From c6265603e0e98c19f8d81c8edd5a34a550063c02 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Wed, 23 Nov 2016 09:53:18 +0200
Subject: Add support for config.cli=false (leave unconfigured)

---
 build2/cli/init.cxx       | 57 +++++++++++++++++++++++++++++++----------------
 build2/config/utility     |  4 ++--
 build2/config/utility.cxx | 12 ++++++++--
 3 files changed, 50 insertions(+), 23 deletions(-)

(limited to 'build2')

diff --git a/build2/cli/init.cxx b/build2/cli/init.cxx
index 093cdbb..3cb1f98 100644
--- a/build2/cli/init.cxx
+++ b/build2/cli/init.cxx
@@ -28,7 +28,7 @@ namespace build2
     bool
     config_init (scope& rs,
                  scope& bs,
-                 const location&,
+                 const location& l,
                  unique_ptr<module_base>&,
                  bool first,
                  bool optional,
@@ -47,6 +47,9 @@ namespace build2
 
         // Note: some overridable, some not.
         //
+        // The config.cli=false is recognized as an explicit request to leave
+        // the module unconfigured.
+        //
         v.insert<path>    ("config.cli",         true);
         v.insert<strings> ("config.cli.options", true);
 
@@ -59,17 +62,33 @@ namespace build2
       // The plan is as follows: try to configure the module. If this fails,
       // we are using default values, and the module is optional, leave it
       // unconfigured.
-      //
 
-      // We will only honor optional if the user didn't specify any cli
-      // configuration explicitly.
+      // First take care of the explicit request by the user to leave the
+      // module unconfigured.
       //
-      optional = optional && !config::specified (rs, "config.cli");
+      bool conf (true);
 
-      // If the configuration says we are unconfigured, then we don't need to
-      // re-run tests, etc. But we may still need to print the config report.
-      //
-      bool conf (!optional || !config::unconfigured (rs, "config.cli"));
+      if (const path* p = cast_null<path> (rs["config.cli"]))
+      {
+        conf = p->string () != "false";
+
+        if (!conf && !optional)
+          fail (l) << "non-optional module requested to be left unconfigured";
+      }
+
+      if (conf)
+      {
+        // Otherwise we will only honor optional if the user didn't specify
+        // any cli configuration explicitly.
+        //
+        optional = optional && !config::specified (rs, "config.cli");
+
+        // If the configuration says we are unconfigured, then we should't
+        // re-run tests, etc. But we may still need to print the config
+        // report.
+        //
+        conf = !optional || !config::unconfigured (rs, "config.cli");
+      }
 
       if (first)
       {
@@ -168,13 +187,7 @@ namespace build2
             ver = test (cli);
 
             if (ver.empty ())
-            {
-              // Note that we are unconfigured so that we don't keep
-              // re-testing this on each run.
-              //
-              config::unconfigured (rs, "config.cli", true);
               conf = false;
-            }
             else
             {
               auto p (config::required (rs, "config.cli", cli));
@@ -197,6 +210,12 @@ namespace build2
           nv = p.second;
         }
 
+        // Note that we are unconfigured so that we don't keep re-testing this
+        // on each run.
+        //
+        if (!conf)
+          nv = config::unconfigured (rs, "config.cli", true) || nv;
+
         // If this is a new value (e.g., we are configuring), then print the
         // report at verbosity level 2 and up (-v).
         //
@@ -234,7 +253,7 @@ namespace build2
     bool
     init (scope& rs,
           scope& bs,
-          const location& loc,
+          const location& l,
           unique_ptr<module_base>&,
           bool,
           bool optional,
@@ -249,19 +268,19 @@ namespace build2
       // the user load cxx explicitly.
       //
       if (!cast_false<bool> (bs["cxx.loaded"]))
-        fail (loc) << "cxx module must be loaded before cli";
+        fail (l) << "cxx module must be loaded before cli";
 
       // Load cli.config.
       //
       if (!cast_false<bool> (bs["cli.config.loaded"]))
       {
-        if (!load_module ("cli.config", rs, bs, loc, optional, hints))
+        if (!load_module ("cli.config", rs, bs, l, optional, hints))
           return false;
       }
       else if (!cast_false<bool> (bs["cli.config.configured"]))
       {
         if (!optional)
-          fail << "cli module could not be configured" <<
+          fail (l) << "cli module could not be configured" <<
             info << "re-run with -V option for more information";
 
         return false;
diff --git a/build2/config/utility b/build2/config/utility
index de75de4..31270fb 100644
--- a/build2/config/utility
+++ b/build2/config/utility
@@ -120,9 +120,9 @@ namespace build2
 
     // Set the config.*.configured value. Note that you only need to set it to
     // false. It will be automatically ignored if there are any other config.*
-    // values for this module.
+    // values for this module. Return true if this sets a new value.
     //
-    void
+    bool
     unconfigured (scope& root, const string& ns, bool);
 
     // Enter the variable so that it is saved during configuration. See
diff --git a/build2/config/utility.cxx b/build2/config/utility.cxx
index 9131620..4c0e933 100644
--- a/build2/config/utility.cxx
+++ b/build2/config/utility.cxx
@@ -105,7 +105,7 @@ namespace build2
       return l && !cast<bool> (l);
     }
 
-    void
+    bool
     unconfigured (scope& root, const string& ns, bool v)
     {
       // Note: not overridable.
@@ -115,7 +115,15 @@ namespace build2
       if (current_mif->id == configure_id)
         save_variable (root, var);
 
-      root.assign (var) = !v;
+      value& x (root.assign (var));
+
+      if (x.null || cast<bool> (x) != !v)
+      {
+        x = !v;
+        return true;
+      }
+      else
+        return false;
     }
 
     void
-- 
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