1 files changed, 47 insertions, 18 deletions

diff --git a/libbuild2/file.cxx b/libbuild2/file.cxx
index 0bcb198..571980e 100644
--- a/libbuild2/file.cxx
+++ b/libbuild2/file.cxx
@@ -17,7 +17,8 @@
 #include <libbuild2/lexer.hxx>
 #include <libbuild2/parser.hxx>
 
-#include <libbuild2/config/utility.hxx> // lookup_config()
+#include <libbuild2/config/module.hxx>  // config::module::version
+#include <libbuild2/config/utility.hxx> // config::lookup_config()
 
 using namespace std;
 using namespace butl;
@@ -310,13 +311,13 @@ namespace build2
   }
 
   scope_map::iterator
-  create_root (scope& s, const dir_path& out_root, const dir_path& src_root)
+  create_root (context& ctx,
+               const dir_path& out_root,
+               const dir_path& src_root)
   {
-    auto i (s.ctx.scopes.rw (s).insert (out_root, true /* root */));
+    auto i (ctx.scopes.rw ().insert (out_root, true /* root */));
     scope& rs (i->second);
 
-    context& ctx (rs.ctx);
-
     // Set out_path. Note that src_path is set in setup_root() below.
     //
     if (rs.out_path_ != &i->first)
@@ -1208,7 +1209,7 @@ namespace build2
     // probably be tried first since that src_root was explicitly configured
     // by the user. After that, #2 followed by #1 seems reasonable.
     //
-    scope& rs (create_root (root, out_root, dir_path ())->second);
+    scope& rs (create_root (ctx, out_root, dir_path ())->second);
 
     bool bstrapped (bootstrapped (rs));
 
@@ -1275,7 +1276,7 @@ namespace build2
 
         // The same logic to src_root as in create_bootstrap_outer().
         //
-        scope& rs (create_root (root, out_root, dir_path ())->second);
+        scope& rs (create_root (ctx, out_root, dir_path ())->second);
 
         optional<bool> altn;
         if (!bootstrapped (rs))
@@ -1466,17 +1467,16 @@ namespace build2
   }
 
   scope&
-  load_project (scope& s,
+  load_project (context& ctx,
                 const dir_path& out_root,
                 const dir_path& src_root,
                 bool forwarded,
                 bool load)
   {
+    assert (ctx.phase == run_phase::load);
     assert (!forwarded || out_root != src_root);
 
-    context& ctx (s.ctx);
-
-    auto i (create_root (s, out_root, src_root));
+    auto i (create_root (ctx, out_root, src_root));
     scope& rs (i->second);
 
     if (!bootstrapped (rs))
@@ -2065,13 +2065,11 @@ namespace build2
       fwd = (src_root != out_root);
     }
 
-    scope& gs (ctx.global_scope.rw ());
-
     for (const scope* proot (nullptr); ; proot = root)
     {
       bool top (proot == nullptr);
 
-      root = &create_root (gs, out_root, src_root)->second;
+      root = &create_root (ctx, out_root, src_root)->second;
 
       bool bstrapped (bootstrapped (*root));
 
@@ -2153,6 +2151,8 @@ namespace build2
     //
     load_root (*root);
 
+    scope& gs (ctx.global_scope.rw ());
+
     // Use a temporary scope so that the export stub doesn't mess anything up.
     //
     temp_scope ts (gs);
@@ -2555,11 +2555,14 @@ namespace build2
                   const string&  rpre,
                   const strings& rmod,
                   const string&  rpos,
-                  const optional<string>& config,
+                  const optional<string>& config_mod,
+                  const optional<string>& config_file,
                   bool buildfile,
                   const char* who,
                   uint16_t verbosity)
   {
+    assert (!config_file || (config_mod && *config_mod == "config"));
+
     string hdr ("# Generated by " + string (who) + ". Edit if you know"
                 " what you are doing.\n"
                 "#");
@@ -2610,12 +2613,12 @@ namespace build2
 
         ofs << endl;
 
-        if (config)
-          ofs << "using " << *config << endl;
+        if (config_mod)
+          ofs << "using " << *config_mod << endl;
 
         for (const string& m: bmod)
         {
-          if (!config || m != *config)
+          if (!config_mod || m != *config_mod)
             ofs << "using " << m << endl;
         }
 
@@ -2675,6 +2678,32 @@ namespace build2
       }
     }
 
+    // Write build/config.build.
+    //
+    if (config_file)
+    {
+      path f (d / std_build_dir / "config.build"); // std_config_file
+
+      if (verb >= verbosity)
+        text << (verb >= 2 ? "cat >" : "save ") << f;
+
+      try
+      {
+        ofdstream ofs (f);
+
+        ofs << hdr << endl
+            << "config.version = " << config::module::version << endl
+            << endl
+            << *config_file << endl;
+
+        ofs.close ();
+      }
+      catch (const io_error& e)
+      {
+        fail << "unable to write to " << f << ": " << e;
+      }
+    }
+
     // Write root buildfile.
     //
     if (buildfile)