From 1dae3a81011d386206a6eb02d220da415e512716 Mon Sep 17 00:00:00 2001
From: Frederich Munch <marsupial@users.noreply.github.com>
Date: Tue, 7 Feb 2017 16:04:59 -0500
Subject: [PATCH 1/2] Revert "Must flush stdout, else a "lazy" stdout will not
 flush before prompt."

This reverts commit bd6cbaf3b69f1bf52055c4d7071d9174b97c7a9d.
---
 lib/UserInterface/textinput/TerminalDisplayUnix.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/UserInterface/textinput/TerminalDisplayUnix.cpp b/lib/UserInterface/textinput/TerminalDisplayUnix.cpp
index 5db2ea6e79..291788c5c3 100644
--- a/lib/UserInterface/textinput/TerminalDisplayUnix.cpp
+++ b/lib/UserInterface/textinput/TerminalDisplayUnix.cpp
@@ -124,8 +124,8 @@ namespace textinput {
     }
   }
 
-// Don't rely on flushing here.
-#define SYNC_OUT(fd) if (fd==STDOUT_FILENO) { ::fflush(stdout); }
+// Don't rely on flushing here. REALLY, try to fix it elsewhere!
+#define SYNC_OUT(fd) /*if (fd==STDOUT_FILENO) { ::fflush(stdout); } }*/
 
   TerminalDisplayUnix::~TerminalDisplayUnix() {
     Detach();

From ed37482d5174345cd3333a3c1f503bf99a48c793 Mon Sep 17 00:00:00 2001
From: Frederich Munch <marsupial@users.noreply.github.com>
Date: Tue, 7 Feb 2017 20:00:54 -0500
Subject: [PATCH 2/2] Fix stdout being reopened without line buffering if
 redirection occurs before output has been written.

---
 lib/MetaProcessor/MetaProcessor.cpp | 29 +++++++++++++++++------------
 1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/lib/MetaProcessor/MetaProcessor.cpp b/lib/MetaProcessor/MetaProcessor.cpp
index a9fea4f801..77373895a6 100644
--- a/lib/MetaProcessor/MetaProcessor.cpp
+++ b/lib/MetaProcessor/MetaProcessor.cpp
@@ -135,22 +135,18 @@ namespace cling {
     }
 
     // Restore stdstream from backup and close the backup
-    void close(int oldfd, int newfd) {
+    void close(int &oldfd, int newfd) {
       assert((newfd == STDOUT_FILENO || newfd == STDERR_FILENO) && "Not std FD");
       assert(oldfd == m_Bak[newfd == STDERR_FILENO] && "Not backup FD");
       if (oldfd != kInvalidFD) {
         dup2(oldfd, newfd, "RedirectOutput::close");
         ::close(oldfd);
+        oldfd = kInvalidFD;
       }
     }
 
-    void reset(int oldfd, int newfd, FILE *F) {
-      fflush(F);
-      dup2(oldfd, newfd, "RedirectOutput::reset");
-    }
-
     int restore(int FD, FILE *F, MetaProcessor::RedirectionScope Flag,
-                int bakFD) {
+                int &bakFD) {
       // If no backup, we have never redirected the file, so nothing to restore
       if (bakFD != kInvalidFD) {
         // Find the last redirect for the scope, and restore redirection to it
@@ -165,9 +161,10 @@ namespace cling {
         }
 
         // No redirection for this scope, restore to backup
-        reset(bakFD, FD, F);
+        fflush(F);
+        close(bakFD, FD);
       }
-      return bakFD;
+      return kInvalidFD;
     }
 
   public:
@@ -187,6 +184,12 @@ namespace cling {
       // State 2, was tty to begin with, then redirected to stderr and back.
       if (m_TTY == 2)
         ::freopen("CON", "w", stdout);
+#else
+      // If redirection took place without writing anything to the terminal
+      // beforehand (--nologo) then the dup2 relinking stdout will have caused
+      // it to be re-opened without line buffering.
+      if (m_TTY)
+        ::setvbuf(stdout, NULL, _IOLBF, BUFSIZ);
 #endif
     }
 
@@ -254,10 +257,12 @@ namespace cling {
         return;
 
       if (toBackup) {
-        if (m_Bak[0] != kInvalidFD)
-          reset(m_Bak[0], STDOUT_FILENO, stdout);
+        if (m_Bak[0] != kInvalidFD) {
+          fflush(stdout);
+          dup2(m_Bak[0], STDOUT_FILENO, "RedirectOutput::resetStdOut");
+        }
       } else if (m_CurStdOut != kInvalidFD)
-        dup2(m_CurStdOut, STDOUT_FILENO, "RedirectOutput::reset");
+        dup2(m_CurStdOut, STDOUT_FILENO, "RedirectOutput::resetStdOut");
     }
 
     bool empty() const {