cmake: On configure error suggest looking at CMake*.log files

When CMake reports failure to configure a project, especially when the
toolchain does not initialize properly, the true reason may be clear
from reading the CMakeFiles/CMake(Output|Error).log files.  Advise users
to look at these files if they exist when configuration fails.

Add RunCMake.Configure test to check that the log files are mentioned
when configuration fails.

Source/cmGlobalGenerator.cxx

@@ -892,12 +892,28 @@ void cmGlobalGenerator::Configure()
 
   if ( this->CMakeInstance->GetWorkingMode() == cmake::NORMAL_MODE)
     {
-    const char* msg = "Configuring done";
+    cmOStringStream msg;
     if(cmSystemTools::GetErrorOccuredFlag())
       {
-      msg = "Configuring incomplete, errors occurred!";
+      msg << "Configuring incomplete, errors occurred!";
+      const char* logs[] = {"CMakeOutput.log", "CMakeError.log", 0};
+      for(const char** log = logs; *log; ++log)
+        {
+        std::string f = this->CMakeInstance->GetHomeOutputDirectory();
+        f += this->CMakeInstance->GetCMakeFilesDirectory();
+        f += "/";
+        f += *log;
+        if(cmSystemTools::FileExists(f.c_str()))
+          {
+          msg << "\nSee also \"" << f << "\".";
           }
-    this->CMakeInstance->UpdateProgress(msg, -1);
+        }
+      }
+    else
+      {
+      msg << "Configuring done";
+      }
+    this->CMakeInstance->UpdateProgress(msg.str().c_str(), -1);
     }
 }
 

Tests/RunCMake/CMakeLists.txt

@@ -56,6 +56,7 @@ add_RunCMake_test(CTest)
 if(UNIX AND "${CMAKE_TEST_GENERATOR}" MATCHES "Unix Makefiles")
   add_RunCMake_test(CompilerChange)
 endif()
+add_RunCMake_test(Configure)
 add_RunCMake_test(ExternalData)
 add_RunCMake_test(FPHSA)
 add_RunCMake_test(GeneratorExpression)

Tests/RunCMake/Configure/CMakeLists.txt

@@ -0,0 +1,3 @@
+cmake_minimum_required(VERSION 2.8)
+project(${RunCMake_TEST} NONE)
+include(${RunCMake_TEST}.cmake)

Tests/RunCMake/Configure/ErrorLogs-result.txt

@@ -0,0 +1 @@
+1

Tests/RunCMake/Configure/ErrorLogs-stderr.txt

@@ -0,0 +1,4 @@
+CMake Error at ErrorLogs.cmake:3 \(message\):
+  Some error!
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)

Tests/RunCMake/Configure/ErrorLogs-stdout.txt

@@ -0,0 +1,3 @@
+-- Configuring incomplete, errors occurred!
+See also ".*/Tests/RunCMake/Configure/ErrorLogs-build/CMakeFiles/CMakeOutput\.log"\.
+See also ".*/Tests/RunCMake/Configure/ErrorLogs-build/CMakeFiles/CMakeError\.log"\.

Tests/RunCMake/Configure/ErrorLogs.cmake

@@ -0,0 +1,3 @@
+file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
+  "Some detailed error information!\n")
+message(SEND_ERROR "Some error!")

Tests/RunCMake/Configure/RunCMakeTest.cmake

@@ -0,0 +1,3 @@
+include(RunCMake)
+
+run_cmake(ErrorLogs)