Explicitly enable deprecated warnings by default.

Explicitly enable deprecated warnings by default, via the
cmake::GetSuppressDeprecatedWarnings method, which signals
suppression is turned off unless the CMake variables are set
as required.

Add tests and update the documentation for the new
functionality.

3 files changed, 36 insertions, 9 deletions

diff --git a/Source/cmMessageCommand.cxx b/Source/cmMessageCommand.cxx
index fd0345d..8272eb0 100644
--- a/Source/cmMessageCommand.cxx
+++ b/Source/cmMessageCommand.cxx
@@ -66,13 +66,17 @@ bool cmMessageCommand
       fatal = true;
       type = cmake::DEPRECATION_ERROR;
       }
-    else if (this->Makefile->IsOn("CMAKE_WARN_DEPRECATED"))
-      {
-      type = cmake::DEPRECATION_WARNING;
-      }
     else
       {
-      return true;
+      if (this->Makefile->GetCMakeInstance()->GetSuppressDeprecatedWarnings(
+          this->Makefile))
+        {
+        return true;
+        }
+      else
+        {
+        type = cmake::DEPRECATION_WARNING;
+        }
       }
     ++i;
     }
diff --git a/Source/cmake.cxx b/Source/cmake.cxx
index 6481c78..c0a1196 100644
--- a/Source/cmake.cxx
+++ b/Source/cmake.cxx
@@ -2581,10 +2581,7 @@ bool cmake::IsMessageTypeVisible(cmake::MessageType t)
     }
   else if (t == cmake::DEPRECATION_WARNING)
     {
-    // if CMAKE_WARN_DEPRECATED is on, show the message, otherwise suppress it
-    const char* warnDeprecated = this->State->GetInitializedCacheValue(
-                                            "CMAKE_WARN_DEPRECATED");
-    if(cmSystemTools::IsOff(warnDeprecated))
+    if (this->GetSuppressDeprecatedWarnings())
       {
       isVisible = false;
       }
@@ -2916,3 +2913,22 @@ bool cmake::GetSuppressDevWarnings(cmMakefile const* mf)
     return cmSystemTools::IsOn(cacheEntryValue);
     }
 }
+
+bool cmake::GetSuppressDeprecatedWarnings(cmMakefile const* mf)
+{
+  /*
+   * The suppression CMake variable may be set in the CMake configuration file
+   * itself, so we have to check what its set to in the makefile if we can.
+   */
+  if (mf)
+    {
+    return (mf->IsSet("CMAKE_WARN_DEPRECATED") &&
+            !mf->IsOn("CMAKE_WARN_DEPRECATED"));
+    }
+  else
+    {
+    const char* cacheEntryValue = this->State->GetCacheEntryValue(
+      "CMAKE_WARN_DEPRECATED");
+    return cacheEntryValue && cmSystemTools::IsOff(cacheEntryValue);
+    }
+}
diff --git a/Source/cmake.h b/Source/cmake.h
index 8739b87..4c5515b 100644
--- a/Source/cmake.h
+++ b/Source/cmake.h
@@ -316,6 +316,13 @@ class cmake
    */
   bool GetSuppressDevWarnings(cmMakefile const* mf = NULL);
 
+  /*
+   * Get the state of the suppression of deprecated warnings.
+   * Returns false, by default, if deprecated warnings should be shown, true
+   * otherwise.
+   */
+  bool GetSuppressDeprecatedWarnings(cmMakefile const* mf = NULL);
+
   /** Display a message to the user.  */
   void IssueMessage(cmake::MessageType t, std::string const& text,
         cmListFileBacktrace const& backtrace = cmListFileBacktrace(),