Adjust conditional dependency declaration warning logic

Now instead of ignoring imported stuff (which turned out to be racy), we only
consider conditions up to the include boundary. The thinking here is that an
included (but not sourced) buildfile is a standalone entity (e.g., imported
project but also could be just a side-included buildfile).

Note that unfortunately we will still be issuing warnings in imported projects
since there is no straightforward way to know what is being distributed and
what is not while parsing.

2 files changed, 19 insertions, 13 deletions

diff --git a/libbuild2/parser.cxx b/libbuild2/parser.cxx
index 84b6366..fd7c10e 100644
--- a/libbuild2/parser.cxx
+++ b/libbuild2/parser.cxx
@@ -247,7 +247,6 @@ namespace build2
   {
     pre_parse_ = false;
     attributes_.clear ();
-    imported_ = false;
     condition_ = nullopt;
     default_target_ = nullptr;
     peeked_ = false;
@@ -2372,9 +2371,7 @@ namespace build2
 
     // Diagnose conditional prerequisites. Note that we want to diagnose this
     // even if pns is empty (think empty variable expansion; the literal "no
-    // prerequisites" case is handled elsewhere). We also want to omit this
-    // check for imported buildfiles (export stub can reasonably wrap loading
-    // of a buildfile in a condition).
+    // prerequisites" case is handled elsewhere).
     //
     // @@ TMP For now we only do it during the dist meta-operation. In the
     //        future we should tighten this to any meta-operation provided
@@ -2385,7 +2382,6 @@ namespace build2
     //        rewrite (cli.cxx{} is not always registered).
     //
     if (condition_ &&
-        !imported_ &&
         ctx->current_mif != nullptr &&
         ctx->current_mif->id == dist_id)
     {
@@ -2918,6 +2914,18 @@ namespace build2
         continue;
       }
 
+      // Clear/restore if/switch location.
+      //
+      // We do it here but not in parse_source since the included buildfile is
+      // in a sense expected to be a standalone entity (think a file included
+      // from an export stub).
+      //
+      auto g = make_guard ([this, old = condition_] () mutable
+                           {
+                             condition_ = old;
+                           });
+      condition_ = nullopt;
+
       try
       {
         ifdstream ifs (p);
diff --git a/libbuild2/parser.hxx b/libbuild2/parser.hxx
index 61ecd5b..5f762f7 100644
--- a/libbuild2/parser.hxx
+++ b/libbuild2/parser.hxx
@@ -91,12 +91,6 @@ namespace build2
     parse_export_stub (istream& is, const path_name& name,
                        scope& rs, scope& bs)
     {
-      auto g = make_guard ([this, old = imported_] () mutable
-                           {
-                             imported_ = old;
-                           });
-      imported_ = true;
-
       parse_buildfile (is, name, &rs, bs);
       return move (export_value);
     }
@@ -912,8 +906,12 @@ namespace build2
 
     small_vector<attributes, 2> attributes_;
 
-    bool imported_ = false;        // True if loaded via export stub.
-    optional<location> condition_; // Innermost if/switch (but not in recipe).
+    // Innermost if/switch (but excluding recipes).
+    //
+    // Note also that this is cleared/restored when crossing the include
+    // (but not source) boundary.
+    //
+    optional<location> condition_;
 
     target* default_target_ = nullptr;