cmTarget: Evaluate CMP0026 in calling context

This policy should be checked at the call site that tries to access the
LOCATION property, not the directory scope containing the target.
Thread the caller context through cmTarget::GetProperty to use for
checking the policy setting and emitting a diagnostic with proper
backtrace.

Extend the RunCMake.CMP0026 test with a cross-directory case.

Source/cmGetPropertyCommand.cxx

@@ -302,7 +302,8 @@ bool cmGetPropertyCommand::HandleTargetMode()
     }
   if(cmTarget* target = this->Makefile->FindTargetToUse(this->Name))
     {
-    return this->StoreResult(target->GetProperty(this->PropertyName.c_str()));
+    return this->StoreResult(target->GetProperty(this->PropertyName.c_str(),
+                                                 this->Makefile));
     }
   else
     {

Source/cmGetTargetPropertyCommand.cxx

@@ -38,7 +38,7 @@ bool cmGetTargetPropertyCommand
   else if(cmTarget* tgt = this->Makefile->FindTargetToUse(targetName))
     {
     cmTarget& target = *tgt;
-    prop = target.GetProperty(args[2].c_str());
+    prop = target.GetProperty(args[2].c_str(), this->Makefile);
     }
   else
     {

Source/cmTarget.cxx

@@ -2624,7 +2624,7 @@ const char* cmTarget::GetFeature(const char* feature, const char* config) const
 }
 
 //----------------------------------------------------------------------------
-bool cmTarget::HandleLocationPropertyPolicy() const
+bool cmTarget::HandleLocationPropertyPolicy(cmMakefile* context) const
 {
   if (this->IsImported())
     {
@@ -2633,7 +2633,7 @@ bool cmTarget::HandleLocationPropertyPolicy() const
   cmOStringStream e;
   const char *modal = 0;
   cmake::MessageType messageType = cmake::AUTHOR_WARNING;
-  switch (this->Makefile->GetPolicyStatus(cmPolicies::CMP0026))
+  switch (context->GetPolicyStatus(cmPolicies::CMP0026))
     {
     case cmPolicies::WARN:
       e << (this->Makefile->GetPolicies()
@@ -2654,7 +2654,7 @@ bool cmTarget::HandleLocationPropertyPolicy() const
       << this->GetName() << "\".  Use the target name directly with "
       "add_custom_command, or use the generator expression $<TARGET_FILE>, "
       "as appropriate.\n";
-    this->Makefile->IssueMessage(messageType, e.str().c_str());
+    context->IssueMessage(messageType, e.str().c_str());
     }
 
   return messageType != cmake::FATAL_ERROR;
@@ -2662,6 +2662,13 @@ bool cmTarget::HandleLocationPropertyPolicy() const
 
 //----------------------------------------------------------------------------
 const char *cmTarget::GetProperty(const char* prop) const
+{
+  return this->GetProperty(prop, this->Makefile);
+}
+
+//----------------------------------------------------------------------------
+const char *cmTarget::GetProperty(const char* prop,
+                                  cmMakefile* context) const
 {
   if(!prop)
     {
@@ -2674,7 +2681,7 @@ const char *cmTarget::GetProperty(const char* prop) const
     cmOStringStream e;
     e << "INTERFACE_LIBRARY targets may only have whitelisted properties.  "
          "The property \"" << prop << "\" is not allowed.";
-    this->Makefile->IssueMessage(cmake::FATAL_ERROR, e.str().c_str());
+    context->IssueMessage(cmake::FATAL_ERROR, e.str().c_str());
     return 0;
     }
 
@@ -2693,7 +2700,7 @@ const char *cmTarget::GetProperty(const char* prop) const
     {
     if(strcmp(prop,"LOCATION") == 0)
       {
-      if (!this->HandleLocationPropertyPolicy())
+      if (!this->HandleLocationPropertyPolicy(context))
         {
         return 0;
         }
@@ -2714,7 +2721,7 @@ const char *cmTarget::GetProperty(const char* prop) const
     // Support "LOCATION_<CONFIG>".
     if(cmHasLiteralPrefix(prop, "LOCATION_"))
       {
-      if (!this->HandleLocationPropertyPolicy())
+      if (!this->HandleLocationPropertyPolicy(context))
         {
         return 0;
         }
@@ -2729,7 +2736,7 @@ const char *cmTarget::GetProperty(const char* prop) const
       std::string configName(prop, strlen(prop) - 9);
       if(configName != "IMPORTED")
         {
-        if (!this->HandleLocationPropertyPolicy())
+        if (!this->HandleLocationPropertyPolicy(context))
           {
           return 0;
           }

Source/cmTarget.h

@@ -257,6 +257,7 @@ public:
   void SetProperty(const char *prop, const char *value);
   void AppendProperty(const char* prop, const char* value,bool asString=false);
   const char *GetProperty(const char *prop) const;
+  const char *GetProperty(const char *prop, cmMakefile* context) const;
   bool GetPropertyAsBool(const char *prop) const;
   void CheckProperty(const char* prop, cmMakefile* context) const;
 
@@ -579,7 +580,7 @@ public:
                             const std::string &compatibilityType) const;
 
 private:
-  bool HandleLocationPropertyPolicy() const;
+  bool HandleLocationPropertyPolicy(cmMakefile* context) const;
 
   // The set of include directories that are marked as system include
   // directories.

Tests/RunCMake/CMP0026/CMP0026-WARN-Dir/CMakeLists.txt

@@ -0,0 +1 @@
+add_library(otherlib ../empty.cpp)

Tests/RunCMake/CMP0026/CMP0026-WARN-stderr.txt

@@ -10,3 +10,16 @@ CMake Warning \(dev\) at CMP0026-WARN.cmake:5 \(get_target_property\):
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
 This warning is for project developers.  Use -Wno-dev to suppress it.
++
+CMake Warning \(dev\) at CMP0026-WARN.cmake:8 \(get_target_property\):
+  Policy CMP0026 is not set: Disallow use of the LOCATION target property.
+  Run "cmake --help-policy CMP0026" for policy details.  Use the cmake_policy
+  command to set the policy and suppress this warning.
+
+  The LOCATION property should not be read from target "otherlib".  Use the
+  target name directly with add_custom_command, or use the generator
+  expression \$<TARGET_FILE>, as appropriate.
+
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)
+This warning is for project developers.  Use -Wno-dev to suppress it.

Tests/RunCMake/CMP0026/CMP0026-WARN.cmake

@@ -3,3 +3,6 @@ enable_language(CXX)
 
 add_library(somelib empty.cpp)
 get_target_property(_loc somelib LOCATION)
+
+add_subdirectory(CMP0026-WARN-Dir)
+get_target_property(_loc otherlib LOCATION)