From 327490e698db7a74f6a8e8543e99c6c7c9333a8f Mon Sep 17 00:00:00 2001
From: Brad King <brad.king@kitware.com>
Date: Mon, 29 Jun 2015 14:51:14 -0400
Subject: [PATCH] enable_language: Allow CMakeDetermine<LANG>Compiler module to
 fail early

If the module reports a FATAL_ERROR, skip the rest of the steps to
enable the language to avoid unnecessary following error messages.
---
 Source/cmGlobalGenerator.cxx                                 | 4 ++++
 Tests/RunCMake/Languages/DetermineFail-result.txt            | 1 +
 Tests/RunCMake/Languages/DetermineFail-stderr.txt            | 5 +++++
 Tests/RunCMake/Languages/DetermineFail.cmake                 | 2 ++
 .../Languages/Modules/CMakeDetermineFailCompiler.cmake       | 1 +
 Tests/RunCMake/Languages/RunCMakeTest.cmake                  | 2 ++
 6 files changed, 15 insertions(+)
 create mode 100644 Tests/RunCMake/Languages/DetermineFail-result.txt
 create mode 100644 Tests/RunCMake/Languages/DetermineFail-stderr.txt
 create mode 100644 Tests/RunCMake/Languages/DetermineFail.cmake
 create mode 100644 Tests/RunCMake/Languages/Modules/CMakeDetermineFailCompiler.cmake

diff --git a/Source/cmGlobalGenerator.cxx b/Source/cmGlobalGenerator.cxx
index 14eaeac7a..23ab93de8 100644
--- a/Source/cmGlobalGenerator.cxx
+++ b/Source/cmGlobalGenerator.cxx
@@ -564,6 +564,10 @@ cmGlobalGenerator::EnableLanguage(std::vector<std::string>const& languages,
         cmSystemTools::Error("Could not find cmake module file: ",
                              determineCompiler.c_str());
         }
+      if (cmSystemTools::GetFatalErrorOccured())
+        {
+        return;
+        }
       needTestLanguage[lang] = true;
       // Some generators like visual studio should not use the env variables
       // So the global generator can specify that in this variable
diff --git a/Tests/RunCMake/Languages/DetermineFail-result.txt b/Tests/RunCMake/Languages/DetermineFail-result.txt
new file mode 100644
index 000000000..d00491fd7
--- /dev/null
+++ b/Tests/RunCMake/Languages/DetermineFail-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/Languages/DetermineFail-stderr.txt b/Tests/RunCMake/Languages/DetermineFail-stderr.txt
new file mode 100644
index 000000000..3b4743e15
--- /dev/null
+++ b/Tests/RunCMake/Languages/DetermineFail-stderr.txt
@@ -0,0 +1,5 @@
+^CMake Error at Modules/CMakeDetermineFailCompiler.cmake:[0-9]+ \(message\):
+  This language is not supported.
+Call Stack \(most recent call first\):
+  DetermineFail.cmake:[0-9]+ \(enable_language\)
+  CMakeLists.txt:[0-9]+ \(include\)
diff --git a/Tests/RunCMake/Languages/DetermineFail.cmake b/Tests/RunCMake/Languages/DetermineFail.cmake
new file mode 100644
index 000000000..3c8d17d8f
--- /dev/null
+++ b/Tests/RunCMake/Languages/DetermineFail.cmake
@@ -0,0 +1,2 @@
+list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/Modules)
+enable_language(Fail)
diff --git a/Tests/RunCMake/Languages/Modules/CMakeDetermineFailCompiler.cmake b/Tests/RunCMake/Languages/Modules/CMakeDetermineFailCompiler.cmake
new file mode 100644
index 000000000..3b2d50a34
--- /dev/null
+++ b/Tests/RunCMake/Languages/Modules/CMakeDetermineFailCompiler.cmake
@@ -0,0 +1 @@
+message(FATAL_ERROR "This language is not supported.")
diff --git a/Tests/RunCMake/Languages/RunCMakeTest.cmake b/Tests/RunCMake/Languages/RunCMakeTest.cmake
index 6517a8105..732baae41 100644
--- a/Tests/RunCMake/Languages/RunCMakeTest.cmake
+++ b/Tests/RunCMake/Languages/RunCMakeTest.cmake
@@ -4,3 +4,5 @@ run_cmake(NoLangSHARED)
 run_cmake(LINK_LANGUAGE-genex)
 run_cmake(link-libraries-TARGET_FILE-genex)
 run_cmake(link-libraries-TARGET_FILE-genex-ok)
+
+run_cmake(DetermineFail)