From ee0456ed4a5f3f6686fbb0a433161d1f9d8535fe Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Thu, 4 Jul 2019 07:30:23 +0200
Subject: Remove libu{} target group

The semantics provided by libu{} is rarely required and as result was not
yet documented. However, if you are using it, the new way to achieve the
same result is to use both libue{} and libul{} explicitly, for example:

exe{foo}: libue{foo}
lib{foo}: libul{foo}

{libue libul}{foo}: cxx{*}
---
 build2/bin/init.cxx   |  5 ++---
 build2/bin/target.cxx | 32 ++++++--------------------------
 build2/bin/target.hxx | 27 ++++++++++++++++++---------
 3 files changed, 26 insertions(+), 38 deletions(-)

(limited to 'build2/bin')

diff --git a/build2/bin/init.cxx b/build2/bin/init.cxx
index 37fad6b..5932b29 100644
--- a/build2/bin/init.cxx
+++ b/build2/bin/init.cxx
@@ -439,7 +439,9 @@ namespace build2
         t.insert<hbmia> ();
         t.insert<hbmis> ();
 
+#if 0
         t.insert<libu>  ();
+#endif
         t.insert<libul> ();
         t.insert<libue> ();
         t.insert<libua> ();
@@ -516,9 +518,6 @@ namespace build2
         r.insert<hbmi> (perform_update_id, "bin.hbmi", fail_);
         r.insert<hbmi> (perform_clean_id,  "bin.hbmi", fail_);
 
-        r.insert<libu> (perform_update_id, "bin.libu", fail_);
-        r.insert<libu> (perform_clean_id,  "bin.libu", fail_);
-
         r.insert<libul> (perform_update_id, "bin.libul", fail_);
         r.insert<libul> (perform_clean_id,  "bin.libul", fail_);
 
diff --git a/build2/bin/target.cxx b/build2/bin/target.cxx
index 46f19bd..7c16506 100644
--- a/build2/bin/target.cxx
+++ b/build2/bin/target.cxx
@@ -215,33 +215,11 @@ namespace build2
       false
     };
 
-    // libu*{} member factory.
-    //
-    template <typename M>
-    static target*
-    libux_factory (const target_type&, dir_path dir, dir_path out, string n)
-    {
-      const target* g (targets.find<libu> (dir, out, n));
-
-      if (const target* g2 = targets.find<libul> (dir, out, n))
-      {
-        if (g != 0)
-          fail << "both " << *g << " and " << *g2 << " targets declared";
-
-        g = g2;
-      }
-
-      M* m (new M (move (dir), move (out), move (n)));
-      m->group = g;
-
-      return m;
-    }
-
     const target_type libue::static_type
     {
       "libue",
       &libux::static_type,
-      &libux_factory<libue>,
+      &target_factory<libue>,
       nullptr, /* fixed_extension */
       &target_extension_var<var_extension, nullptr>,
       &target_pattern_var<var_extension, nullptr>,
@@ -254,7 +232,7 @@ namespace build2
     {
       "libua",
       &libux::static_type,
-      &libux_factory<libua>,
+      &m_factory<libua, libul>,
       nullptr, /* fixed_extension */
       &target_extension_var<var_extension, nullptr>,
       &target_pattern_var<var_extension, nullptr>,
@@ -267,7 +245,7 @@ namespace build2
     {
       "libus",
       &libux::static_type,
-      &libux_factory<libus>,
+      &m_factory<libus, libul>,
       nullptr, /* fixed_extension */
       &target_extension_var<var_extension, nullptr>,
       &target_pattern_var<var_extension, nullptr>,
@@ -375,11 +353,12 @@ namespace build2
       false
     };
 
+#if 0
     const target_type libu::static_type
     {
       "libu",
       &libx::static_type,
-      &g_factory<libu, libue, libua, libus>,
+      &target_factory<libu>,
       nullptr,
       nullptr,
       nullptr,
@@ -387,6 +366,7 @@ namespace build2
       &target_search,
       false
     };
+#endif
 
     // What extensions should we use? At the outset, this is platform-
     // dependent. And if we consider cross-compilation, is it build or
diff --git a/build2/bin/target.hxx b/build2/bin/target.hxx
index a56c636..12065bf 100644
--- a/build2/bin/target.hxx
+++ b/build2/bin/target.hxx
@@ -191,7 +191,7 @@ namespace build2
     };
 
 
-    // Common base for lib{} and libul{}/libu{} groups.
+    // Common base for lib{} and libul{} groups.
     //
     // We use mtime_target as a base for the "trust me it exists" functionality
     // which we use, for example, to have installed lib{} prerequisites that
@@ -206,20 +206,27 @@ namespace build2
       static const target_type static_type;
     };
 
-    // The libul{}/libu{} target groups (utility library).
+    // The libue{} target, libul{} group and libua{} and libus{} members
+    // (utility library).
     //
-    // All the members are static libraries that differ based on the kind of
-    // object files they contains. Note that the group is more like obj{}
-    // rather than lib{} in that one does not build the group directly rather
-    // picking a suitable member.
+    // Utility libraries are static libraries that differ based on the kind of
+    // object files they contains. Note that the libul{} group is more like
+    // obj{} rather than lib{} in that one does not build the group directly
+    // rather picking a suitable member.
     //
     // libul{} is a "library utility library" in that the choice of members is
     // libua{} or libus{}, even when linking an executable (normally a unit
     // test).
     //
-    // libu{} is a general utility library with all three types of members. It
-    // would normally be used when you want to build both a library from
-    // libua{}/libus{} and an executable from libue{}.
+    // Note that there is no "general utility library" with all three types of
+    // members (that would cause member uplink ambiguity). If you need to
+    // build both a library from libua{}/libus{} and an executable from
+    // libue{} then you will need to arrange this explicitly, for example:
+    //
+    // exe{foo}: libue{foo}
+    // lib{foo}: libul{foo}
+    //
+    // {libue libul}{foo}: cxx{*}
     //
     class libux: public file // Common base of all libuX{} static libraries.
     {
@@ -270,6 +277,7 @@ namespace build2
       virtual const target_type& dynamic_type () const {return static_type;}
     };
 
+#if 0
     class libu: public libx
     {
     public:
@@ -279,6 +287,7 @@ namespace build2
       static const target_type static_type;
       virtual const target_type& dynamic_type () const {return static_type;}
     };
+#endif
 
     // The lib{} target group.
     //
-- 
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