ENH: Better policies for functions and macros

This teaches functions and macros to use policies recorded at creation
time when they are invoked.  It restores the policies as a weak policy
stack entry so that any policies set by a function escape to its caller
as before.

7 files changed, 45 insertions, 2 deletions

diff --git a/Source/cmCMakePolicyCommand.h b/Source/cmCMakePolicyCommand.h
index d2315ea..e74a6cf 100644
--- a/Source/cmCMakePolicyCommand.h
+++ b/Source/cmCMakePolicyCommand.h
@@ -123,6 +123,12 @@ public:
       "  cmake_policy(POP)\n"
       "Each PUSH must have a matching POP to erase any changes.  "
       "This is useful to make temporary changes to policy settings."
+      "\n"
+      "Functions and macros record policy settings when they are created "
+      "and use the pre-record policies when they are invoked.  "
+      "If the function or macro implementation sets policies, the changes "
+      "automatically propagate up through callers until they reach the "
+      "closest nested policy stack entry."
       ;
     }
   
diff --git a/Source/cmFunctionCommand.cxx b/Source/cmFunctionCommand.cxx
index 2b5223b..9095961 100644
--- a/Source/cmFunctionCommand.cxx
+++ b/Source/cmFunctionCommand.cxx
@@ -36,6 +36,7 @@ public:
     // we must copy when we clone
     newC->Args = this->Args;
     newC->Functions = this->Functions;
+    newC->Policies = this->Policies;
     return newC;
   }
 
@@ -81,6 +82,7 @@ public:
 
   std::vector<std::string> Args;
   std::vector<cmListFileFunction> Functions;
+  cmPolicies::PolicyMap Policies;
 };
 
 
@@ -108,6 +110,10 @@ bool cmFunctionHelperCommand::InvokeInitialPass
   cmMakefile::ScopePushPop varScope(this->Makefile);
   static_cast<void>(varScope);
 
+  // Push a weak policy scope which restores the policies recorded at
+  // function creation.
+  cmMakefile::PolicyPushPop polScope(this->Makefile, true, this->Policies);
+
   // set the value of argc
   cmOStringStream strStream;
   strStream << expandedArgs.size();
@@ -165,6 +171,7 @@ bool cmFunctionHelperCommand::InvokeInitialPass
       // The error message should have already included the call stack
       // so we do not need to report an error here.
       lexScope.Quiet();
+      polScope.Quiet();
       inStatus.SetNestedError(true);
       return false;
       }
@@ -206,6 +213,7 @@ IsFunctionBlocked(const cmListFileFunction& lff, cmMakefile &mf,
       cmFunctionHelperCommand *f = new cmFunctionHelperCommand();
       f->Args = this->Args;
       f->Functions = this->Functions;
+      mf.RecordPolicies(f->Policies);
       
       // Set the FilePath on the arguments to match the function since it is
       // not stored and the original values may be freed
diff --git a/Source/cmFunctionCommand.h b/Source/cmFunctionCommand.h
index b9f9010..ced8218 100644
--- a/Source/cmFunctionCommand.h
+++ b/Source/cmFunctionCommand.h
@@ -104,7 +104,11 @@ public:
       "will have the actual values of the arguments passed in. This "
       "facilitates creating functions with optional arguments. Additionally "
       "ARGV holds the list of all arguments given to the function and ARGN "
-      "holds the list of argument pass the last expected argument.";
+      "holds the list of argument pass the last expected argument."
+      "\n"
+      "See the cmake_policy() command documentation for the behavior of "
+      "policies inside functions."
+      ;
     }
 
   cmTypeMacro(cmFunctionCommand, cmCommand);
diff --git a/Source/cmMacroCommand.cxx b/Source/cmMacroCommand.cxx
index 9cc2653..c736e09 100644
--- a/Source/cmMacroCommand.cxx
+++ b/Source/cmMacroCommand.cxx
@@ -36,6 +36,7 @@ public:
     // we must copy when we clone
     newC->Args = this->Args;
     newC->Functions = this->Functions;
+    newC->Policies = this->Policies;
     return newC;
   }
 
@@ -81,6 +82,7 @@ public:
 
   std::vector<std::string> Args;
   std::vector<cmListFileFunction> Functions;
+  cmPolicies::PolicyMap Policies;
 };
 
 
@@ -110,6 +112,10 @@ bool cmMacroHelperCommand::InvokeInitialPass
   // Enforce matching logical blocks inside the macro.
   cmMakefile::LexicalPushPop lexScope(this->Makefile);
 
+  // Push a weak policy scope which restores the policies recorded at
+  // macro creation.
+  cmMakefile::PolicyPushPop polScope(this->Makefile, true, this->Policies);
+
   // set the value of argc
   cmOStringStream argcDefStream;
   argcDefStream << expandedArgs.size();
@@ -219,6 +225,7 @@ bool cmMacroHelperCommand::InvokeInitialPass
       // The error message should have already included the call stack
       // so we do not need to report an error here.
       lexScope.Quiet();
+      polScope.Quiet();
       inStatus.SetNestedError(true);
       return false;
       }
@@ -264,6 +271,7 @@ IsFunctionBlocked(const cmListFileFunction& lff, cmMakefile &mf,
       cmMacroHelperCommand *f = new cmMacroHelperCommand();
       f->Args = this->Args;
       f->Functions = this->Functions;
+      mf.RecordPolicies(f->Policies);
       std::string newName = "_" + this->Args[0];
       mf.GetCMakeInstance()->RenameCommand(this->Args[0].c_str(), 
                                            newName.c_str());
diff --git a/Source/cmMacroCommand.h b/Source/cmMacroCommand.h
index 3231d71..55da26e 100644
--- a/Source/cmMacroCommand.h
+++ b/Source/cmMacroCommand.h
@@ -111,7 +111,11 @@ public:
       "are not variables in the usual CMake sense. They are string "
       "replacements much like the c preprocessor would do with a "
       "macro. If you want true CMake variables you should look at "
-      "the function command.";
+      "the function command."
+      "\n"
+      "See the cmake_policy() command documentation for the behavior of "
+      "policies inside macros."
+      ;
     }
 
   cmTypeMacro(cmMacroCommand, cmCommand);
diff --git a/Source/cmMakefile.cxx b/Source/cmMakefile.cxx
index 25d97fa..4442bd3 100644
--- a/Source/cmMakefile.cxx
+++ b/Source/cmMakefile.cxx
@@ -3774,3 +3774,15 @@ cmPolicies *cmMakefile::GetPolicies()
   }
   return this->GetCMakeInstance()->GetPolicies();
 }
+
+//----------------------------------------------------------------------------
+void cmMakefile::RecordPolicies(cmPolicies::PolicyMap& pm)
+{
+  /* Record the setting of every policy.  */
+  typedef cmPolicies::PolicyID PolicyID;
+  for(PolicyID pid = cmPolicies::CMP0000;
+      pid != cmPolicies::CMPCOUNT; pid = PolicyID(pid+1))
+    {
+    pm[pid] = this->GetPolicyStatus(pid);
+    }
+}
diff --git a/Source/cmMakefile.h b/Source/cmMakefile.h
index a5fcec1..1c59313 100644
--- a/Source/cmMakefile.h
+++ b/Source/cmMakefile.h
@@ -343,6 +343,7 @@ public:
   bool SetPolicy(const char *id, cmPolicies::PolicyStatus status);
   cmPolicies::PolicyStatus GetPolicyStatus(cmPolicies::PolicyID id);
   bool SetPolicyVersion(const char *version);
+  void RecordPolicies(cmPolicies::PolicyMap& pm);
   //@}
 
   /** Helper class to push and pop policies automatically.  */