Add support for package build configurations

11 files changed, 478 insertions, 73 deletions

diff --git a/libbrep/build-extra.sql b/libbrep/build-extra.sql
index 2c204e6..7331ab1 100644
--- a/libbrep/build-extra.sql
+++ b/libbrep/build-extra.sql
@@ -6,6 +6,12 @@
 -- package-extra.sql file for details.
 --
 
+DROP FOREIGN TABLE IF EXISTS build_package_config_constraints;
+
+DROP FOREIGN TABLE IF EXISTS build_package_config_builds;
+
+DROP FOREIGN TABLE IF EXISTS build_package_configs;
+
 DROP FOREIGN TABLE IF EXISTS build_package_constraints;
 
 DROP FOREIGN TABLE IF EXISTS build_package_builds;
@@ -60,7 +66,7 @@ CREATE FOREIGN TABLE build_package (
 SERVER package_server OPTIONS (table_name 'package');
 
 -- The foreign tables for the build_package object requirements member (that
--- is of a 2-dimensional container type).
+-- is of a 3-dimensional container type).
 --
 CREATE FOREIGN TABLE build_package_requirements (
   tenant TEXT NOT NULL,
@@ -168,3 +174,47 @@ CREATE FOREIGN TABLE build_package_constraints (
   target TEXT NULL,
   comment TEXT NOT NULL)
 SERVER package_server OPTIONS (table_name 'package_build_constraints');
+
+-- The foreign tables for the build_package object configs member (that is a
+-- container of values containing containers.
+--
+CREATE FOREIGN TABLE build_package_configs (
+  tenant TEXT NOT NULL,
+  name CITEXT NOT NULL,
+  version_epoch INTEGER NOT NULL,
+  version_canonical_upstream TEXT NOT NULL,
+  version_canonical_release TEXT NOT NULL COLLATE "C",
+  version_revision INTEGER NOT NULL,
+  index BIGINT NOT NULL,
+  config_name TEXT NOT NULL,
+  config_arguments TEXT NULL,
+  config_comment TEXT NOT NULL)
+SERVER package_server OPTIONS (table_name 'package_build_configs');
+
+CREATE FOREIGN TABLE build_package_config_builds (
+  tenant TEXT NOT NULL,
+  name CITEXT NOT NULL,
+  version_epoch INTEGER NOT NULL,
+  version_canonical_upstream TEXT NOT NULL,
+  version_canonical_release TEXT NOT NULL COLLATE "C",
+  version_revision INTEGER NOT NULL,
+  config_index BIGINT NOT NULL,
+  index BIGINT NOT NULL,
+  expression TEXT NOT NULL,
+  comment TEXT NOT NULL)
+SERVER package_server OPTIONS (table_name 'package_build_config_builds');
+
+CREATE FOREIGN TABLE build_package_config_constraints (
+  tenant TEXT NOT NULL,
+  name CITEXT NOT NULL,
+  version_epoch INTEGER NOT NULL,
+  version_canonical_upstream TEXT NOT NULL,
+  version_canonical_release TEXT NOT NULL COLLATE "C",
+  version_revision INTEGER NOT NULL,
+  config_index BIGINT NOT NULL,
+  index BIGINT NOT NULL,
+  exclusion BOOLEAN NOT NULL,
+  config TEXT NOT NULL,
+  target TEXT NULL,
+  comment TEXT NOT NULL)
+SERVER package_server OPTIONS (table_name 'package_build_config_constraints');
diff --git a/libbrep/build-package.hxx b/libbrep/build-package.hxx
index 54edc2b..79fb6a4 100644
--- a/libbrep/build-package.hxx
+++ b/libbrep/build-package.hxx
@@ -120,11 +120,12 @@ namespace brep
     lazy_shared_ptr<build_repository> internal_repository;
     bool buildable;
 
-    // Mapped to the package object builds and build_constraints members using
-    // the PostgreSQL foreign table mechanism.
+    // Mapped to the package object builds, build_constraints, and
+    // build_configs members using the PostgreSQL foreign table mechanism.
     //
-    build_class_exprs builds;
-    build_constraints constraints;
+    build_class_exprs     builds;
+    build_constraints     constraints;
+    build_package_configs configs;
 
     bool
     internal () const noexcept {return internal_repository != nullptr;}
@@ -146,9 +147,6 @@ namespace brep
 
     // Container of the requirement_alternative values.
     //
-    #pragma db member(requirement_alternative_key::outer) column("requirement_index")
-    #pragma db member(requirement_alternative_key::inner) column("index")
-
     #pragma db member(requirement_alternatives)               \
       virtual(requirement_alternatives_map)                   \
       after(requirements)                                     \
@@ -158,10 +156,6 @@ namespace brep
 
     // Container of the requirement (string) values.
     //
-    #pragma db member(requirement_key::outer)  column("requirement_index")
-    #pragma db member(requirement_key::middle) column("alternative_index")
-    #pragma db member(requirement_key::inner)  column("index")
-
     #pragma db member(requirement_alternative_requirements)    \
       virtual(requirement_alternative_requirements_map)        \
       after(requirement_alternatives)                          \
@@ -175,6 +169,34 @@ namespace brep
     #pragma db member(builds) id_column("") value_column("")
     #pragma db member(constraints) id_column("") value_column("")
 
+    // configs
+    //
+    // Note that build_package_config::{builds,constraints} are
+    // persisted/loaded via the separate nested containers (see commons.hxx
+    // for details).
+    //
+    #pragma db member(configs) id_column("") value_column("config_")
+
+    #pragma db member(config_builds)                           \
+      virtual(build_class_exprs_map)                           \
+      after(configs)                                           \
+      get(odb::nested_get (                                    \
+            brep::build_package_config_builds (this.configs))) \
+      set(brep::build_package_config_builds bs;                \
+          odb::nested_set (bs, std::move (?));                 \
+          move (bs).to_configs (this.configs))                 \
+      id_column("") key_column("") value_column("")
+
+    #pragma db member(config_constraints)                           \
+      virtual(build_constraints_map)                                \
+      after(config_builds)                                          \
+      get(odb::nested_get (                                         \
+            brep::build_package_config_constraints (this.configs))) \
+      set(brep::build_package_config_constraints cs;                \
+          odb::nested_set (cs, std::move (?));                      \
+          move (cs).to_configs (this.configs))                      \
+      id_column("") key_column("") value_column("")
+
   private:
     friend class odb::access;
     build_package () = default;
diff --git a/libbrep/build.cxx b/libbrep/build.cxx
index c095b32..c8a2cd1 100644
--- a/libbrep/build.cxx
+++ b/libbrep/build.cxx
@@ -57,8 +57,9 @@ namespace brep
   build (string tnt,
          package_name_type pnm,
          version pvr,
-         string cfg,
          target_triplet trg,
+         string tcf,
+         string pcf,
          string tnm, version tvr,
          optional<string> inr,
          optional<string> afp, optional<string> ach,
@@ -66,14 +67,16 @@ namespace brep
          string ccs,
          string mcs)
       : id (package_id (move (tnt), move (pnm), pvr),
-            move (cfg),
             move (trg),
+            move (tcf),
+            move (pcf),
             move (tnm), tvr),
         tenant (id.package.tenant),
         package_name (id.package.name),
         package_version (move (pvr)),
-        configuration (id.configuration),
         target (id.target),
+        target_config_name (id.target_config_name),
+        package_config_name (id.package_config_name),
         toolchain_name (id.toolchain_name),
         toolchain_version (move (tvr)),
         state (build_state::building),
@@ -93,19 +96,22 @@ namespace brep
   build_delay::
   build_delay (string tnt,
                package_name_type pnm, version pvr,
-               string cfg,
                target_triplet trg,
+               string tcf,
+               string pcf,
                string tnm, version tvr,
                timestamp ptm)
       : id (package_id (move (tnt), move (pnm), pvr),
-            move (cfg),
             move (trg),
+            move (tcf),
+            move (pcf),
             move (tnm), tvr),
         tenant (id.package.tenant),
         package_name (id.package.name),
         package_version (move (pvr)),
-        configuration (id.configuration),
         target (id.target),
+        target_config_name (id.target_config_name),
+        package_config_name (id.package_config_name),
         toolchain_name (id.toolchain_name),
         toolchain_version (move (tvr)),
         package_timestamp (ptm)
diff --git a/libbrep/build.hxx b/libbrep/build.hxx
index ceea81a..dfd0e55 100644
--- a/libbrep/build.hxx
+++ b/libbrep/build.hxx
@@ -26,9 +26,9 @@
 
 // Used by the data migration entries.
 //
-#define LIBBREP_BUILD_SCHEMA_VERSION_BASE 19
+#define LIBBREP_BUILD_SCHEMA_VERSION_BASE 20
 
-#pragma db model version(LIBBREP_BUILD_SCHEMA_VERSION_BASE, 19, closed)
+#pragma db model version(LIBBREP_BUILD_SCHEMA_VERSION_BASE, 20, closed)
 
 // We have to keep these mappings at the global scope instead of inside the
 // brep namespace because they need to be also effective in the bbot namespace
@@ -44,20 +44,23 @@ namespace brep
   struct build_id
   {
     package_id package;
-    string configuration;
     target_triplet target;
+    string target_config_name;
+    string package_config_name;
     string toolchain_name;
     canonical_version toolchain_version;
 
     build_id () = default;
     build_id (package_id p,
-              string c,
               target_triplet t,
+              string tc,
+              string pc,
               string n,
               const brep::version& v)
         : package (move (p)),
-          configuration (move (c)),
           target (move (t)),
+          target_config_name (move (tc)),
+          package_config_name (move (pc)),
           toolchain_name (move (n)),
           toolchain_version (v) {}
   };
@@ -68,10 +71,13 @@ namespace brep
     if (x.package != y.package)
       return x.package < y.package;
 
-    if (int r = x.configuration.compare (y.configuration))
+    if (int r = x.target.compare (y.target))
       return r < 0;
 
-    if (int r = x.target.compare (y.target))
+    if (int r = x.target_config_name.compare (y.target_config_name))
+      return r < 0;
+
+    if (int r = x.package_config_name.compare (y.package_config_name))
       return r < 0;
 
     if (int r = x.toolchain_name.compare (y.toolchain_name))
@@ -88,32 +94,36 @@ namespace brep
   template <typename T>
   inline auto
   operator== (const T& x, const build_id& y)
-    -> decltype (x.package == y.package               &&
-                 x.configuration == y.configuration   &&
-                 x.target == y.target                 &&
-                 x.toolchain_name == y.toolchain_name &&
+    -> decltype (x.package == y.package                         &&
+                 x.target == y.target                           &&
+                 x.target_config_name == y.target_config_name   &&
+                 x.package_config_name == y.package_config_name &&
+                 x.toolchain_name == y.toolchain_name           &&
                  x.toolchain_version.epoch == y.toolchain_version.epoch)
   {
-    return x.package == y.package                &&
-           x.configuration == y.configuration    &&
-           x.target == y.target                  &&
-           x.toolchain_name == y.toolchain_name  &&
+    return x.package == y.package                         &&
+           x.target == y.target                           &&
+           x.target_config_name == y.target_config_name   &&
+           x.package_config_name == y.package_config_name &&
+           x.toolchain_name == y.toolchain_name           &&
            compare_version_eq (x.toolchain_version, y.toolchain_version, true);
   }
 
   template <typename T>
   inline auto
   operator!= (const T& x, const build_id& y)
-    -> decltype (x.package == y.package               &&
-                 x.configuration == y.configuration   &&
-                 x.target == y.target                 &&
-                 x.toolchain_name == y.toolchain_name &&
+    -> decltype (x.package == y.package                         &&
+                 x.target == y.target                           &&
+                 x.target_config_name == y.target_config_name   &&
+                 x.package_config_name == y.package_config_name &&
+                 x.toolchain_name == y.toolchain_name           &&
                  x.toolchain_version.epoch == y.toolchain_version.epoch)
   {
-    return x.package != y.package                ||
-           x.configuration != y.configuration    ||
-           x.target == y.target                  ||
-           x.toolchain_name != y.toolchain_name  ||
+    return x.package != y.package                         ||
+           x.target != y.target                           ||
+           x.target_config_name != y.target_config_name   ||
+           x.package_config_name != y.package_config_name ||
+           x.toolchain_name != y.toolchain_name           ||
            compare_version_ne (x.toolchain_version, y.toolchain_version, true);
   }
 
@@ -190,10 +200,10 @@ namespace brep
     // the timestamp set to now, and the force state set to unforced.
     //
     build (string tenant,
-           package_name_type,
-           version,
-           string configuration,
+           package_name_type, version,
            target_triplet,
+           string target_config_name,
+           string package_config_name,
            string toolchain_name, version toolchain_version,
            optional<string> interactive,
            optional<string> agent_fingerprint,
@@ -207,8 +217,9 @@ namespace brep
     string& tenant;                     // Tracks id.package.tenant.
     package_name_type& package_name;    // Tracks id.package.name.
     upstream_version package_version;   // Original of id.package.version.
-    string& configuration;              // Tracks id.configuration.
     target_triplet& target;             // Tracks id.target.
+    string& target_config_name;         // Tracks id.target_config_name.
+    string& package_config_name;        // Tracks id.package_config_name.
     string& toolchain_name;             // Tracks id.toolchain_name.
     upstream_version toolchain_version; // Original of id.toolchain_version.
 
@@ -288,8 +299,9 @@ namespace brep
     #pragma db member(package_name) transient
     #pragma db member(package_version) \
       set(this.package_version.init (this.id.package.version, (?)))
-    #pragma db member(configuration) transient
     #pragma db member(target) transient
+    #pragma db member(target_config_name) transient
+    #pragma db member(package_config_name) transient
     #pragma db member(toolchain_name) transient
     #pragma db member(toolchain_version) \
       set(this.toolchain_version.init (this.id.toolchain_version, (?)))
@@ -312,8 +324,9 @@ namespace brep
     build ()
         : tenant (id.package.tenant),
           package_name (id.package.name),
-          configuration (id.configuration),
           target (id.target),
+          target_config_name (id.target_config_name),
+          package_config_name (id.package_config_name),
           toolchain_name (id.toolchain_name) {}
   };
 
@@ -408,8 +421,9 @@ namespace brep
     //
     build_delay (string tenant,
                  package_name_type, version,
-                 string configuration,
                  target_triplet,
+                 string target_config_name,
+                 string package_config_name,
                  string toolchain_name, version toolchain_version,
                  timestamp package_timestamp);
 
@@ -418,8 +432,9 @@ namespace brep
     string& tenant;                     // Tracks id.package.tenant.
     package_name_type& package_name;    // Tracks id.package.name.
     upstream_version package_version;   // Original of id.package.version.
-    string& configuration;              // Tracks id.configuration.
     target_triplet& target;             // Tracks id.target.
+    string& target_config_name;         // Tracks id.target_config_name.
+    string& package_config_name;        // Tracks id.package_config_name.
     string& toolchain_name;             // Tracks id.toolchain_name.
     upstream_version toolchain_version; // Original of id.toolchain_version.
 
@@ -447,8 +462,9 @@ namespace brep
     #pragma db member(package_name) transient
     #pragma db member(package_version) \
       set(this.package_version.init (this.id.package.version, (?)))
-    #pragma db member(configuration) transient
     #pragma db member(target) transient
+    #pragma db member(target_config_name) transient
+    #pragma db member(package_config_name) transient
     #pragma db member(toolchain_name) transient
     #pragma db member(toolchain_version) \
       set(this.toolchain_version.init (this.id.toolchain_version, (?)))
@@ -459,8 +475,9 @@ namespace brep
     build_delay ()
         : tenant (id.package.tenant),
           package_name (id.package.name),
-          configuration (id.configuration),
           target (id.target),
+          target_config_name (id.target_config_name),
+          package_config_name (id.package_config_name),
           toolchain_name (id.toolchain_name) {}
   };
 }
diff --git a/libbrep/build.xml b/libbrep/build.xml
index 7fe936d..d1969f1 100644
--- a/libbrep/build.xml
+++ b/libbrep/build.xml
@@ -1,5 +1,5 @@
 <changelog xmlns="http://www.codesynthesis.com/xmlns/odb/changelog" database="pgsql" schema-name="build" version="1">
-  <model version="19">
+  <model version="20">
     <table name="build" kind="object">
       <column name="package_tenant" type="TEXT" null="false"/>
       <column name="package_name" type="CITEXT" null="false"/>
@@ -7,8 +7,9 @@
       <column name="package_version_canonical_upstream" type="TEXT" null="false"/>
       <column name="package_version_canonical_release" type="TEXT" null="false" options="COLLATE &quot;C&quot;"/>
       <column name="package_version_revision" type="INTEGER" null="false"/>
-      <column name="configuration" type="TEXT" null="false"/>
       <column name="target" type="TEXT" null="false"/>
+      <column name="target_config_name" type="TEXT" null="false"/>
+      <column name="package_config_name" type="TEXT" null="false"/>
       <column name="toolchain_name" type="TEXT" null="false"/>
       <column name="toolchain_version_epoch" type="INTEGER" null="false"/>
       <column name="toolchain_version_canonical_upstream" type="TEXT" null="false"/>
@@ -41,8 +42,9 @@
         <column name="package_version_canonical_upstream"/>
         <column name="package_version_canonical_release"/>
         <column name="package_version_revision"/>
-        <column name="configuration"/>
         <column name="target"/>
+        <column name="target_config_name"/>
+        <column name="package_config_name"/>
         <column name="toolchain_name"/>
         <column name="toolchain_version_epoch"/>
         <column name="toolchain_version_canonical_upstream"/>
@@ -60,8 +62,9 @@
       <column name="package_version_canonical_upstream" type="TEXT" null="false"/>
       <column name="package_version_canonical_release" type="TEXT" null="false" options="COLLATE &quot;C&quot;"/>
       <column name="package_version_revision" type="INTEGER" null="false"/>
-      <column name="configuration" type="TEXT" null="false"/>
       <column name="target" type="TEXT" null="false"/>
+      <column name="target_config_name" type="TEXT" null="false"/>
+      <column name="package_config_name" type="TEXT" null="false"/>
       <column name="toolchain_name" type="TEXT" null="false"/>
       <column name="toolchain_version_epoch" type="INTEGER" null="false"/>
       <column name="toolchain_version_canonical_upstream" type="TEXT" null="false"/>
@@ -78,8 +81,9 @@
         <column name="package_version_canonical_upstream"/>
         <column name="package_version_canonical_release"/>
         <column name="package_version_revision"/>
-        <column name="configuration"/>
         <column name="target"/>
+        <column name="target_config_name"/>
+        <column name="package_config_name"/>
         <column name="toolchain_name"/>
         <column name="toolchain_version_epoch"/>
         <column name="toolchain_version_canonical_upstream"/>
@@ -92,8 +96,9 @@
           <column name="package_version_canonical_upstream"/>
           <column name="package_version_canonical_release"/>
           <column name="package_version_revision"/>
-          <column name="configuration"/>
           <column name="target"/>
+          <column name="target_config_name"/>
+          <column name="package_config_name"/>
           <column name="toolchain_name"/>
           <column name="toolchain_version_epoch"/>
           <column name="toolchain_version_canonical_upstream"/>
@@ -108,8 +113,9 @@
         <column name="package_version_canonical_upstream"/>
         <column name="package_version_canonical_release"/>
         <column name="package_version_revision"/>
-        <column name="configuration"/>
         <column name="target"/>
+        <column name="target_config_name"/>
+        <column name="package_config_name"/>
         <column name="toolchain_name"/>
         <column name="toolchain_version_epoch"/>
         <column name="toolchain_version_canonical_upstream"/>
@@ -127,8 +133,9 @@
       <column name="package_version_canonical_upstream" type="TEXT" null="false"/>
       <column name="package_version_canonical_release" type="TEXT" null="false" options="COLLATE &quot;C&quot;"/>
       <column name="package_version_revision" type="INTEGER" null="false"/>
-      <column name="configuration" type="TEXT" null="false"/>
       <column name="target" type="TEXT" null="false"/>
+      <column name="target_config_name" type="TEXT" null="false"/>
+      <column name="package_config_name" type="TEXT" null="false"/>
       <column name="toolchain_name" type="TEXT" null="false"/>
       <column name="toolchain_version_epoch" type="INTEGER" null="false"/>
       <column name="toolchain_version_canonical_upstream" type="TEXT" null="false"/>
@@ -148,8 +155,9 @@
         <column name="package_version_canonical_upstream"/>
         <column name="package_version_canonical_release"/>
         <column name="package_version_revision"/>
-        <column name="configuration"/>
         <column name="target"/>
+        <column name="target_config_name"/>
+        <column name="package_config_name"/>
         <column name="toolchain_name"/>
         <column name="toolchain_version_epoch"/>
         <column name="toolchain_version_canonical_upstream"/>
diff --git a/libbrep/common.cxx b/libbrep/common.cxx
index 4f729a3..c97a346 100644
--- a/libbrep/common.cxx
+++ b/libbrep/common.cxx
@@ -32,4 +32,14 @@ namespace brep
     else if (r == "unbuildable") return unbuildable_reason::unbuildable;
     else throw invalid_argument ("invalid unbuildable reason '" + r + '\'');
   }
+
+  build_package_config*
+  find (const string& name, build_package_configs& cs)
+  {
+    auto i (find_if (cs.begin (), cs.end (),
+                     [&name] (const build_package_config& c)
+                     {return c.name == name;}));
+
+    return i != cs.end () ? &*i : nullptr;
+  }
 }
diff --git a/libbrep/common.hxx b/libbrep/common.hxx
index af34f6c..158690e 100644
--- a/libbrep/common.hxx
+++ b/libbrep/common.hxx
@@ -4,6 +4,7 @@
 #ifndef LIBBREP_COMMON_HXX
 #define LIBBREP_COMMON_HXX
 
+#include <map>
 #include <ratio>
 #include <chrono>
 #include <type_traits> // static_assert
@@ -332,6 +333,104 @@ namespace brep
 
   #pragma db value(build_constraint) definition
 
+  // build_package_config
+  //
+  using build_package_config = bpkg::build_package_config;
+
+  #pragma db value(build_package_config) definition
+
+  // 1 for the default configuration which is always present.
+  //
+  using build_package_configs = small_vector<build_package_config, 1>;
+
+  // Return the address of the configuration object with the specified name,
+  // if present, and NULL otherwise.
+  //
+  build_package_config*
+  find (const string& name, build_package_configs&);
+
+  // Note that ODB doesn't support containers of value types which contain
+  // containers. Thus, we will persist/load
+  // package_build_config::{builds,constraint} via the separate nested
+  // containers using the adapter classes.
+  //
+  #pragma db member(build_package_config::builds) transient
+  #pragma db member(build_package_config::constraints) transient
+
+  using build_class_expr_key = odb::nested_key<build_class_exprs>;
+  using build_class_exprs_map = std::map<build_class_expr_key, build_class_expr>;
+
+  #pragma db value(build_class_expr_key)
+  #pragma db member(build_class_expr_key::outer) column("config_index")
+  #pragma db member(build_class_expr_key::inner) column("index")
+
+  // Adapter for build_package_config::builds.
+  //
+  class build_package_config_builds:
+    public small_vector<build_class_exprs, 1> // 1 as for build_package_configs.
+  {
+  public:
+    build_package_config_builds () = default;
+
+    explicit
+    build_package_config_builds (const build_package_configs& cs)
+    {
+      reserve (cs.size ());
+      for (const build_package_config& c: cs)
+        push_back (c.builds);
+    }
+
+    void
+    to_configs (build_package_configs& cs) &&
+    {
+      // Note that the empty trailing entries will be missing (see ODB's
+      // nested-container.hxx for details).
+      //
+      assert (size () <= cs.size ());
+
+      auto i (cs.begin ());
+      for (build_class_exprs& ces: *this)
+        i++->builds = move (ces);
+    }
+  };
+
+  using build_constraint_key = odb::nested_key<build_constraints>;
+  using build_constraints_map = std::map<build_constraint_key, build_constraint>;
+
+  #pragma db value(build_constraint_key)
+  #pragma db member(build_constraint_key::outer) column("config_index")
+  #pragma db member(build_constraint_key::inner) column("index")
+
+  // Adapter for build_package_config::constraints.
+  //
+  class build_package_config_constraints:
+    public small_vector<build_constraints, 1> // 1 as for build_package_configs.
+  {
+  public:
+    build_package_config_constraints () = default;
+
+    explicit
+    build_package_config_constraints (const build_package_configs& cs)
+    {
+      reserve (cs.size ());
+      for (const build_package_config& c: cs)
+        push_back (c.constraints);
+    }
+
+    void
+    to_configs (build_package_configs& cs) &&
+    {
+      // Note that the empty trailing entries will be missing (see ODB's
+      // nested-container.hxx for details).
+      //
+      assert (size () <= cs.size ());
+
+      auto i (cs.begin ());
+      for (build_constraints& bcs: *this)
+        i++->constraints = move (bcs);
+    }
+  };
+
   // The primary reason why a package is unbuildable by the build bot
   // controller service.
   //
@@ -398,6 +497,8 @@ namespace brep
     std::map<requirement_alternative_key, requirement_alternative>;
 
   #pragma db value(requirement_alternative_key)
+  #pragma db member(requirement_alternative_key::outer) column("requirement_index")
+  #pragma db member(requirement_alternative_key::inner) column("index")
 
   using requirement_key = odb::nested2_key<requirement_alternatives>;
 
@@ -405,6 +506,9 @@ namespace brep
     std::map<requirement_key, string>;
 
   #pragma db value(requirement_key)
+  #pragma db member(requirement_key::outer)  column("requirement_index")
+  #pragma db member(requirement_key::middle) column("alternative_index")
+  #pragma db member(requirement_key::inner)  column("index")
 
   // Version comparison operators.
   //
diff --git a/libbrep/package.cxx b/libbrep/package.cxx
index 5f99fbb..152d1d8 100644
--- a/libbrep/package.cxx
+++ b/libbrep/package.cxx
@@ -77,6 +77,7 @@ namespace brep
            small_vector<test_dependency, 1> ts,
            build_class_exprs bs,
            build_constraints_type bc,
+           build_package_configs bcs,
            optional<path> lc,
            optional<string> fr,
            optional<string> sh,
@@ -114,6 +115,24 @@ namespace brep
         fragment (move (fr)),
         sha256sum (move (sh))
   {
+    // Add the default build configuration at the beginning, unless it is
+    // specified explicitly.
+    //
+    if (find_if (bcs.begin (), bcs.end (),
+                 [] (const build_package_config& c)
+                 {return c.name == "default";}) != bcs.end ())
+    {
+      build_configs = move (bcs);
+    }
+    else
+    {
+      build_configs.reserve (bcs.size () + 1);
+      build_configs.emplace_back ("default");
+      build_configs.insert (build_configs.end (),
+                            make_move_iterator (bcs.begin ()),
+                            make_move_iterator (bcs.end ()));
+    }
+
     if (stub ())
       unbuildable_reason = brep::unbuildable_reason::stub;
     else if (!internal_repository->buildable)
diff --git a/libbrep/package.hxx b/libbrep/package.hxx
index c586d74..4a68a07 100644
--- a/libbrep/package.hxx
+++ b/libbrep/package.hxx
@@ -20,7 +20,7 @@
 //
 #define LIBBREP_PACKAGE_SCHEMA_VERSION_BASE 25
 
-#pragma db model version(LIBBREP_PACKAGE_SCHEMA_VERSION_BASE, 25, closed)
+#pragma db model version(LIBBREP_PACKAGE_SCHEMA_VERSION_BASE, 26, closed)
 
 namespace brep
 {
@@ -417,6 +417,9 @@ namespace brep
 
     // Create internal package object.
     //
+    // Note: adds the default build package config at the first position if it
+    // is not present yet.
+    //
     package (package_name,
              version_type,
              optional<string> upstream_version,
@@ -443,6 +446,7 @@ namespace brep
              small_vector<test_dependency, 1> tests,
              build_class_exprs,
              build_constraints_type,
+             build_package_configs,
              optional<path> location,
              optional<string> fragment,
              optional<string> sha256sum,
@@ -513,8 +517,14 @@ namespace brep
     requirements_type requirements;           // Note: foreign-mapped in build.
     small_vector<test_dependency, 1> tests;   // Note: foreign-mapped in build.
 
+    // Common build classes/constraints that apply to all configurations
+    // unless overridden.
+    //
     build_class_exprs builds;                 // Note: foreign-mapped in build.
     build_constraints_type build_constraints; // Note: foreign-mapped in build.
+
+    build_package_configs build_configs; // Note: foreign-mapped in build.
+
     odb::section build_section;
 
     // Note that it is foreign-mapped in build.
@@ -634,9 +644,6 @@ namespace brep
 
     // Container of the requirement_alternative values.
     //
-    #pragma db member(requirement_alternative_key::outer) column("requirement_index")
-    #pragma db member(requirement_alternative_key::inner) column("index")
-
     #pragma db member(requirement_alternatives)               \
       virtual(requirement_alternatives_map)                   \
       after(requirements)                                     \
@@ -646,10 +653,6 @@ namespace brep
 
     // Container of the requirement (string) values.
     //
-    #pragma db member(requirement_key::outer)  column("requirement_index")
-    #pragma db member(requirement_key::middle) column("alternative_index")
-    #pragma db member(requirement_key::inner)  column("index")
-
     #pragma db member(requirement_alternative_requirements)    \
       virtual(requirement_alternative_requirements_map)        \
       after(requirement_alternatives)                          \
@@ -671,6 +674,37 @@ namespace brep
     #pragma db member(build_constraints) id_column("") value_column("") \
       section(build_section)
 
+    // build_configs
+    //
+    // Note that build_package_config::{builds,constraints} are
+    // persisted/loaded via the separate nested containers (see commons.hxx
+    // for details).
+    //
+    #pragma db member(build_configs) id_column("") value_column("config_") \
+      section(build_section)
+
+    #pragma db member(build_config_builds)                           \
+      virtual(build_class_exprs_map)                                 \
+      after(build_configs)                                           \
+      get(odb::nested_get (                                          \
+            brep::build_package_config_builds (this.build_configs))) \
+      set(brep::build_package_config_builds bs;                      \
+          odb::nested_set (bs, std::move (?));                       \
+          move (bs).to_configs (this.build_configs))                 \
+      id_column("") key_column("") value_column("")                  \
+      section(build_section)
+
+    #pragma db member(build_config_constraints)                           \
+      virtual(build_constraints_map)                                      \
+      after(build_config_builds)                                          \
+      get(odb::nested_get (                                               \
+            brep::build_package_config_constraints (this.build_configs))) \
+      set(brep::build_package_config_constraints cs;                      \
+          odb::nested_set (cs, std::move (?));                            \
+          move (cs).to_configs (this.build_configs))                      \
+      id_column("") key_column("") value_column("")                       \
+      section(build_section)
+
     #pragma db member(build_section) load(lazy) update(always)
 
     // other_repositories
diff --git a/libbrep/package.xml b/libbrep/package.xml
index 2e7a613..4e5544a 100644
--- a/libbrep/package.xml
+++ b/libbrep/package.xml
@@ -1,4 +1,138 @@
 <changelog xmlns="http://www.codesynthesis.com/xmlns/odb/changelog" database="pgsql" schema-name="package" version="1">
+  <changeset version="26">
+    <add-table name="package_build_configs" kind="container">
+      <column name="tenant" type="TEXT" null="false"/>
+      <column name="name" type="CITEXT" null="false"/>
+      <column name="version_epoch" type="INTEGER" null="false"/>
+      <column name="version_canonical_upstream" type="TEXT" null="false"/>
+      <column name="version_canonical_release" type="TEXT" null="false" options="COLLATE &quot;C&quot;"/>
+      <column name="version_revision" type="INTEGER" null="false"/>
+      <column name="index" type="BIGINT" null="false"/>
+      <column name="config_name" type="TEXT" null="false"/>
+      <column name="config_arguments" type="TEXT" null="false"/>
+      <column name="config_comment" type="TEXT" null="false"/>
+      <foreign-key name="tenant_fk" deferrable="DEFERRED">
+        <column name="tenant"/>
+        <references table="tenant">
+          <column name="id"/>
+        </references>
+      </foreign-key>
+      <foreign-key name="object_id_fk" on-delete="CASCADE">
+        <column name="tenant"/>
+        <column name="name"/>
+        <column name="version_epoch"/>
+        <column name="version_canonical_upstream"/>
+        <column name="version_canonical_release"/>
+        <column name="version_revision"/>
+        <references table="package">
+          <column name="tenant"/>
+          <column name="name"/>
+          <column name="version_epoch"/>
+          <column name="version_canonical_upstream"/>
+          <column name="version_canonical_release"/>
+          <column name="version_revision"/>
+        </references>
+      </foreign-key>
+      <index name="package_build_configs_object_id_i">
+        <column name="tenant"/>
+        <column name="name"/>
+        <column name="version_epoch"/>
+        <column name="version_canonical_upstream"/>
+        <column name="version_canonical_release"/>
+        <column name="version_revision"/>
+      </index>
+      <index name="package_build_configs_index_i">
+        <column name="index"/>
+      </index>
+    </add-table>
+    <add-table name="package_build_config_builds" kind="container">
+      <column name="tenant" type="TEXT" null="false"/>
+      <column name="name" type="CITEXT" null="false"/>
+      <column name="version_epoch" type="INTEGER" null="false"/>
+      <column name="version_canonical_upstream" type="TEXT" null="false"/>
+      <column name="version_canonical_release" type="TEXT" null="false" options="COLLATE &quot;C&quot;"/>
+      <column name="version_revision" type="INTEGER" null="false"/>
+      <column name="config_index" type="BIGINT" null="false"/>
+      <column name="index" type="BIGINT" null="false"/>
+      <column name="expression" type="TEXT" null="false"/>
+      <column name="comment" type="TEXT" null="false"/>
+      <foreign-key name="tenant_fk" deferrable="DEFERRED">
+        <column name="tenant"/>
+        <references table="tenant">
+          <column name="id"/>
+        </references>
+      </foreign-key>
+      <foreign-key name="object_id_fk" on-delete="CASCADE">
+        <column name="tenant"/>
+        <column name="name"/>
+        <column name="version_epoch"/>
+        <column name="version_canonical_upstream"/>
+        <column name="version_canonical_release"/>
+        <column name="version_revision"/>
+        <references table="package">
+          <column name="tenant"/>
+          <column name="name"/>
+          <column name="version_epoch"/>
+          <column name="version_canonical_upstream"/>
+          <column name="version_canonical_release"/>
+          <column name="version_revision"/>
+        </references>
+      </foreign-key>
+      <index name="package_build_config_builds_object_id_i">
+        <column name="tenant"/>
+        <column name="name"/>
+        <column name="version_epoch"/>
+        <column name="version_canonical_upstream"/>
+        <column name="version_canonical_release"/>
+        <column name="version_revision"/>
+      </index>
+    </add-table>
+    <add-table name="package_build_config_constraints" kind="container">
+      <column name="tenant" type="TEXT" null="false"/>
+      <column name="name" type="CITEXT" null="false"/>
+      <column name="version_epoch" type="INTEGER" null="false"/>
+      <column name="version_canonical_upstream" type="TEXT" null="false"/>
+      <column name="version_canonical_release" type="TEXT" null="false" options="COLLATE &quot;C&quot;"/>
+      <column name="version_revision" type="INTEGER" null="false"/>
+      <column name="config_index" type="BIGINT" null="false"/>
+      <column name="index" type="BIGINT" null="false"/>
+      <column name="exclusion" type="BOOLEAN" null="false"/>
+      <column name="config" type="TEXT" null="false"/>
+      <column name="target" type="TEXT" null="true"/>
+      <column name="comment" type="TEXT" null="false"/>
+      <foreign-key name="tenant_fk" deferrable="DEFERRED">
+        <column name="tenant"/>
+        <references table="tenant">
+          <column name="id"/>
+        </references>
+      </foreign-key>
+      <foreign-key name="object_id_fk" on-delete="CASCADE">
+        <column name="tenant"/>
+        <column name="name"/>
+        <column name="version_epoch"/>
+        <column name="version_canonical_upstream"/>
+        <column name="version_canonical_release"/>
+        <column name="version_revision"/>
+        <references table="package">
+          <column name="tenant"/>
+          <column name="name"/>
+          <column name="version_epoch"/>
+          <column name="version_canonical_upstream"/>
+          <column name="version_canonical_release"/>
+          <column name="version_revision"/>
+        </references>
+      </foreign-key>
+      <index name="package_build_config_constraints_object_id_i">
+        <column name="tenant"/>
+        <column name="name"/>
+        <column name="version_epoch"/>
+        <column name="version_canonical_upstream"/>
+        <column name="version_canonical_release"/>
+        <column name="version_revision"/>
+      </index>
+    </add-table>
+  </changeset>
+
   <model version="25">
     <table name="tenant" kind="object">
       <column name="id" type="TEXT" null="false"/>
diff --git a/libbrep/utility.hxx b/libbrep/utility.hxx
index 7058c94..fce8fb5 100644
--- a/libbrep/utility.hxx
+++ b/libbrep/utility.hxx
@@ -4,11 +4,12 @@
 #ifndef LIBBREP_UTILITY_HXX
 #define LIBBREP_UTILITY_HXX
 
-#include <memory>   // make_shared()
-#include <string>   // to_string()
-#include <utility>  // move(), forward(), declval(), make_pair()
-#include <cassert>  // assert()
-#include <iterator> // make_move_iterator()
+#include <memory>    // make_shared()
+#include <string>    // to_string()
+#include <utility>   // move(), forward(), declval(), make_pair()
+#include <cassert>   // assert()
+#include <iterator>  // make_move_iterator()
+#include <algorithm> // *
 
 #include <libbutl/utility.hxx> // icasecmp(), reverse_iterate(),
                                // operator<<(ostream, exception)