Detect CMake warnings and errors in build output.

Fix niggly in ExternalProject that would inadvertently
create a log file of output when a command was explicitly
set to the empty string.

Also, increase the default value for showing context
around build errors to 10 lines, up from 6. Also add
the ability to customize this setting so that users
can put it back to 6 or even lower if they want, or
show more if they want.

2 files changed, 21 insertions, 6 deletions

diff --git a/Modules/ExternalProject.cmake b/Modules/ExternalProject.cmake
index 9b35a95..2faa190 100644
--- a/Modules/ExternalProject.cmake
+++ b/Modules/ExternalProject.cmake
@@ -780,7 +780,7 @@ function(ExternalProject_Add_Step name step)
 
   # Wrap with log script?
   get_property(log TARGET ${name} PROPERTY _EP_${step}_LOG)
-  if(log)
+  if(command AND log)
     _ep_write_log_script(${name} ${step} command)
   endif()
 
diff --git a/Source/CTest/cmCTestBuildHandler.cxx b/Source/CTest/cmCTestBuildHandler.cxx
index bc02fbc..619783f 100644
--- a/Source/CTest/cmCTestBuildHandler.cxx
+++ b/Source/CTest/cmCTestBuildHandler.cxx
@@ -65,7 +65,7 @@ static const char* cmCTestErrorMatches[] = {
   "^Unresolved:",
   "Undefined symbols:",
   "^Undefined[ \\t]+first referenced",
-  "^CMake Error:",
+  "^CMake Error.*:",
   ":[ \\t]cannot find",
   ":[ \\t]can't find",
   ": \\*\\*\\* No rule to make target \\`.*\\'.  Stop",
@@ -129,6 +129,7 @@ static const char* cmCTestWarningMatches[] = {
   "\\([0-9]*\\): remark #[0-9]*",
   "\".*\", line [0-9]+: remark\\([0-9]*\\):",
   "cc-[0-9]* CC: REMARK File = .*, Line = [0-9]*",
+  "^CMake Warning.*:",
   0
 };
 
@@ -174,8 +175,8 @@ cmCTestWarningErrorFileLine[] = {
 //----------------------------------------------------------------------
 cmCTestBuildHandler::cmCTestBuildHandler()
 {
-  this->MaxPreContext = 6;
-  this->MaxPostContext = 6;
+  this->MaxPreContext = 10;
+  this->MaxPostContext = 10;
 
   this->MaxErrors = 50;
   this->MaxWarnings = 50;
@@ -214,8 +215,8 @@ void cmCTestBuildHandler::Initialize()
   this->ErrorsAndWarnings.clear();
   this->LastErrorOrWarning = this->ErrorsAndWarnings.end();
   this->PostContextCount = 0;
-  this->MaxPreContext = 6;
-  this->MaxPostContext = 6;
+  this->MaxPreContext = 10;
+  this->MaxPostContext = 10;
   this->PreContext.clear();
 
   this->TotalErrors = 0;
@@ -249,6 +250,20 @@ void cmCTestBuildHandler::PopulateCustomVectors(cmMakefile *mf)
                              "CTEST_CUSTOM_MAXIMUM_NUMBER_OF_WARNINGS",
                              this->MaxWarnings);
 
+  int n = -1;
+  this->CTest->PopulateCustomInteger(mf, "CTEST_CUSTOM_ERROR_PRE_CONTEXT", n);
+  if (n != -1)
+    {
+    this->MaxPreContext = static_cast<size_t>(n);
+    }
+
+  n = -1;
+  this->CTest->PopulateCustomInteger(mf, "CTEST_CUSTOM_ERROR_POST_CONTEXT", n);
+  if (n != -1)
+    {
+    this->MaxPostContext = static_cast<size_t>(n);
+    }
+
   // Record the user-specified custom warning rules.
   if(const char* customWarningMatchers =
      mf->GetDefinition("CTEST_CUSTOM_WARNING_MATCH"))