> env{};
+        for (auto const& k : inherit_env) {
+            const char* v = std::getenv(k.c_str());
+            if (v != nullptr) {
+                env[k] = std::string(v);
+            }
+        }
         // run command
         SystemCommand system{repo_url};
-        auto const command_output = system.Execute(cmdline,
-                                                   {},  // caller env
-                                                   GetGitPath(),
-                                                   tmp_dir);
+        auto const command_output =
+            system.Execute(cmdline, env, GetGitPath(), tmp_dir);
         if (not command_output) {
             std::string out_str{};
             std::string err_str{};