"git tree" repositories: honor "inherit env"

In the specification of the action generating a fixed git tree,
also honor "inherit env", i.e., inherit the environment variables
specified in this field from the environment just-mr is invoked in.
As the expected output is fixed ahead of time anyway, this lack of
isolation does not affect correctness.

3 files changed, 32 insertions, 5 deletions

diff --git a/src/other_tools/repo_map/repos_to_setup_map.cpp b/src/other_tools/repo_map/repos_to_setup_map.cpp
index a72903d1..a65a6c50 100644
--- a/src/other_tools/repo_map/repos_to_setup_map.cpp
+++ b/src/other_tools/repo_map/repos_to_setup_map.cpp
@@ -611,6 +611,24 @@ void GitTreeCheckout(ExpressionPtr const& repo_desc,
             }
         }
     }
+    std::vector<std::string> inherit_env{};
+    auto repo_desc_inherit_env =
+        repo_desc->Get("inherit env", Expression::none_t{});
+    if (repo_desc_inherit_env.IsNotNull() and repo_desc_inherit_env->IsList()) {
+        for (auto const& envvar : repo_desc_inherit_env->List()) {
+            if (envvar->IsString()) {
+                inherit_env.emplace_back(envvar->String());
+            }
+            else {
+                (*logger)(
+                    fmt::format("GitTreeCheckout: Not a variable name in the "
+                                "specification of \"inherit env\": {}",
+                                envvar->ToString()),
+                    /*fatal=*/true);
+                return;
+            }
+        }
+    }
     // check "special" pragma
     auto repo_desc_pragma = repo_desc->At("pragma");
     auto pragma_special = repo_desc_pragma
@@ -632,6 +650,7 @@ void GitTreeCheckout(ExpressionPtr const& repo_desc,
     TreeIdInfo tree_id_info = {
         .hash = repo_desc_hash->get()->String(),
         .env_vars = std::move(env),
+        .inherit_env = std::move(inherit_env),
         .command = std::move(cmd),
         .ignore_special = pragma_special_value == PragmaSpecial::Ignore,
         .absent = not fetch_absent and pragma_absent_value};
diff --git a/src/other_tools/root_maps/tree_id_git_map.cpp b/src/other_tools/root_maps/tree_id_git_map.cpp
index a8db186a..ce2fe5e5 100644
--- a/src/other_tools/root_maps/tree_id_git_map.cpp
+++ b/src/other_tools/root_maps/tree_id_git_map.cpp
@@ -14,6 +14,8 @@
 
 #include "src/other_tools/root_maps/tree_id_git_map.hpp"
 
+#include <cstdlib>
+
 #include "fmt/core.h"
 #include "src/buildtool/execution_api/common/execution_common.hpp"
 #include "src/buildtool/file_system/file_root.hpp"
@@ -167,11 +169,15 @@ auto CreateTreeIdGitMap(
                     std::copy(key.command.begin(),
                               key.command.end(),
                               std::back_inserter(cmdline));
-                    auto const command_output =
-                        system.Execute(cmdline,
-                                       key.env_vars,
-                                       tmp_dir->GetPath(),
-                                       out_dir->GetPath());
+                    std::map<std::string, std::string> env{key.env_vars};
+                    for (auto const& k : key.inherit_env) {
+                        const char* v = std::getenv(k.c_str());
+                        if (v != nullptr) {
+                            env[k] = std::string(v);
+                        }
+                    }
+                    auto const command_output = system.Execute(
+                        cmdline, env, tmp_dir->GetPath(), out_dir->GetPath());
                     if (not command_output) {
                         (*logger)(fmt::format("Failed to execute command:\n{}",
                                               nlohmann::json(cmdline).dump()),
diff --git a/src/other_tools/root_maps/tree_id_git_map.hpp b/src/other_tools/root_maps/tree_id_git_map.hpp
index 3c029117..8041919d 100644
--- a/src/other_tools/root_maps/tree_id_git_map.hpp
+++ b/src/other_tools/root_maps/tree_id_git_map.hpp
@@ -17,6 +17,7 @@
 
 #include <string>
 #include <utility>
+#include <vector>
 
 #include "nlohmann/json.hpp"
 #include "src/other_tools/ops_maps/critical_git_op_map.hpp"
@@ -25,6 +26,7 @@
 struct TreeIdInfo {
     std::string hash{}; /* key */
     std::map<std::string, std::string> env_vars{};
+    std::vector<std::string> inherit_env{};
     std::vector<std::string> command{};
     // name of repository for which work is done; used in progress reporting
     std::string origin{};