From 869904271ba0e8b855043894360b5dc7fe1e3b56 Mon Sep 17 00:00:00 2001
From: Brad King <brad.king@kitware.com>
Date: Mon, 26 Jun 2017 13:48:21 -0400
Subject: [PATCH 1/2] Tests: Enable languages explicitly in
 RunCMake.target_compile_features

Enable C or CXX (or nothing) as needed in each test case.
This will allow us to add test cases that do not enable CXX.
---
 Tests/RunCMake/target_compile_features/CMakeLists.txt           | 2 +-
 Tests/RunCMake/target_compile_features/alias_target-stderr.txt  | 2 +-
 Tests/RunCMake/target_compile_features/alias_target.cmake       | 1 +
 .../RunCMake/target_compile_features/imported_target-stderr.txt | 2 +-
 Tests/RunCMake/target_compile_features/imported_target.cmake    | 1 +
 Tests/RunCMake/target_compile_features/invalid_args-stderr.txt  | 2 +-
 Tests/RunCMake/target_compile_features/invalid_args.cmake       | 1 +
 .../invalid_args_on_interface-stderr.txt                        | 2 +-
 .../target_compile_features/invalid_args_on_interface.cmake     | 1 +
 .../target_compile_features/no_matching_c_feature-stderr.txt    | 2 +-
 .../target_compile_features/no_matching_c_feature.cmake         | 1 +
 .../target_compile_features/no_matching_cxx_feature-stderr.txt  | 2 +-
 .../target_compile_features/no_matching_cxx_feature.cmake       | 1 +
 Tests/RunCMake/target_compile_features/no_target-stderr.txt     | 2 +-
 Tests/RunCMake/target_compile_features/no_target.cmake          | 1 +
 .../RunCMake/target_compile_features/not_a_c_feature-stderr.txt | 2 +-
 Tests/RunCMake/target_compile_features/not_a_c_feature.cmake    | 1 +
 .../target_compile_features/not_a_cxx_feature-stderr.txt        | 2 +-
 Tests/RunCMake/target_compile_features/not_a_cxx_feature.cmake  | 1 +
 .../RunCMake/target_compile_features/not_enough_args-stderr.txt | 2 +-
 Tests/RunCMake/target_compile_features/not_enough_args.cmake    | 1 +
 .../RunCMake/target_compile_features/utility_target-stderr.txt  | 2 +-
 22 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/Tests/RunCMake/target_compile_features/CMakeLists.txt b/Tests/RunCMake/target_compile_features/CMakeLists.txt
index 3482e6baf2..2897109554 100644
--- a/Tests/RunCMake/target_compile_features/CMakeLists.txt
+++ b/Tests/RunCMake/target_compile_features/CMakeLists.txt
@@ -1,3 +1,3 @@
 cmake_minimum_required(VERSION 3.0)
-project(${RunCMake_TEST} CXX)
+project(${RunCMake_TEST} NONE)
 include(${RunCMake_TEST}.cmake)
diff --git a/Tests/RunCMake/target_compile_features/alias_target-stderr.txt b/Tests/RunCMake/target_compile_features/alias_target-stderr.txt
index 417bf62aae..5ebe170c36 100644
--- a/Tests/RunCMake/target_compile_features/alias_target-stderr.txt
+++ b/Tests/RunCMake/target_compile_features/alias_target-stderr.txt
@@ -1,4 +1,4 @@
-CMake Error at alias_target.cmake:4 \(target_compile_features\):
+CMake Error at alias_target.cmake:[0-9]+ \(target_compile_features\):
   target_compile_features can not be used on an ALIAS target.
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
diff --git a/Tests/RunCMake/target_compile_features/alias_target.cmake b/Tests/RunCMake/target_compile_features/alias_target.cmake
index d35ddba541..6fcdadaa59 100644
--- a/Tests/RunCMake/target_compile_features/alias_target.cmake
+++ b/Tests/RunCMake/target_compile_features/alias_target.cmake
@@ -1,3 +1,4 @@
+enable_language(CXX)
 
 add_executable(main empty.cpp)
 add_executable(Alias::Main ALIAS main)
diff --git a/Tests/RunCMake/target_compile_features/imported_target-stderr.txt b/Tests/RunCMake/target_compile_features/imported_target-stderr.txt
index c6ff5ec216..7a07427a00 100644
--- a/Tests/RunCMake/target_compile_features/imported_target-stderr.txt
+++ b/Tests/RunCMake/target_compile_features/imported_target-stderr.txt
@@ -1,4 +1,4 @@
-CMake Error at imported_target.cmake:3 \(target_compile_features\):
+CMake Error at imported_target.cmake:[0-9]+ \(target_compile_features\):
   Cannot specify compile features for imported target "main".
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
diff --git a/Tests/RunCMake/target_compile_features/imported_target.cmake b/Tests/RunCMake/target_compile_features/imported_target.cmake
index e248c2feea..e886ce9224 100644
--- a/Tests/RunCMake/target_compile_features/imported_target.cmake
+++ b/Tests/RunCMake/target_compile_features/imported_target.cmake
@@ -1,3 +1,4 @@
+enable_language(CXX)
 
 add_library(main INTERFACE IMPORTED)
 target_compile_features(main INTERFACE cxx_delegating_constructors)
diff --git a/Tests/RunCMake/target_compile_features/invalid_args-stderr.txt b/Tests/RunCMake/target_compile_features/invalid_args-stderr.txt
index bd5b7b9d54..9917be77a1 100644
--- a/Tests/RunCMake/target_compile_features/invalid_args-stderr.txt
+++ b/Tests/RunCMake/target_compile_features/invalid_args-stderr.txt
@@ -1,4 +1,4 @@
-CMake Error at invalid_args.cmake:3 \(target_compile_features\):
+CMake Error at invalid_args.cmake:[0-9]+ \(target_compile_features\):
   target_compile_features called with invalid arguments
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
diff --git a/Tests/RunCMake/target_compile_features/invalid_args.cmake b/Tests/RunCMake/target_compile_features/invalid_args.cmake
index 1a7fb3749a..cc051a445d 100644
--- a/Tests/RunCMake/target_compile_features/invalid_args.cmake
+++ b/Tests/RunCMake/target_compile_features/invalid_args.cmake
@@ -1,3 +1,4 @@
+enable_language(CXX)
 
 add_executable(main empty.cpp)
 target_compile_features(main INVALID cxx_delegating_constructors)
diff --git a/Tests/RunCMake/target_compile_features/invalid_args_on_interface-stderr.txt b/Tests/RunCMake/target_compile_features/invalid_args_on_interface-stderr.txt
index c30209a28b..37089983a3 100644
--- a/Tests/RunCMake/target_compile_features/invalid_args_on_interface-stderr.txt
+++ b/Tests/RunCMake/target_compile_features/invalid_args_on_interface-stderr.txt
@@ -1,4 +1,4 @@
-CMake Error at invalid_args_on_interface.cmake:3 \(target_compile_features\):
+CMake Error at invalid_args_on_interface.cmake:[0-9]+ \(target_compile_features\):
   target_compile_features may only be set INTERFACE properties on INTERFACE
   targets
 Call Stack \(most recent call first\):
diff --git a/Tests/RunCMake/target_compile_features/invalid_args_on_interface.cmake b/Tests/RunCMake/target_compile_features/invalid_args_on_interface.cmake
index 324d0f3846..49d2d827dd 100644
--- a/Tests/RunCMake/target_compile_features/invalid_args_on_interface.cmake
+++ b/Tests/RunCMake/target_compile_features/invalid_args_on_interface.cmake
@@ -1,3 +1,4 @@
+enable_language(CXX)
 
 add_library(main INTERFACE)
 target_compile_features(main PRIVATE cxx_delegating_constructors)
diff --git a/Tests/RunCMake/target_compile_features/no_matching_c_feature-stderr.txt b/Tests/RunCMake/target_compile_features/no_matching_c_feature-stderr.txt
index 96b959cf52..1875d1209e 100644
--- a/Tests/RunCMake/target_compile_features/no_matching_c_feature-stderr.txt
+++ b/Tests/RunCMake/target_compile_features/no_matching_c_feature-stderr.txt
@@ -1,4 +1,4 @@
-CMake Error at no_matching_c_feature.cmake:[0-9][0-9]? \((target_compile_features|message)\):
+CMake Error at no_matching_c_feature.cmake:[0-9]+ \((target_compile_features|message)\):
   The compiler feature "gnu_c_dummy" is not known to C compiler
 
   "GNU"
diff --git a/Tests/RunCMake/target_compile_features/no_matching_c_feature.cmake b/Tests/RunCMake/target_compile_features/no_matching_c_feature.cmake
index a44caf29a3..0e93b41ffc 100644
--- a/Tests/RunCMake/target_compile_features/no_matching_c_feature.cmake
+++ b/Tests/RunCMake/target_compile_features/no_matching_c_feature.cmake
@@ -1,3 +1,4 @@
+enable_language(CXX)
 
 if (NOT ";${CMAKE_C_COMPILE_FEATURES};" MATCHES ";gnu_c_typeof;")
   # Simulate passing the test.
diff --git a/Tests/RunCMake/target_compile_features/no_matching_cxx_feature-stderr.txt b/Tests/RunCMake/target_compile_features/no_matching_cxx_feature-stderr.txt
index f976dfeab7..90d41c9576 100644
--- a/Tests/RunCMake/target_compile_features/no_matching_cxx_feature-stderr.txt
+++ b/Tests/RunCMake/target_compile_features/no_matching_cxx_feature-stderr.txt
@@ -1,4 +1,4 @@
-CMake Error at no_matching_cxx_feature.cmake:[0-9][0-9]? \((target_compile_features|message)\):
+CMake Error at no_matching_cxx_feature.cmake:[0-9]+ \((target_compile_features|message)\):
   The compiler feature "[^"]+" is not known to CXX compiler
 
   "[^"]*"
diff --git a/Tests/RunCMake/target_compile_features/no_matching_cxx_feature.cmake b/Tests/RunCMake/target_compile_features/no_matching_cxx_feature.cmake
index ab1fd76088..4ee3445e85 100644
--- a/Tests/RunCMake/target_compile_features/no_matching_cxx_feature.cmake
+++ b/Tests/RunCMake/target_compile_features/no_matching_cxx_feature.cmake
@@ -1,3 +1,4 @@
+enable_language(CXX)
 
 if (NOT ";${CMAKE_CXX_COMPILE_FEATURES};" MATCHES ";gnu_cxx_typeof;"
     AND NOT ";${CMAKE_CXX_COMPILE_FEATURES};" MATCHES ";msvc_cxx_sealed;" )
diff --git a/Tests/RunCMake/target_compile_features/no_target-stderr.txt b/Tests/RunCMake/target_compile_features/no_target-stderr.txt
index 323ba7a901..65974b4d6c 100644
--- a/Tests/RunCMake/target_compile_features/no_target-stderr.txt
+++ b/Tests/RunCMake/target_compile_features/no_target-stderr.txt
@@ -1,4 +1,4 @@
-CMake Error at no_target.cmake:2 \(target_compile_features\):
+CMake Error at no_target.cmake:[0-9]+ \(target_compile_features\):
   Cannot specify compile features for target "main" which is not built by
   this project.
 Call Stack \(most recent call first\):
diff --git a/Tests/RunCMake/target_compile_features/no_target.cmake b/Tests/RunCMake/target_compile_features/no_target.cmake
index 3f0afe273f..a514de86a7 100644
--- a/Tests/RunCMake/target_compile_features/no_target.cmake
+++ b/Tests/RunCMake/target_compile_features/no_target.cmake
@@ -1,2 +1,3 @@
+enable_language(CXX)
 
 target_compile_features(main INTERFACE cxx_delegating_constructors)
diff --git a/Tests/RunCMake/target_compile_features/not_a_c_feature-stderr.txt b/Tests/RunCMake/target_compile_features/not_a_c_feature-stderr.txt
index 6dd00f359a..493c5826c6 100644
--- a/Tests/RunCMake/target_compile_features/not_a_c_feature-stderr.txt
+++ b/Tests/RunCMake/target_compile_features/not_a_c_feature-stderr.txt
@@ -1,4 +1,4 @@
-CMake Error at not_a_c_feature.cmake:3 \(target_compile_features\):
+CMake Error at not_a_c_feature.cmake:[0-9]+ \(target_compile_features\):
   target_compile_features specified unknown feature "c_not_a_feature" for
   target "main".
 Call Stack \(most recent call first\):
diff --git a/Tests/RunCMake/target_compile_features/not_a_c_feature.cmake b/Tests/RunCMake/target_compile_features/not_a_c_feature.cmake
index 0420698bc9..f5d70d0935 100644
--- a/Tests/RunCMake/target_compile_features/not_a_c_feature.cmake
+++ b/Tests/RunCMake/target_compile_features/not_a_c_feature.cmake
@@ -1,3 +1,4 @@
+enable_language(C)
 
 add_executable(main empty.c)
 target_compile_features(main
diff --git a/Tests/RunCMake/target_compile_features/not_a_cxx_feature-stderr.txt b/Tests/RunCMake/target_compile_features/not_a_cxx_feature-stderr.txt
index efa2bad5f8..3dbf0e6549 100644
--- a/Tests/RunCMake/target_compile_features/not_a_cxx_feature-stderr.txt
+++ b/Tests/RunCMake/target_compile_features/not_a_cxx_feature-stderr.txt
@@ -1,4 +1,4 @@
-CMake Error at not_a_cxx_feature.cmake:3 \(target_compile_features\):
+CMake Error at not_a_cxx_feature.cmake:[0-9]+ \(target_compile_features\):
   target_compile_features specified unknown feature "cxx_not_a_feature" for
   target "main".
 Call Stack \(most recent call first\):
diff --git a/Tests/RunCMake/target_compile_features/not_a_cxx_feature.cmake b/Tests/RunCMake/target_compile_features/not_a_cxx_feature.cmake
index 0207b724de..bc3a8c4f68 100644
--- a/Tests/RunCMake/target_compile_features/not_a_cxx_feature.cmake
+++ b/Tests/RunCMake/target_compile_features/not_a_cxx_feature.cmake
@@ -1,3 +1,4 @@
+enable_language(CXX)
 
 add_executable(main empty.cpp)
 target_compile_features(main
diff --git a/Tests/RunCMake/target_compile_features/not_enough_args-stderr.txt b/Tests/RunCMake/target_compile_features/not_enough_args-stderr.txt
index 2f8d812431..c0c2efac48 100644
--- a/Tests/RunCMake/target_compile_features/not_enough_args-stderr.txt
+++ b/Tests/RunCMake/target_compile_features/not_enough_args-stderr.txt
@@ -1,4 +1,4 @@
-CMake Error at not_enough_args.cmake:3 \(target_compile_features\):
+CMake Error at not_enough_args.cmake:[0-9]+ \(target_compile_features\):
   target_compile_features called with incorrect number of arguments
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)
diff --git a/Tests/RunCMake/target_compile_features/not_enough_args.cmake b/Tests/RunCMake/target_compile_features/not_enough_args.cmake
index 95612300ad..f5b719863c 100644
--- a/Tests/RunCMake/target_compile_features/not_enough_args.cmake
+++ b/Tests/RunCMake/target_compile_features/not_enough_args.cmake
@@ -1,3 +1,4 @@
+enable_language(CXX)
 
 add_executable(main empty.cpp)
 target_compile_features(main)
diff --git a/Tests/RunCMake/target_compile_features/utility_target-stderr.txt b/Tests/RunCMake/target_compile_features/utility_target-stderr.txt
index d23905995e..ff03310d13 100644
--- a/Tests/RunCMake/target_compile_features/utility_target-stderr.txt
+++ b/Tests/RunCMake/target_compile_features/utility_target-stderr.txt
@@ -1,4 +1,4 @@
-CMake Error at utility_target.cmake:4 \(target_compile_features\):
+CMake Error at utility_target.cmake:[0-9]+ \(target_compile_features\):
   target_compile_features called with non-compilable target type
 Call Stack \(most recent call first\):
   CMakeLists.txt:3 \(include\)

From e03a1b3b6185e36a5905db3d2551c9575fb074aa Mon Sep 17 00:00:00 2001
From: Brad King <brad.king@kitware.com>
Date: Mon, 26 Jun 2017 13:52:26 -0400
Subject: [PATCH 2/2] target_compile_features: Do not crash on non-enabled
 language

Fixes: #17011
---
 Source/cmMakefile.cxx                         | 21 +++++++++++++++++--
 .../RunCMakeTest.cmake                        |  1 +
 .../cxx_not_enabled-result.txt                |  1 +
 .../cxx_not_enabled-stderr.txt                |  4 ++++
 .../cxx_not_enabled.cmake                     |  2 ++
 5 files changed, 27 insertions(+), 2 deletions(-)
 create mode 100644 Tests/RunCMake/target_compile_features/cxx_not_enabled-result.txt
 create mode 100644 Tests/RunCMake/target_compile_features/cxx_not_enabled-stderr.txt
 create mode 100644 Tests/RunCMake/target_compile_features/cxx_not_enabled.cmake

diff --git a/Source/cmMakefile.cxx b/Source/cmMakefile.cxx
index 802a427a66..608b18a46a 100644
--- a/Source/cmMakefile.cxx
+++ b/Source/cmMakefile.cxx
@@ -4190,6 +4190,23 @@ bool cmMakefile::CompileFeatureKnown(cmTarget const* target,
 const char* cmMakefile::CompileFeaturesAvailable(const std::string& lang,
                                                  std::string* error) const
 {
+  if (!this->GlobalGenerator->GetLanguageEnabled(lang)) {
+    std::ostringstream e;
+    if (error) {
+      e << "cannot";
+    } else {
+      e << "Cannot";
+    }
+    e << " use features from non-enabled language " << lang;
+    if (error) {
+      *error = e.str();
+    } else {
+      this->GetCMakeInstance()->IssueMessage(cmake::FATAL_ERROR, e.str(),
+                                             this->Backtrace);
+    }
+    return CM_NULLPTR;
+  }
+
   const char* featuresKnown =
     this->GetDefinition("CMAKE_" + lang + "_COMPILE_FEATURES");
 
@@ -4201,9 +4218,9 @@ const char* cmMakefile::CompileFeaturesAvailable(const std::string& lang,
       e << "No";
     }
     e << " known features for " << lang << " compiler\n\""
-      << this->GetDefinition("CMAKE_" + lang + "_COMPILER_ID")
+      << this->GetSafeDefinition("CMAKE_" + lang + "_COMPILER_ID")
       << "\"\nversion "
-      << this->GetDefinition("CMAKE_" + lang + "_COMPILER_VERSION") << ".";
+      << this->GetSafeDefinition("CMAKE_" + lang + "_COMPILER_VERSION") << ".";
     if (error) {
       *error = e.str();
     } else {
diff --git a/Tests/RunCMake/target_compile_features/RunCMakeTest.cmake b/Tests/RunCMake/target_compile_features/RunCMakeTest.cmake
index 33faf2bbb8..1f67f11a09 100644
--- a/Tests/RunCMake/target_compile_features/RunCMakeTest.cmake
+++ b/Tests/RunCMake/target_compile_features/RunCMakeTest.cmake
@@ -11,3 +11,4 @@ run_cmake(not_a_cxx_feature)
 run_cmake(no_matching_cxx_feature)
 run_cmake(not_a_c_feature)
 run_cmake(no_matching_c_feature)
+run_cmake(cxx_not_enabled)
diff --git a/Tests/RunCMake/target_compile_features/cxx_not_enabled-result.txt b/Tests/RunCMake/target_compile_features/cxx_not_enabled-result.txt
new file mode 100644
index 0000000000..d00491fd7e
--- /dev/null
+++ b/Tests/RunCMake/target_compile_features/cxx_not_enabled-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/target_compile_features/cxx_not_enabled-stderr.txt b/Tests/RunCMake/target_compile_features/cxx_not_enabled-stderr.txt
new file mode 100644
index 0000000000..4f707c7b9a
--- /dev/null
+++ b/Tests/RunCMake/target_compile_features/cxx_not_enabled-stderr.txt
@@ -0,0 +1,4 @@
+^CMake Error at cxx_not_enabled.cmake:[0-9]+ \(target_compile_features\):
+  target_compile_features cannot use features from non-enabled language CXX
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)$
diff --git a/Tests/RunCMake/target_compile_features/cxx_not_enabled.cmake b/Tests/RunCMake/target_compile_features/cxx_not_enabled.cmake
new file mode 100644
index 0000000000..b7e91196e4
--- /dev/null
+++ b/Tests/RunCMake/target_compile_features/cxx_not_enabled.cmake
@@ -0,0 +1,2 @@
+add_executable(main empty.c)
+target_compile_features(main PRIVATE cxx_decltype)