Merge topic 'DisableSwitchForFindPackage'

4a50b5f Add a basic test for CMAKE_DISABLE_FIND_PACKAGE_<package>
a66df08 Add documentation for the CMAKE_DISABLE_FIND_PACKAGE_<Name> switch
6e1d3ed Add a switch to disable a find_package() call completely

2 files changed, 36 insertions, 0 deletions

diff --git a/Source/cmDocumentVariables.cxx b/Source/cmDocumentVariables.cxx
index ea25e60..4e75f9c 100644
--- a/Source/cmDocumentVariables.cxx
+++ b/Source/cmDocumentVariables.cxx
@@ -719,6 +719,20 @@ void cmDocumentVariables::DefineVariables(cmake* cm)
      "Variables That Change Behavior");
 
   cm->DefineProperty
+    ("CMAKE_DISABLE_FIND_PACKAGE_<PackageName>", cmProperty::VARIABLE,
+     "Variable for disabling find_package() calls.",
+     "Every non-REQUIRED find_package() call in a project can be disabled "
+     "by setting the variable CMAKE_DISABLE_FIND_PACKAGE_<PackageName> to "
+     "TRUE. This can be used to build a project without an optional package, "
+     "although that package is installed.\n"
+     "This switch should be used during the initial CMake run. Otherwise if "
+     "the package has already been found in a previous CMake run, the "
+     "variables which have been stored in the cache will still be there. "
+     "In the case it is recommended to remove the cache variables for "
+     "this package from the cache using the cache editor or cmake -U", false,
+     "Variables That Change Behavior");
+
+  cm->DefineProperty
     ("CMAKE_USER_MAKE_RULES_OVERRIDE", cmProperty::VARIABLE,
      "Specify a CMake file that overrides platform information.",
      "CMake loads the specified file while enabling support for each "
diff --git a/Source/cmFindPackageCommand.cxx b/Source/cmFindPackageCommand.cxx
index 5f106bc..9d1c220 100644
--- a/Source/cmFindPackageCommand.cxx
+++ b/Source/cmFindPackageCommand.cxx
@@ -335,6 +335,10 @@ void cmFindPackageCommand::GenerateDocumentation()
   this->CommandDocumentation += this->GenericDocumentationPathsOrder;
   this->CommandDocumentation +=
     "\n"
+    "Every non-REQUIRED find_package() call can be disabled by setting the "
+    "variable CMAKE_DISABLE_FIND_PACKAGE_<package> to TRUE. See the "
+    "documentation for the CMAKE_DISABLE_FIND_PACKAGE_<package> variable for "
+    "more information.\n"
     "See the cmake_policy() command documentation for discussion of the "
     "NO_POLICY_SCOPE option."
     ;
@@ -607,6 +611,24 @@ bool cmFindPackageCommand
       }
     }
 
+  std::string disableFindPackageVar = "CMAKE_DISABLE_FIND_PACKAGE_";
+  disableFindPackageVar += this->Name;
+  if(this->Makefile->IsOn(disableFindPackageVar.c_str()))
+    {
+    if (this->Required)
+      {
+      cmOStringStream e;
+      e << "for module " << this->Name << " called with REQUIRED, but "
+        << disableFindPackageVar
+        << " is enabled. A REQUIRED package cannot be disabled.";
+      this->SetError(e.str().c_str());
+      return false;
+      }
+
+    return true;
+    }
+
+
   this->SetModuleVariables(components);
 
   // See if there is a Find<package>.cmake module.