# HG changeset patch
# User jbe
# Date 1497743905 -7200
# Node ID 42ddff7319e0a144e53fede990919775ff7a1deb
# Parent  5b1c4f76e44fb8877726f350591fe688a82df415
Avoid blocking of execute.command{...} if child process closes file descriptors but doesn't terminate

diff -r 5b1c4f76e44f -r 42ddff7319e0 framework/env/execute/command.lua
--- a/framework/env/execute/command.lua	Mon Jun 12 03:32:23 2017 +0200
+++ b/framework/env/execute/command.lua	Sun Jun 18 01:58:25 2017 +0200
@@ -44,8 +44,14 @@
   local process, errmsg = moonbridge_io.exec(table.unpack(args.command))
   if not process then return nil, errmsg end
 
-  local read_fds = {[process.stdout] = true, [process.stderr] = true}
-  local write_fds = {[process.stdin] = true}
+  local read_fds = {
+    [process] = true,
+    [process.stdout] = true,
+    [process.stderr] = true
+  }
+  local write_fds = {
+    [process.stdin] = true
+  }
   if args.db then
     read_fds[args.db.fd] = true
   end
@@ -61,7 +67,10 @@
   end
   write(args.stdin_data or "")
 
+  local status
+
   while
+    not status or
     read_fds[process.stdout] or read_fds[process.stderr] or
     write_fds[process.stdin]
   do
@@ -69,7 +78,9 @@
     local pollready, pollmsg, pollterm =
       poll(read_fds, write_fds, timeout, args.abortable)
     if not pollready then
-      process:kill():wait()
+      if not status then
+        process:kill():wait()
+      end
       if pollterm then
         if args.abort_handler then args.abort_handler(pollmsg) end
       else
@@ -77,6 +88,12 @@
       end
       return return_error(pollmsg)
     end
+    if not status then
+      status = process:wait_nb()
+      if status then
+        read_fds[process] = nil
+      end
+    end
     if args.db then
       local channel, payload, pid = db:wait(0)
       if channel then
@@ -123,8 +140,6 @@
     write()
   end
 
-  local status = process:wait()
-
   if status < 0 then
     if args.signal_handler then
       args.signal_handler(-status)