build_command: Fail early without CMAKE_MAKE_PROGRAM (#14005)

If CMAKE_MAKE_PROGRAM is not set fail with an error message instead of
crashing.  Suggest calling project() or enable_language() first to
ensure that CMAKE_MAKE_PROGRAM is set.

6 files changed, 23 insertions, 1 deletions

diff --git a/Source/cmBuildCommand.cxx b/Source/cmBuildCommand.cxx
index 3722ab6..91d55a5 100644
--- a/Source/cmBuildCommand.cxx
+++ b/Source/cmBuildCommand.cxx
@@ -87,6 +87,14 @@ bool cmBuildCommand
 
   const char* makeprogram
     = this->Makefile->GetDefinition("CMAKE_MAKE_PROGRAM");
+  if(!makeprogram)
+    {
+    this->Makefile->IssueMessage(
+      cmake::FATAL_ERROR,
+      "build_command() requires CMAKE_MAKE_PROGRAM to be defined.  "
+      "Call project() or enable_language() first.");
+    return true;
+    }
 
   // If null/empty CONFIGURATION argument, GenerateBuildCommand uses 'Debug'
   // in the currently implemented multi-configuration global generators...
diff --git a/Tests/RunCMake/build_command/BeforeProject-result.txt b/Tests/RunCMake/build_command/BeforeProject-result.txt
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/Tests/RunCMake/build_command/BeforeProject-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/build_command/BeforeProject-stderr.txt b/Tests/RunCMake/build_command/BeforeProject-stderr.txt
new file mode 100644
index 0000000..d3d7661
--- /dev/null
+++ b/Tests/RunCMake/build_command/BeforeProject-stderr.txt
@@ -0,0 +1,5 @@
+CMake Error at BeforeProject.cmake:[0-9]+ \(build_command\):
+  build_command\(\) requires CMAKE_MAKE_PROGRAM to be defined.  Call project\(\)
+  or enable_language\(\) first.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:[0-9]+ \(include\)
diff --git a/Tests/RunCMake/build_command/BeforeProject.cmake b/Tests/RunCMake/build_command/BeforeProject.cmake
new file mode 100644
index 0000000..15788d1
--- /dev/null
+++ b/Tests/RunCMake/build_command/BeforeProject.cmake
@@ -0,0 +1,2 @@
+build_command(MAKECOMMAND_DEFAULT_VALUE)
+project(${RunCMake_TEST} NONE)
diff --git a/Tests/RunCMake/build_command/CMakeLists.txt b/Tests/RunCMake/build_command/CMakeLists.txt
index e8db6b0..f6e84c0 100644
--- a/Tests/RunCMake/build_command/CMakeLists.txt
+++ b/Tests/RunCMake/build_command/CMakeLists.txt
@@ -1,3 +1,5 @@
 cmake_minimum_required(VERSION 2.8)
-project(${RunCMake_TEST} NONE)
+if(NOT NoProject)
+  project(${RunCMake_TEST} NONE)
+endif()
 include(${RunCMake_TEST}.cmake)
diff --git a/Tests/RunCMake/build_command/RunCMakeTest.cmake b/Tests/RunCMake/build_command/RunCMakeTest.cmake
index 4525c57..eaa1d77 100644
--- a/Tests/RunCMake/build_command/RunCMakeTest.cmake
+++ b/Tests/RunCMake/build_command/RunCMakeTest.cmake
@@ -2,3 +2,7 @@ include(RunCMake)
 
 run_cmake(ErrorsOFF)
 run_cmake(ErrorsON)
+
+set(RunCMake_TEST_OPTIONS -DNoProject=1)
+run_cmake(BeforeProject)
+unset(RunCMake_TEST_OPTIONS)