just-mr: Fix wrong setup root being picked up

This fixes a bug in which the setup root was falsely being changed
by unconditionally searching early for a default configuration
files, despite one being explicitly provided at the command line.

2 files changed, 10 insertions, 2 deletions

diff --git a/src/buildtool/common/user_structs.hpp b/src/buildtool/common/user_structs.hpp
index 9f67ed45..34101e89 100644
--- a/src/buildtool/common/user_structs.hpp
+++ b/src/buildtool/common/user_structs.hpp
@@ -28,10 +28,13 @@
 
 /* Structures populated exclusively from command line with user-defined data */
 
+static inline const std::filesystem::path kDefaultSetupRoot =
+    FileSystemManager::GetCurrentDirectory();
+
 struct LocalPaths {
     // user-defined locations
     std::optional<std::filesystem::path> root{std::nullopt};
-    std::filesystem::path setup_root{FileSystemManager::GetCurrentDirectory()};
+    std::filesystem::path setup_root = kDefaultSetupRoot;
     std::optional<std::filesystem::path> workspace_root{
         // find workspace root
         []() -> std::optional<std::filesystem::path> {
@@ -45,7 +48,7 @@ struct LocalPaths {
                         });
                 };
             // default path to current dir
-            auto path = FileSystemManager::GetCurrentDirectory();
+            auto path = kDefaultSetupRoot;
             auto root_path = path.root_path();
             while (true) {
                 if (is_workspace_root(path)) {
diff --git a/src/other_tools/just_mr/main.cpp b/src/other_tools/just_mr/main.cpp
index f1836d23..aa1abc74 100644
--- a/src/other_tools/just_mr/main.cpp
+++ b/src/other_tools/just_mr/main.cpp
@@ -265,12 +265,17 @@ auto main(int argc, char* argv[]) -> int {
         }
 
         SetupLogging(arguments.log);
+        // Parse rc file, if given, and returns any configuration file found in
+        // known locations, with the setup root updated accordingly
         auto config_file = ReadJustMRRC(&arguments);
         // As the rc file can contain logging parameters, reset the logging
         // configuration
         SetupLogging(arguments.log);
+        // An explicitly given configuration file path wins. In this case, the
+        // default setup root must be used
         if (arguments.common.repository_config) {
             config_file = arguments.common.repository_config;
+            arguments.common.just_mr_paths->setup_root = kDefaultSetupRoot;
         }
 
         // if optional args were not read from just-mrrc or given by user, use