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.

Help/release/dev/cmake-W-options.rst

@@ -6,3 +6,7 @@ cmake-W-options
 
 * The ``-Wdev`` and ``-Wno-dev`` :manual:`cmake(1)` options now also enable
   and suppress the deprecated warnings output by default.
+
+* Warnings about deprecated functionality are now enabled by default.
+  They may be suppressed with ``-Wno-deprecated`` or by setting the
+  :variable:`CMAKE_WARN_DEPRECATED` variable to false.

Help/variable/CMAKE_WARN_DEPRECATED.rst

@@ -3,8 +3,8 @@ CMAKE_WARN_DEPRECATED
 
 Whether to issue warnings for deprecated functionality.
 
-If ``TRUE``, use of deprecated functionality will issue warnings.
-If this variable is not set, CMake behaves as if it were set to ``FALSE``.
+If not ``FALSE``, use of deprecated functionality will issue warnings.
+If this variable is not set, CMake behaves as if it were set to ``TRUE``.
 
 When running :manual:`cmake(1)`, this option can be enabled with the
 ``-Wdeprecated`` option, or disabled with the ``-Wno-deprecated`` option.

Source/cmMessageCommand.cxx

@@ -66,13 +66,17 @@ bool cmMessageCommand
       fatal = true;
       type = cmake::DEPRECATION_ERROR;
       }
-    else if (this->Makefile->IsOn("CMAKE_WARN_DEPRECATED"))
+    else
       {
-      type = cmake::DEPRECATION_WARNING;
+      if (this->Makefile->GetCMakeInstance()->GetSuppressDeprecatedWarnings(
+          this->Makefile))
+        {
+        return true;
         }
       else
         {
-      return true;
+        type = cmake::DEPRECATION_WARNING;
+        }
       }
     ++i;
     }

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);
+    }
+}

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(),

Tests/RunCMake/CommandLine/RunCMakeTest.cmake

@@ -157,6 +157,9 @@ unset(RunCMake_TEST_OPTIONS)
 # Dev warnings should be on by default
 run_cmake(Wdev)
 
+# Deprecated warnings should be on by default
+run_cmake(Wdeprecated)
+
 # Conflicting -W options should honor the last value
 set(RunCMake_TEST_OPTIONS -Wno-dev -Wdev)
 run_cmake(Wdev)

Tests/RunCMake/message/defaultmessage-stderr.txt

@@ -1,4 +1,10 @@
-^CMake Warning \(dev\) at defaultmessage.cmake:4 \(message\):
+^CMake Deprecation Warning at defaultmessage.cmake:2 \(message\):
+  This is a deprecation warning
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)
+
+
+CMake Warning \(dev\) at defaultmessage.cmake:4 \(message\):
   This is a author warning
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)

Tests/RunCMake/message/nomessage.cmake

@@ -1,4 +1,6 @@
 
+set(CMAKE_WARN_DEPRECATED OFF)
+
 message(DEPRECATION "This is not issued")
 
 set(CMAKE_SUPPRESS_DEVELOPER_WARNINGS ON)