Query the CDash web API to automate CDash version detection.

Source/cmCTest.cxx

@@ -305,8 +305,7 @@ bool cmCTest::ShouldCompressTestOutput()
 {
   if(!this->ComputedCompressOutput)
     {
-    std::string cdashVersion = 
-      this->GetCTestConfiguration("CDashVersion");
+    std::string cdashVersion = this->GetCDashVersion();
     //version >= 1.6?
     bool cdashSupportsGzip = cmSystemTools::VersionCompare(
       cmSystemTools::OP_GREATER, cdashVersion.c_str(), "1.6") ||
@@ -318,6 +317,19 @@ bool cmCTest::ShouldCompressTestOutput()
   return this->CompressTestOutput;
 }
 
+//----------------------------------------------------------------------------
+std::string cmCTest::GetCDashVersion()
+{
+  //First query the server.  If that fails, fall back to the local setting
+  std::string response;
+  std::string url = "http://";
+  url += this->GetCTestConfiguration("DropSite") + "/CDash/api/getversion.php";
+  
+  int res = cmSystemTools::HTTPRequest(url, cmSystemTools::HTTP_GET, response);
+  
+  return res ? this->GetCTestConfiguration("CDashVersion") : response;
+}
+
 //----------------------------------------------------------------------------
 cmCTest::Part cmCTest::GetPartFromName(const char* name)
 {

Source/cmCTest.h

@@ -197,6 +197,8 @@ public:
 
   bool ShouldCompressTestOutput();
 
+  std::string GetCDashVersion();
+
   //Used for parallel ctest job scheduling
   std::string GetScheduleType() { return this->ScheduleType; }
   void SetScheduleType(std::string type) { this->ScheduleType = type; }