Merge topic 'export-policy'

904ff9f export: Add policy CMP0024 to disallow include() of export files

Source/cmExportCommand.cxx

@@ -171,6 +171,8 @@ bool cmExportCommand
   ebfg.SetCommand(this);
   ebfg.SetExportOld(this->ExportOld.IsEnabled());
 
+  this->Makefile->AddExportedTargetsFile(fname);
+
   // Compute the set of configurations exported.
   std::vector<std::string> configurationTypes;
   this->Makefile->GetConfigurations(configurationTypes);

Source/cmIncludeCommand.cxx

@@ -88,6 +88,45 @@ bool cmIncludeCommand
       fname = mfile.c_str();
       }
     }
+
+  std::string fname_abs =
+      cmSystemTools::CollapseFullPath(fname.c_str(),
+                                      this->Makefile->GetStartDirectory());
+
+  if (this->Makefile->IsExportedTargetsFile(fname_abs))
+    {
+    const char *modal = 0;
+    cmake::MessageType messageType = cmake::AUTHOR_WARNING;
+
+    switch(this->Makefile->GetPolicyStatus(cmPolicies::CMP0024))
+      {
+      case cmPolicies::WARN:
+        modal = "should";
+      case cmPolicies::OLD:
+        break;
+      case cmPolicies::REQUIRED_IF_USED:
+      case cmPolicies::REQUIRED_ALWAYS:
+      case cmPolicies::NEW:
+        modal = "may";
+        messageType = cmake::FATAL_ERROR;
+      }
+    if (modal)
+      {
+      cmOStringStream e;
+      e << (this->Makefile->GetPolicies()
+            ->GetPolicyWarning(cmPolicies::CMP0024)) << "\n";
+      e << "The file\n  " << fname_abs << "\nwas generated by the export() "
+        "command.  It " << modal << " not be used as the argument to the "
+        "include() command.  Use ALIAS targets instead to refer to targets "
+        "by alternative names.\n";
+      this->Makefile->IssueMessage(messageType, e.str().c_str());
+      if (messageType == cmake::FATAL_ERROR)
+        {
+        return false;
+        }
+      }
+    }
+
   std::string fullFilePath;
   bool readit =
     this->Makefile->ReadListFile( this->Makefile->GetCurrentListFile(),

Source/cmMakefile.h

@@ -489,6 +489,18 @@ public:
       return this->cmCurrentListFile.c_str();
     }
 
+  void AddExportedTargetsFile(const std::string &filename)
+  {
+    this->ExportedTargetsFiles.insert(filename);
+  }
+
+  bool IsExportedTargetsFile(const std::string &filename) const
+  {
+    const std::set<std::string>::const_iterator it
+                                  = this->ExportedTargetsFiles.find(filename);
+    return it != this->ExportedTargetsFiles.end();
+  }
+
   //@}
 
   /**
@@ -1041,7 +1053,7 @@ private:
   void EnforceDirectoryLevelRules();
 
   bool GeneratingBuildSystem;
-
+  std::set<std::string> ExportedTargetsFiles;
   /**
    * Old version of GetSourceFileWithOutput(const char*) kept for
    * backward-compatibility. It implements a linear search and support

Source/cmPolicies.cxx

@@ -601,6 +601,25 @@ cmPolicies::cmPolicies()
     "The NEW behavior for this policy is to not to allow mixing of the "
     "keyword and plain signatures.",
     2,8,12,0, cmPolicies::WARN);
+
+  this->DefinePolicy(
+    CMP0024, "CMP0024",
+    "Disallow include export result.",
+    "CMake 2.8.12 and lower allowed use of the include() command with the "
+    "result of the export() command.  This relies on the assumption that "
+    "the export() command has an immediate effect at configure-time during a "
+    "cmake run.  Certain properties of targets are not fully determined "
+    "until later at generate-time, such as the link language and complete "
+    "list of link libraries.  Future refactoring will change the effect of "
+    "the export() command to be executed at generate-time.  Use ALIAS "
+    "targets instead in cases where the goal is to refer to targets by "
+    "another name"
+    "\n"
+    "The OLD behavior for this policy is to allow including the result "
+    "of an export() command.  "
+    "The NEW behavior for this policy is to not to allow including the "
+    "result of an export() command.",
+    2,8,13,0, cmPolicies::WARN);
 }
 
 cmPolicies::~cmPolicies()

Source/cmPolicies.h

@@ -74,6 +74,7 @@ public:
     /// target property
     CMP0022, ///< INTERFACE_LINK_LIBRARIES defines the link interface
     CMP0023, ///< Disallow mixing keyword and plain tll signatures
+    CMP0024, ///< Disallow including export() result.
 
     /** \brief Always the last entry.
      *