Use install::alisa_rule to ignore non-installable prerequisites

5 files changed, 66 insertions, 9 deletions

diff --git a/build/cxx/install b/build/cxx/install
index 3a6f463..7117fb8 100644
--- a/build/cxx/install
+++ b/build/cxx/install
@@ -12,7 +12,7 @@ namespace build
 {
   namespace cxx
   {
-    class install: public build::install::rule
+    class install: public build::install::file_rule
     {
     public:
       virtual bool
diff --git a/build/cxx/install.cxx b/build/cxx/install.cxx
index b623349..e6417a6 100644
--- a/build/cxx/install.cxx
+++ b/build/cxx/install.cxx
@@ -40,7 +40,7 @@ namespace build
       //
       match_result r (link::instance.match (a, t, hint));
 
-      return r ? install::rule::match (a, t, "") : r;
+      return r ? install::file_rule::match (a, t, "") : r;
     }
 
     install install::instance;
diff --git a/build/install/module.cxx b/build/install/module.cxx
index b117e98..042bee9 100644
--- a/build/install/module.cxx
+++ b/build/install/module.cxx
@@ -89,7 +89,8 @@ namespace build
       set_var<strings> (s, r, name, ".options", nullptr);
     }
 
-    static rule rule_;
+    static alias_rule alias_rule_;
+    static file_rule file_rule_;
 
     extern "C" void
     install_init (scope& r,
@@ -116,9 +117,10 @@ namespace build
       //
       r.operations.insert (install_id, install);
 
-      // Register our file installer rule.
+      // Register our alias and file installer rule.
       //
-      b.rules.insert<file> (perform_id, install_id, "install", rule_);
+      b.rules.insert<alias> (perform_id, install_id, "install", alias_rule_);
+      b.rules.insert<file> (perform_id, install_id, "install", file_rule_);
 
       // Enter module variables.
       //
diff --git a/build/install/rule b/build/install/rule
index bed0836..af38587 100644
--- a/build/install/rule
+++ b/build/install/rule
@@ -14,7 +14,17 @@ namespace build
 {
   namespace install
   {
-    class rule: public build::rule
+    class alias_rule: public rule
+    {
+    public:
+      virtual match_result
+      match (action, target&, const std::string&) const;
+
+      virtual recipe
+      apply (action, target&, const match_result&) const;
+    };
+
+    class file_rule: public rule
     {
     public:
       virtual bool
diff --git a/build/install/rule.cxx b/build/install/rule.cxx
index 64df3eb..6f0f95f 100644
--- a/build/install/rule.cxx
+++ b/build/install/rule.cxx
@@ -38,7 +38,52 @@ namespace build
       return r.simple () && r.string () == "false" ? nullptr : &r;
     }
 
-    match_result rule::
+    // alias_rule
+    //
+    match_result alias_rule::
+    match (action, target& t, const std::string&) const
+    {
+      return t;
+    }
+
+    recipe alias_rule::
+    apply (action a, target& t, const match_result&) const
+    {
+      tracer trace ("install::alias_rule::apply");
+
+      for (prerequisite p: group_prerequisites (t))
+      {
+        target& pt (search (p));
+
+        // Check if this prerequisite is explicitly "not installable",
+        // that is, there is the 'install' variable and its value is
+        // false.
+        //
+        // At first, this might seem redundand since we could have let
+        // the file_rule below take care of it. The nuance is this: this
+        // prerequsite can be in a different subproject that hasn't loaded
+        // the install module (and therefore has no file_rule registered).
+        // The typical example would be the 'tests' subproject.
+        //
+        auto l (pt["install"]);
+
+        if (l && as<dir_path> (*l).string () == "false")
+        {
+          level5 ([&]{trace << "ignoring " << pt;});
+          continue;
+        }
+
+        build::match (a, pt);
+        t.prerequisite_targets.push_back (&pt);
+      }
+
+      return default_recipe;
+    }
+
+    // file_rule
+    //
+
+    match_result file_rule::
     match (action a, target& t, const std::string&) const
     {
       // First determine if this target should be installed (called
@@ -55,7 +100,7 @@ namespace build
       return mr;
     }
 
-    recipe rule::
+    recipe file_rule::
     apply (action a, target& t, const match_result& mr) const
     {
       if (!mr.bvalue) // Not installable.
@@ -304,7 +349,7 @@ namespace build
       return r;
     }
 
-    target_state rule::
+    target_state file_rule::
     perform_install (action a, target& t)
     {
       file& ft (static_cast<file&> (t));