From 0e1f5c435f4f1f99211654c30bf363f7ceed8ef1 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Mon, 15 Dec 2014 13:52:26 +0200
Subject: Fix bug in id-based custom view join of polymorphic objects

See email from Mikhail.Tomilov@infotecs.ru/12-Dec-2014.
---
 odb/common-query.cxx | 33 ++++++++++++++++++++-------------
 odb/common-query.hxx |  3 ++-
 2 files changed, 22 insertions(+), 14 deletions(-)

diff --git a/odb/common-query.cxx b/odb/common-query.cxx
index fea8e67..9c4ed9e 100644
--- a/odb/common-query.cxx
+++ b/odb/common-query.cxx
@@ -51,12 +51,14 @@ struct query_nested_types: object_columns_base, virtual context
   {
     // The same logic as in query_columns.
     //
-    if (m.count ("polymorphic-ref") || inverse (m, key_prefix_))
+    if (inverse (m, key_prefix_))
       return;
 
+    bool poly_ref (m.count ("polymorphic-ref"));
+
     if (composite_wrapper (utype (*id_member (c))))
     {
-      if (ptr_)
+      if (ptr_ || poly_ref)
         object_columns_base::traverse_pointer (m, c);
       else
       {
@@ -467,7 +469,7 @@ generate_inst (semantics::data_member& m, semantics::class_& c)
 
 query_columns::
 query_columns (bool decl, bool ptr, semantics::class_& c)
-    : decl_ (decl), ptr_ (ptr), in_ptr_ (false),
+    : decl_ (decl), ptr_ (ptr), poly_ref_ (false), in_ptr_ (false),
       fq_name_ (class_fq_name (c)),
       resue_abstract_ (abstract (c) && !polymorphic (c)),
       depth_ (0)
@@ -544,7 +546,7 @@ traverse_composite (semantics::data_member* m, semantics::class_& c)
     // Derive from the base in query_columns_base. It contains columns
     // data for the pointer members.
     //
-    if (!ptr_ && has_a (c, test_pointer))
+    if (!ptr_ && !poly_ref_ && has_a (c, test_pointer))
       os << ": " << name << "_base_";
 
     os << "{";
@@ -654,11 +656,6 @@ traverse_column (semantics::data_member& m, string const& column, bool)
 void query_columns::
 traverse_pointer (semantics::data_member& m, semantics::class_& c)
 {
-  // Ignore polymorphic id references.
-  //
-  if (m.count ("polymorphic-ref"))
-    return;
-
   // If this is for the pointer_query_columns and the member is not
   // inverse, then create the normal member corresponding to the id
   // column. This will allow the user to check it for NULL or to
@@ -668,6 +665,13 @@ traverse_pointer (semantics::data_member& m, semantics::class_& c)
   if (inverse (m, key_prefix_))
     return;
 
+  // If we ignore polymorphic references, then a view that uses a custom
+  // join condition based on id will use the id column from the base
+  // table. But the base table hasn't been joined yet. To resolve this
+  // we will generate the id member that points to our column.
+  //
+  poly_ref_ = m.count ("polymorphic-ref");
+
   string name (public_name (m));
 
   semantics::data_member& id (*id_member (c));
@@ -679,9 +683,10 @@ traverse_pointer (semantics::data_member& m, semantics::class_& c)
     // Composite id.
     //
 
-    // For pointer_query_columns generate normal composite mapping.
+    // For pointer_query_columns and poly refs generate normal composite
+    // mapping.
     //
-    if (ptr_)
+    if (ptr_ || poly_ref_)
       object_columns_base::traverse_pointer (m, c);
     else
     {
@@ -730,9 +735,9 @@ traverse_pointer (semantics::data_member& m, semantics::class_& c)
     string type (t.fq_name (hint));
     string col (column_name (m, key_prefix_, default_name_, column_prefix_));
 
-    // For pointer_query_columns generate normal column mapping.
+    // For pointer_query_columns and poly refs generate normal column mapping.
     //
-    if (ptr_)
+    if (ptr_ || poly_ref_)
       column_common (m, type, col);
     else
     {
@@ -769,6 +774,8 @@ traverse_pointer (semantics::data_member& m, semantics::class_& c)
       os << "static " << const_ << name << "_type_ " << name << ";"
          << endl;
   }
+
+  poly_ref_ = false;
 }
 
 // query_columns_bases
diff --git a/odb/common-query.hxx b/odb/common-query.hxx
index e0bad6e..49b6027 100644
--- a/odb/common-query.hxx
+++ b/odb/common-query.hxx
@@ -22,7 +22,7 @@ struct query_utils: virtual context
                       semantics::class_&);   // Traverse for nested structs.
 };
 
-// Generate query tags for pointers in this objects.
+// Generate query tags for pointers in this object.
 //
 struct query_tags: object_columns_base, virtual context
 {
@@ -149,6 +149,7 @@ struct query_columns: object_columns_base, virtual context
 protected:
   bool decl_;
   bool ptr_;
+  bool poly_ref_;
   string const_;   // Const prefix or empty.
   bool in_ptr_;    // True while we are "inside" an object pointer.
   string fq_name_;
-- 
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