Add support for additional *-build package manifest values and alternative buildfile naming

18 files changed, 523 insertions, 155 deletions

diff --git a/bpkg/manifest-utility.cxx b/bpkg/manifest-utility.cxx
index d205c2d..56da715 100644
--- a/bpkg/manifest-utility.cxx
+++ b/bpkg/manifest-utility.cxx
@@ -3,9 +3,11 @@
 
 #include <bpkg/manifest-utility.hxx>
 
+#include <sstream>
 #include <cstring> // strcspn()
 
 #include <libbutl/b.hxx>
+#include <libbutl/filesystem.hxx>  // dir_iterator
 
 #include <bpkg/package.hxx>        // wildcard_version
 #include <bpkg/diagnostics.hxx>
@@ -357,19 +359,73 @@ namespace bpkg
     }
   }
 
+  // Return the sorted list of *.build files (first) which are present in the
+  // package's build/config/ subdirectory (or their alternatives) together
+  // with the *-build manifest value names they correspond to (second). Skip
+  // files which are already present in the specified list. Note: throws
+  // system_error on filesystem errors.
+  //
+  static vector<pair<path, path>>
+  find_buildfiles (const dir_path& config,
+                   const string& ext,
+                   const vector<buildfile>& bs)
+  {
+    vector<pair<path, path>> r;
+
+    for (const dir_entry& de:
+           dir_iterator (config, false /* ignore_dangling */))
+    {
+      if (de.type () == entry_type::regular)
+      {
+        const path& p (de.path ());
+        const char* e (p.extension_cstring ());
+
+        if (e != nullptr && ext == e)
+        {
+          path f (config.leaf () / p.base ()); // Relative to build/.
+
+          if (find_if (bs.begin (), bs.end (),
+                       [&f] (const auto& v) {return v.path == f;}) ==
+              bs.end ())
+          {
+            r.emplace_back (config / p, move (f));
+          }
+        }
+      }
+    }
+
+    sort (r.begin (), r.end (),
+          [] (const auto& x, const auto& y) {return x.second < y.second;});
+
+    return r;
+  }
+
   string
   package_buildfiles_checksum (const optional<string>& bb,
                                const optional<string>& rb,
-                               const dir_path& d)
+                               const vector<buildfile>& bs,
+                               const dir_path& d,
+                               optional<bool> an)
   {
-    if (bb && rb)
+    if (d.empty ())
     {
+      assert (bb);
+
       sha256 cs (*bb);
-      cs.append (*rb);
+
+      if (rb)
+        cs.append (*rb);
+
+      for (const buildfile& b: bs)
+        cs.append (b.content);
+
       return cs.string ();
     }
 
-    auto checksum = [&bb, &rb] (const path& b, const path& r)
+    auto checksum = [&bb, &rb, &bs] (const path& b,
+                                     const path& r,
+                                     const dir_path& c,
+                                     const string& e)
     {
       sha256 cs;
 
@@ -396,24 +452,176 @@ namespace bpkg
       else
         append_file (b);
 
+      bool root (true);
+
       if (rb)
         cs.append (*rb);
       else if (exists (r))
         append_file (r);
+      else
+        root = false;
+
+      for (const buildfile& b: bs)
+        cs.append (b.content);
+
+      if (root && exists (c))
+      try
+      {
+        for (auto& f: find_buildfiles (c, e, bs))
+          append_file (f.first);
+      }
+      catch (const system_error& e)
+      {
+        fail << "unable to scan directory " << c << ": " << e;
+      }
 
       return string (cs.string ());
     };
 
-    // Check the alternative bootstrap file first since it is more
-    // specific.
+    // Verify that the deduced naming scheme matches the specified one and
+    // fail if that's not the case.
+    //
+    auto verify = [an, &d] (bool alt_naming)
+    {
+      assert (an);
+
+      if (*an != alt_naming)
+        fail << "buildfile naming scheme mismatch between manifest and "
+             << "package directory " << d;
+    };
+
+    // Check the alternative bootstrap file first since it is more specific.
     //
     path bf;
     if (exists (bf = d / alt_bootstrap_file))
-      return checksum (bf, d / alt_root_file);
+    {
+      if (an)
+        verify (true /* alt_naming */);
+
+      return checksum (bf,
+                       d / alt_root_file,
+                       d / alt_config_dir,
+                       alt_build_ext);
+    }
     else if (exists (bf = d / std_bootstrap_file))
-      return checksum (bf, d / std_root_file);
+    {
+      if (an)
+        verify (false /* alt_naming */);
+
+      return checksum (bf,
+                       d / std_root_file,
+                       d / std_config_dir,
+                       std_build_ext);
+    }
     else
       fail << "unable to find bootstrap.build file in package directory "
            << d << endf;
   }
+
+  void
+  load_package_buildfiles (package_manifest& m, const dir_path& d, bool erp)
+  {
+    auto load_buildfiles = [&m, &d, erp] (const path& b,
+                                          const path& r,
+                                          const dir_path& c,
+                                          const string& ext)
+    {
+      auto diag_path = [&d, erp] (const path& p)
+      {
+        return !erp ? p : p.leaf (d);
+      };
+
+      auto load = [&diag_path] (const path& f)
+      {
+        try
+        {
+          ifdstream ifs (f);
+          string r (ifs.read_text ());
+          ifs.close ();
+          return r;
+        }
+        catch (const io_error& e)
+        {
+          // Sanitize the exception description.
+          //
+          ostringstream os;
+          os << "unable to read from " << diag_path (f) << ": " << e;
+          throw runtime_error (os.str ());
+        }
+      };
+
+      if (!m.bootstrap_build)
+        m.bootstrap_build = load (b);
+
+      if (!m.root_build && exists (r))
+        m.root_build = load (r);
+
+      if (m.root_build && exists (c))
+      try
+      {
+        for (auto& f: find_buildfiles (c, ext, m.buildfiles))
+          m.buildfiles.emplace_back (move (f.second), load (f.first));
+      }
+      catch (const system_error& e)
+      {
+        // Sanitize the exception description.
+        //
+        ostringstream os;
+        os << "unable to scan directory " << diag_path (c) << ": " << e;
+        throw runtime_error (os.str ());
+      }
+    };
+
+    // Set the manifest's alt_naming flag to the deduced value if absent and
+    // verify that it matches otherwise.
+    //
+    auto alt_naming = [&m, &d, erp] (bool v)
+    {
+      if (!m.alt_naming)
+      {
+        m.alt_naming = v;
+      }
+      else if (*m.alt_naming != v)
+      {
+        string e ("buildfile naming scheme mismatch between manifest and "
+                  "package directory");
+
+        if (!erp)
+          e += " " + d.string ();
+
+        throw runtime_error (e);
+      }
+    };
+
+    // Check the alternative bootstrap file first since it is more specific.
+    //
+    path bf;
+    if (exists (bf = d / alt_bootstrap_file))
+    {
+      alt_naming (true);
+
+      load_buildfiles (bf,
+                       d / alt_root_file,
+                       d / alt_config_dir,
+                       alt_build_ext);
+    }
+    else if (exists (bf = d / std_bootstrap_file))
+    {
+      alt_naming (false);
+
+      load_buildfiles (bf,
+                       d / std_root_file,
+                       d / std_config_dir,
+                       std_build_ext);
+    }
+    else
+    {
+      string e ("unable to find bootstrap.build file in package directory");
+
+      if (!erp)
+        e += " " + d.string ();
+
+      throw runtime_error (e);
+    }
+  }
 }
diff --git a/bpkg/manifest-utility.hxx b/bpkg/manifest-utility.hxx
index 8701b65..abb85ab 100644
--- a/bpkg/manifest-utility.hxx
+++ b/bpkg/manifest-utility.hxx
@@ -154,14 +154,29 @@ namespace bpkg
                     const dir_path& src_dir,
                     const package_info*);
 
-  // Caclulate the checksum of the buildfiles using the *-build manifest
-  // values, unless unspecified in which case use the files in the package
-  // source directory.
+  // Calculate the checksum of the buildfiles using the *-build manifest
+  // values. If the package source directory is specified (not empty), then
+  // use the files it contains for unspecified values. If the alt_naming flag
+  // is also specified for the latter case, then verify the package's
+  // buildfile naming scheme against its value and fail on mismatch.
   //
   string
   package_buildfiles_checksum (const optional<string>& bootstrap_build,
                                const optional<string>& root_build,
-                               const dir_path& src_dir);
+                               const vector<buildfile>& buildfiles,
+                               const dir_path& src_dir = {},
+                               optional<bool> alt_naming = nullopt);
+
+  // Load the package's buildfiles for unspecified manifest values. Throw
+  // std::runtime_error for underlying errors (unable to find bootstrap.build,
+  // unable to read from file, etc). Optionally convert paths used in the
+  // potential error description to be relative to the package source
+  // directory.
+  //
+  void
+  load_package_buildfiles (package_manifest&,
+                           const dir_path& src_dir,
+                           bool err_path_relative = false);
 }
 
 #endif // BPKG_MANIFEST_UTILITY_HXX
diff --git a/bpkg/package-skeleton.cxx b/bpkg/package-skeleton.cxx
index d58c846..a3e0b5a 100644
--- a/bpkg/package-skeleton.cxx
+++ b/bpkg/package-skeleton.cxx
@@ -2501,7 +2501,10 @@ namespace bpkg
         // additional files.
         //
         {
-          path bf (skl.src_root_ / std_bootstrap_file);
+          bool an (*ap.alt_naming);
+
+          path bf (skl.src_root_ /
+                   (an ? alt_bootstrap_file : std_bootstrap_file));
 
           mk_p (bf.directory ());
 
@@ -2524,7 +2527,22 @@ namespace bpkg
           save (*ap.bootstrap_build, bf);
 
           if (ap.root_build)
-            save (*ap.root_build, skl.src_root_ / std_root_file);
+            save (*ap.root_build,
+                  skl.src_root_ / (an ? alt_root_file : std_root_file));
+
+          for (const buildfile& f: ap.buildfiles)
+          {
+            path p (skl.src_root_                        /
+                    (an ? alt_build_dir : std_build_dir) /
+                    f.path);
+
+            p += ".";
+            p += (an ? alt_build_ext : std_build_ext);
+
+            mk_p (p.directory ());
+
+            save (f.content, p);
+          }
         }
 
         // Create the manifest file containing the bare minimum of values
diff --git a/bpkg/package.cxx b/bpkg/package.cxx
index c02bdf4..a7282c5 100644
--- a/bpkg/package.cxx
+++ b/bpkg/package.cxx
@@ -676,6 +676,7 @@ namespace bpkg
       changed = package_buildfiles_checksum (
         nullopt /* bootstrap_build */,
         nullopt /* root_build */,
+        {}      /* buildfiles */,
         d) != *p->buildfiles_checksum;
     }
 
diff --git a/bpkg/package.hxx b/bpkg/package.hxx
index dc5031c..694d068 100644
--- a/bpkg/package.hxx
+++ b/bpkg/package.hxx
@@ -27,7 +27,7 @@
 //
 #define DB_SCHEMA_VERSION_BASE 7
 
-#pragma db model version(DB_SCHEMA_VERSION_BASE, 19, closed)
+#pragma db model version(DB_SCHEMA_VERSION_BASE, 20, closed)
 
 namespace bpkg
 {
@@ -653,6 +653,10 @@ namespace bpkg
     available_package_id (package_name, const bpkg::version&);
   };
 
+  // buildfile
+  //
+  #pragma db value(buildfile) definition
+
   #pragma db object pointer(shared_ptr) session
   class available_package
   {
@@ -690,12 +694,14 @@ namespace bpkg
     small_vector<test_dependency, 1> tests;
 
     // Note that while the bootstrap buildfile is always present for stub
-    // packages, we don't save bootstrap/root buildfiles for stubs of any kind
-    // (can come from repository, be based on system selected package, etc),
-    // leaving *_build as nullopt.
+    // packages, we don't save buildfiles for stubs of any kind (can come from
+    // repository, be based on system selected package, etc), leaving *_build
+    // as nullopt and buildfiles empty.
     //
-    optional<string> bootstrap_build;
-    optional<string> root_build;
+    optional<bool>    alt_naming;
+    optional<string>  bootstrap_build;
+    optional<string>  root_build;
+    vector<buildfile> buildfiles;
 
     // Present for non-transient objects only (and only for certain repository
     // types).
@@ -719,10 +725,12 @@ namespace bpkg
     {
       if (!stub ())
       {
-        assert (m.bootstrap_build.has_value ());
+        assert (m.bootstrap_build.has_value () && m.alt_naming.has_value ());
 
+        alt_naming = m.alt_naming;
         bootstrap_build = move (m.bootstrap_build);
         root_build = move (m.root_build);
+        buildfiles = move (m.buildfiles);
       }
     }
 
@@ -813,6 +821,20 @@ namespace bpkg
     //
     #pragma db member(tests) id_column("") value_column("test_")
 
+    // alt_naming
+    //
+    // @@ TMP Drop when database migration to the schema version 20 is no
+    //    longer supported.
+    //
+    //    Note that since no real packages with alternative buildfile naming
+    //    use conditional dependencies yet, we can just set alt_naming to
+    //    false during migration to the database schema version 20. Also we
+    //    never rely on alt_naming to be nullopt for the stub packages, so
+    //    let's not complicate things and set alt_naming to false for them
+    //    either.
+    //
+    #pragma db member(alt_naming) default(false)
+
     // *_build
     //
     // @@ TMP Drop when database migration to the schema version 15 is no
@@ -827,6 +849,10 @@ namespace bpkg
     //
     #pragma db member(bootstrap_build) default("")
 
+    // buildfiles
+    //
+    #pragma db member(buildfiles) id_column("") value_column("")
+
   private:
     friend class odb::access;
     available_package () = default;
diff --git a/bpkg/package.xml b/bpkg/package.xml
index 8959529..3fa1bc0 100644
--- a/bpkg/package.xml
+++ b/bpkg/package.xml
@@ -1,4 +1,48 @@
 <changelog xmlns="http://www.codesynthesis.com/xmlns/odb/changelog" database="sqlite" version="1">
+  <changeset version="20">
+    <alter-table name="main.available_package">
+      <add-column name="alt_naming" type="INTEGER" null="true" default="0"/>
+    </alter-table>
+    <add-table name="main.available_package_buildfiles" kind="container">
+      <column name="name" type="TEXT" null="true" options="COLLATE NOCASE"/>
+      <column name="version_epoch" type="INTEGER" null="true"/>
+      <column name="version_canonical_upstream" type="TEXT" null="true"/>
+      <column name="version_canonical_release" type="TEXT" null="true" options="COLLATE BINARY"/>
+      <column name="version_revision" type="INTEGER" null="true"/>
+      <column name="version_iteration" type="INTEGER" null="true"/>
+      <column name="index" type="INTEGER" null="true"/>
+      <column name="path" type="TEXT" null="true"/>
+      <column name="content" type="TEXT" null="true"/>
+      <foreign-key name="object_id_fk" on-delete="CASCADE">
+        <column name="name"/>
+        <column name="version_epoch"/>
+        <column name="version_canonical_upstream"/>
+        <column name="version_canonical_release"/>
+        <column name="version_revision"/>
+        <column name="version_iteration"/>
+        <references table="main.available_package">
+          <column name="name"/>
+          <column name="version_epoch"/>
+          <column name="version_canonical_upstream"/>
+          <column name="version_canonical_release"/>
+          <column name="version_revision"/>
+          <column name="version_iteration"/>
+        </references>
+      </foreign-key>
+      <index name="available_package_buildfiles_object_id_i">
+        <column name="name"/>
+        <column name="version_epoch"/>
+        <column name="version_canonical_upstream"/>
+        <column name="version_canonical_release"/>
+        <column name="version_revision"/>
+        <column name="version_iteration"/>
+      </index>
+      <index name="available_package_buildfiles_index_i">
+        <column name="index"/>
+      </index>
+    </add-table>
+  </changeset>
+
   <changeset version="19">
     <alter-table name="main.selected_package_prerequisites">
       <add-column name="config_dependency_index" type="INTEGER" null="true" default="0"/>
diff --git a/bpkg/pkg-checkout.cxx b/bpkg/pkg-checkout.cxx
index 6c6dcf8..2a3f508 100644
--- a/bpkg/pkg-checkout.cxx
+++ b/bpkg/pkg-checkout.cxx
@@ -319,12 +319,15 @@ namespace bpkg
       // Calculate the buildfiles checksum if the package has any buildfile
       // clauses in the dependencies.
       //
+      // Note that the available package already has all the buildfiles
+      // loaded.
+      //
       if ((p != nullptr && p->manifest_checksum == mc)
           ? p->buildfiles_checksum.has_value ()
           : has_buildfile_clause (ap->dependencies))
         bc = package_buildfiles_checksum (ap->bootstrap_build,
                                           ap->root_build,
-                                          d);
+                                          ap->buildfiles);
     }
 
     if (p != nullptr)
diff --git a/bpkg/pkg-unpack.cxx b/bpkg/pkg-unpack.cxx
index b38a750..2e21c70 100644
--- a/bpkg/pkg-unpack.cxx
+++ b/bpkg/pkg-unpack.cxx
@@ -175,6 +175,7 @@ namespace bpkg
           : has_buildfile_clause (deps))
         bc = package_buildfiles_checksum (nullopt /* bootstrap_build */,
                                           nullopt /* root_build */,
+                                          {}      /* buildfiles */,
                                           d);
     }
 
@@ -414,10 +415,13 @@ namespace bpkg
 
       if (ap != nullptr)
       {
+        // Note that the available package already has all the buildfiles
+        // loaded.
+        //
         if (has_buildfile_clause (ap->dependencies))
           bc = package_buildfiles_checksum (ap->bootstrap_build,
                                             ap->root_build,
-                                            d);
+                                            ap->buildfiles);
       }
       else
       {
@@ -435,7 +439,9 @@ namespace bpkg
         if (has_buildfile_clause (m.dependencies))
           bc = package_buildfiles_checksum (m.bootstrap_build,
                                             m.root_build,
-                                            d);
+                                            m.buildfiles,
+                                            d,
+                                            m.alt_naming);
       }
     }
 
diff --git a/bpkg/pkg-verify.cxx b/bpkg/pkg-verify.cxx
index b0dbf65..229b73d 100644
--- a/bpkg/pkg-verify.cxx
+++ b/bpkg/pkg-verify.cxx
@@ -226,12 +226,13 @@ namespace bpkg
             iu);
         }
 
-        // Extract the bootstrap/root buildfiles into the respective *-build
-        // values, if requested and are not already specified in the manifest.
+        // Extract the bootstrap, root, and config/*.build buildfiles into the
+        // respective *-build values, if requested and are not already
+        // specified in the manifest.
         //
         // Note that we don't verify that the files are not empty.
         //
-        if (lb && (!m.bootstrap_build || !m.root_build))
+        if (lb)
         {
           paths ps (archive_contents (co, af, diag_level != 0));
 
@@ -240,14 +241,80 @@ namespace bpkg
             return find (ps.begin (), ps.end (), p) != ps.end ();
           };
 
-          auto extract_buildfiles = [&m, &co, &af, diag_level, &contains]
-                                    (const path& b, const path& r)
+          auto extract_buildfiles = [&m, &co, &af, &ps, diag_level, &contains]
+                                    (const path& b,
+                                     const path& r,
+                                     const dir_path& c,
+                                     const string& ext)
           {
             if (!m.bootstrap_build)
               m.bootstrap_build = extract (co, af, b, diag_level != 0);
 
             if (!m.root_build && contains (r))
               m.root_build = extract (co, af, r, diag_level != 0);
+
+            // Extract build/config/*.build files.
+            //
+            if (m.root_build)
+            {
+              vector<buildfile>& bs (m.buildfiles);
+              size_t n (bs.size ());
+
+              for (const path& ap: ps)
+              {
+                if (!ap.to_directory () && ap.sub (c))
+                {
+                  path p (ap.leaf (c));
+                  const char* e (p.extension_cstring ());
+
+                  // Only consider immediate sub-entries of the config/
+                  // subdirectory.
+                  //
+                  if (e != nullptr && ext == e && p.simple ())
+                  {
+                    path f (c.leaf () / p.base ()); // Relative to build/.
+
+                    if (find_if (bs.begin (), bs.end (),
+                                 [&f] (const auto& v) {return v.path == f;}) ==
+                        bs.end ())
+                    {
+                      bs.emplace_back (move (f),
+                                       extract (co, af, ap, diag_level != 0));
+                    }
+                  }
+                }
+              }
+
+              // To produce a stable result sort the appended *-build values.
+              //
+              if (bs.size () != n)
+              {
+                sort (bs.begin () + n, bs.end (),
+                      [] (const auto& x, const auto& y)
+                      {
+                        return x.path < y.path;
+                      });
+              }
+            }
+          };
+
+          // Set the manifest's alt_naming flag to the deduced value if absent
+          // and verify that it matches otherwise.
+          //
+          auto alt_naming = [&m, diag_level, &af] (bool v)
+          {
+            if (!m.alt_naming)
+            {
+              m.alt_naming = v;
+            }
+            else if (*m.alt_naming != v)
+            {
+              if (diag_level != 0)
+                error << "buildfile naming scheme mismatch between manifest "
+                      << "and package archive " << af;
+
+              throw failed ();
+            }
           };
 
           // Check the alternative bootstrap file first since it is more
@@ -256,11 +323,21 @@ namespace bpkg
           path bf;
           if (contains (bf = pd / alt_bootstrap_file))
           {
-            extract_buildfiles (bf, pd / alt_root_file);
+            alt_naming (true);
+
+            extract_buildfiles (bf,
+                                pd / alt_root_file,
+                                pd / alt_config_dir,
+                                alt_build_ext);
           }
           else if (contains (bf = pd / std_bootstrap_file))
           {
-            extract_buildfiles (bf, pd / std_root_file);
+            alt_naming (false);
+
+            extract_buildfiles (bf,
+                                pd / std_root_file,
+                                pd / std_config_dir,
+                                std_build_ext);
           }
           else
           {
@@ -354,61 +431,23 @@ namespace bpkg
                           tf,
                           iu);
 
-      // Load the bootstrap/root buildfiles into the respective *-build
-      // values, if requested and if they are not already specified in the
-      // manifest.
+      // Load the bootstrap, root, and config/*.build buildfiles into the
+      // respective *-build values, if requested and if they are not already
+      // specified in the manifest.
       //
       // Note that we don't verify that the files are not empty.
       //
-      if (lb && (!m.bootstrap_build || !m.root_build))
+      if (lb)
+      try
       {
-        auto load_buildfiles = [&m, diag_level] (const path& b, const path& r)
-        {
-          auto load = [diag_level] (const path& f)
-          {
-            try
-            {
-              ifdstream ifs (f);
-              string r (ifs.read_text ());
-              ifs.close ();
-              return r;
-            }
-            catch (const io_error& e)
-            {
-              if (diag_level != 0)
-                error << "unable to read from " << f << ": " << e;
-
-              throw failed ();
-            }
-          };
-
-          if (!m.bootstrap_build)
-            m.bootstrap_build = load (b);
-
-          if (!m.root_build && exists (r))
-            m.root_build = load (r);
-        };
-
-        // Check the alternative bootstrap file first since it is more
-        // specific.
-        //
-        path bf;
-        if (exists (bf = d / alt_bootstrap_file))
-        {
-          load_buildfiles (bf, d / alt_root_file);
-        }
-        else if (exists (bf = d / std_bootstrap_file))
-        {
-          load_buildfiles (bf, d / std_root_file);
-        }
-        else
-        {
-          if (diag_level != 0)
-            error << "unable to find bootstrap.build file in package "
-                  << "directory " << d;
+        load_package_buildfiles (m, d);
+      }
+      catch (const runtime_error& e)
+      {
+        if (diag_level != 0)
+          error << e;
 
-          throw failed ();
-        }
+        throw failed ();
       }
 
       // We used to verify package directory is <name>-<version> but it is
diff --git a/bpkg/pkg-verify.hxx b/bpkg/pkg-verify.hxx
index 8c0b555..b4b536b 100644
--- a/bpkg/pkg-verify.hxx
+++ b/bpkg/pkg-verify.hxx
@@ -22,8 +22,9 @@ namespace bpkg
   // expand the file-referencing manifest values (description, changes, etc),
   // setting them to the contents of files they refer to, set the potentially
   // absent description-type value to the effective description type (see
-  // libbpkg/manifest.hxx), load the bootstrap and root buildfiles into the
-  // respective *-build values, and complete the dependency constraints.
+  // libbpkg/manifest.hxx), load the bootstrap, root, and config/*.build
+  // buildfiles into the respective *-build values, and complete the
+  // dependency constraints.
   //
   // Throw not_package (derived from failed) if this doesn't look like a
   // package. Throw plain failed if this does looks like a package but
diff --git a/bpkg/rep-fetch.cxx b/bpkg/rep-fetch.cxx
index e9cacd0..038d54e 100644
--- a/bpkg/rep-fetch.cxx
+++ b/bpkg/rep-fetch.cxx
@@ -323,67 +323,21 @@ namespace bpkg
         //
         m.location = move (*pm.location);
 
-        // Load the bootstrap/root buildfiles into the respective *-build
-        // values, if requested and if they are not already specified in the
-        // manifest.
+        // Load the bootstrap, root, and config/*.build buildfiles into the
+        // respective *-build values, if requested and if they are not already
+        // specified in the manifest.
         //
-        if (lb && (!m.bootstrap_build || !m.root_build))
+        if (lb)
+        try
         {
-          const dir_path& d (pds[i]);
-
-          // Note that the paths relative to the package directory (last two
-          // arguments) are used for diagnostics only.
-          //
-          auto load_buildfiles = [&m, &add_package_info] (const path& bf,
-                                                          const path& rf,
-                                                          const path& bfr,
-                                                          const path& rfr)
-          {
-            auto load = [&m, &add_package_info] (const path& f, const path& fr)
-            {
-              try
-              {
-                ifdstream ifs (f);
-                string r (ifs.read_text ());
-                ifs.close ();
-                return r;
-              }
-              catch (const io_error& e)
-              {
-                diag_record dr (fail);
-                dr << "unable to read from " << fr << ": " << e;
-                add_package_info (m, dr);
-                dr << endf;
-              }
-            };
-
-            if (!m.bootstrap_build)
-              m.bootstrap_build = load (bf, bfr);
-
-            if (!m.root_build && exists (rf))
-              m.root_build = load (rf, rfr);
-          };
-
-          // Check the alternative bootstrap file first since it is more
-          // specific.
-          //
-          path bf;
-          if (exists (bf = d / alt_bootstrap_file))
-          {
-            load_buildfiles (bf, d / alt_root_file,
-                             alt_bootstrap_file, alt_root_file);
-          }
-          else if (exists (bf = d / std_bootstrap_file))
-          {
-            load_buildfiles (bf, d / std_root_file,
-                             std_bootstrap_file, std_root_file);
-          }
-          else
-          {
-            diag_record dr (fail);
-            dr << "unable to find bootstrap.build file";
-            add_package_info (m, dr);
-          }
+          load_package_buildfiles (m, pds[i], true /* err_path_relative */);
+        }
+        catch (const runtime_error& e)
+        {
+          diag_record dr (fail);
+          dr << e << info;
+          add_package_info (m, dr);
+          dr << endf;
         }
 
         pm = move (m);
diff --git a/bpkg/rep-fetch.hxx b/bpkg/rep-fetch.hxx
index b9d458f..7e03999 100644
--- a/bpkg/rep-fetch.hxx
+++ b/bpkg/rep-fetch.hxx
@@ -54,9 +54,9 @@ namespace bpkg
   // (description, changes, etc), setting them to the contents of files they
   // refer to and set the potentially absent description-type value to the
   // effective description type (see libbpkg/manifest.hxx) and load the
-  // bootstrap and root buildfiles into the respective *-build values. Note
-  // that for pkg repositories such values are expanded/loaded at the
-  // repository creation time.
+  // bootstrap, root, and config/*.build buildfiles into the respective *-build
+  // values. Note that for pkg repositories such values are expanded/loaded at
+  // the repository creation time.
   //
   rep_fetch_data
   rep_fetch (const common_options&,
diff --git a/bpkg/utility.cxx b/bpkg/utility.cxx
index d229205..68d79ad 100644
--- a/bpkg/utility.cxx
+++ b/bpkg/utility.cxx
@@ -26,13 +26,23 @@ namespace bpkg
   const dir_path certs_dir (dir_path (bpkg_dir) /= "certs");
   const dir_path repos_dir (dir_path (bpkg_dir) /= "repos");
 
+  // Standard and alternative build file/directory naming schemes.
+  //
+  // build:
+  //
   const dir_path std_build_dir      ("build");
+  const dir_path std_config_dir     (dir_path (std_build_dir) /= "config");
   const path     std_bootstrap_file (dir_path (std_build_dir) /= "bootstrap.build");
   const path     std_root_file      (dir_path (std_build_dir) /= "root.build");
+  const string   std_build_ext      ("build");
 
+  // build2:
+  //
   const dir_path alt_build_dir      ("build2");
+  const dir_path alt_config_dir     (dir_path (alt_build_dir) /= "config");
   const path     alt_bootstrap_file (dir_path (alt_build_dir) /= "bootstrap.build2");
   const path     alt_root_file      (dir_path (alt_build_dir) /= "root.build2");
+  const string   alt_build_ext      ("build2");
 
   const dir_path current_dir (".");
 
diff --git a/bpkg/utility.hxx b/bpkg/utility.hxx
index 597800c..342d608 100644
--- a/bpkg/utility.hxx
+++ b/bpkg/utility.hxx
@@ -86,12 +86,16 @@ namespace bpkg
   extern const dir_path repos_dir;          // .bpkg/repos/
 
   extern const dir_path std_build_dir;      // build/
+  extern const dir_path std_config_dir;     // build/config/
   extern const path     std_bootstrap_file; // build/bootstrap.build
   extern const path     std_root_file;      // build/root.build
+  extern const string   std_build_ext;      // build
 
   extern const dir_path alt_build_dir;      // build2/
+  extern const dir_path alt_config_dir;     // build2/config/
   extern const path     alt_bootstrap_file; // build2/bootstrap.build2
   extern const path     alt_root_file;      // build2/root.build2
+  extern const string   alt_build_ext;      // build2
 
   extern const dir_path current_dir;        // ./
 
diff --git a/doc/manual.cli b/doc/manual.cli
index b00430a..ec0a535 100644
--- a/doc/manual.cli
+++ b/doc/manual.cli
@@ -623,6 +623,11 @@ license: <licenses> [; <comment>]
 
 [bootstrap-build]: <text>
 [root-build]: <text>
+[*-build]: <text>
+
+[bootstrap-build2]: <text>
+[root-build2]: <text>
+[*-build2]: <text>
 \
 
 \h2#manifest-package-name|\c{name}|
@@ -1437,17 +1442,51 @@ Note that the comment of the matching exclusion is used by the web interface
 (\c{brep}) to display the reason for the build configuration exclusion.
 
 
-\h2#manifest-package-bootstrap-root-build|\c{{bootstrap,root\}-build}|
+\h2#manifest-package-x-build|\c{{bootstrap,root,*\}-build[2]}|
 
 \
 [bootstrap-build]: <text>
 [root-build]: <text>
+[*-build]: <text>
+
+[bootstrap-build2]: <text>
+[root-build2]: <text>
+[*-build2]: <text>
+\
+
+The contents of the mandatory \c{bootstrap.build} file, optional
+\c{root.build} file, and additional files included by \c{root.build}, or their
+alternative naming scheme variants (\c{bootstrap.build2}, etc). Packages with
+the alternative naming scheme should use the \c{*-build2} values instead of
+\c{*-build}.
+
+These files must reside in the package's \c{build/} subdirectory and have the
+\c{.build} extension (or their alternative names). The respective manifest
+value name prefix must be the file path relative to this subdirectory with the
+extension stripped.
+
+As an example, the following value corresponds to the
+\c{build/config/common.build} file:
+
+\
+config/common-build:\
+config [bool] config.libhello.fancy ?= false
+\\
+\
+
+And the following value corresponds to the \c{build2/config/common.build2}
+file in a package with the alternative naming scheme:
+
+\
+config/common-build2:\
+config [bool] config.libhello.fancy ?= false
+\\
 \
 
-The contents of the mandatory \c{bootstrap.build} and optional \c{root.build}
-files in the package's \c{build/} (or their alternative names) subdirectory.
-If unspecified, then they will be automatically added, for example, when the
-\l{#manifest-package-list-pkg package list manifest} is created.
+If unspecified, then the package's \c{bootstrap.build}, \c{root.build}, and
+\c{build/config/*.build} files (or their alternative names) will be
+automatically added, for example, when the \l{#manifest-package-list-pkg
+package list manifest} is created.
 
 
 \h#manifest-package-list-pkg|Package List Manifest for \cb{pkg} Repositories|
diff --git a/tests/common/dependency-alternatives/t11a/libbar-1.0.0.tar.gz b/tests/common/dependency-alternatives/t11a/libbar-1.0.0.tar.gz
index 7c5a840..aacf8d7 100644
--- a/tests/common/dependency-alternatives/t11a/libbar-1.0.0.tar.gz
+++ b/tests/common/dependency-alternatives/t11a/libbar-1.0.0.tar.gz
diff --git a/tests/common/dependency-alternatives/t11a/libfoo-1.0.0.tar.gz b/tests/common/dependency-alternatives/t11a/libfoo-1.0.0.tar.gz
index 52ba91b..da545c1 100644
--- a/tests/common/dependency-alternatives/t11a/libfoo-1.0.0.tar.gz
+++ b/tests/common/dependency-alternatives/t11a/libfoo-1.0.0.tar.gz
diff --git a/tests/pkg-build.testscript b/tests/pkg-build.testscript
index 86a63f1..bf39949 100644
--- a/tests/pkg-build.testscript
+++ b/tests/pkg-build.testscript
@@ -4932,7 +4932,7 @@ test.options += --no-progress
     }
   }
 
-  : configuration-negotiation-order
+  : config-negotiation-order
   :
   {
     +$clone_root_cfg && $rep_add $rep/t11a && $rep_fetch
@@ -5520,7 +5520,7 @@ test.options += --no-progress
         $pkg_drop foo libfoo
       }
 
-      : dependent-single-position
+      : dependent-single-pos
       :
       {
         +$clone_cfg
@@ -5831,7 +5831,7 @@ test.options += --no-progress
         }
       }
 
-      : dependent-multiple-positions
+      : dependent-mult-pos
       :
       {
         +$clone_cfg
@@ -6151,7 +6151,7 @@ test.options += --no-progress
           $pkg_drop tex baz
         }
 
-        : replace-re-evaluation
+        : replace-reeval
         :
         {
           +$clone_cfg
@@ -11272,7 +11272,7 @@ test.options += --no-progress
     }
   }
 
-  : configuration-negotiation
+  : config-negotiation
   :
   {
     test.arguments += --yes --plan 'build plan:'