CTest: Capture test stdout/stderr through one pipe (#15600)

Use the KWSys Process "MergeOutput" option to give each test child
process the same pipe for both stdout and stderr.  This allows natural
merging of stdout and stderr together instead of merging on arbitrary
buffered read boundaries as before.

1 files changed, 4 insertions, 15 deletions

diff --git a/Source/CTest/cmProcess.cxx b/Source/CTest/cmProcess.cxx
index e1bd02b..0c25f40 100644
--- a/Source/CTest/cmProcess.cxx
+++ b/Source/CTest/cmProcess.cxx
@@ -62,6 +62,7 @@ bool cmProcess::StartProcess()
                                      this->WorkingDirectory.c_str());
     }
   cmsysProcess_SetTimeout(this->Process, this->Timeout);
+  cmsysProcess_SetOption(this->Process, cmsysProcess_Option_MergeOutput, 1);
   cmsysProcess_Execute(this->Process);
   return (cmsysProcess_GetState(this->Process)
           == cmsysProcess_State_Executing);
@@ -124,14 +125,10 @@ int cmProcess::GetNextOutputLine(std::string& line, double timeout)
   for(;;)
     {
     // Look for lines already buffered.
-    if(this->StdOut.GetLine(line))
+    if(this->Output.GetLine(line))
       {
       return cmsysProcess_Pipe_STDOUT;
       }
-    else if(this->StdErr.GetLine(line))
-      {
-      return cmsysProcess_Pipe_STDERR;
-      }
 
     // Check for more data from the process.
     char* data;
@@ -143,11 +140,7 @@ int cmProcess::GetNextOutputLine(std::string& line, double timeout)
       }
     else if(p == cmsysProcess_Pipe_STDOUT)
       {
-      this->StdOut.insert(this->StdOut.end(), data, data+length);
-      }
-    else if(p == cmsysProcess_Pipe_STDERR)
-      {
-      this->StdErr.insert(this->StdErr.end(), data, data+length);
+      this->Output.insert(this->Output.end(), data, data+length);
       }
     else // p == cmsysProcess_Pipe_None
       {
@@ -157,14 +150,10 @@ int cmProcess::GetNextOutputLine(std::string& line, double timeout)
     }
 
   // Look for partial last lines.
-  if(this->StdOut.GetLast(line))
+  if(this->Output.GetLast(line))
     {
     return cmsysProcess_Pipe_STDOUT;
     }
-  else if(this->StdErr.GetLast(line))
-    {
-    return cmsysProcess_Pipe_STDERR;
-    }
 
   // No more data.  Wait for process exit.
   if(!cmsysProcess_WaitForExit(this->Process, &timeout))