From b4b5abd17a3357561a3b7b9f7f7916778a719d93 Mon Sep 17 00:00:00 2001
From: Mats Wichmann <mats@linux.com>
Date: Tue, 14 Aug 2018 15:00:29 -0600
Subject: Redo fix for file closing in SCons.Action._subproc

When the _subproc wrapper is called, a keyword dictionary is used to
hold open file objects if any were indicated as being redirected to
os.devull.  These objects just go missing when SCons.Action._subproc
is done.  A previous iteration registered the close method of the object
with atexit, which made Python 3 happy the open file resources were not
leaking, but has some unexpected side effects. Apparently Action cannot
import either atexit or the SCons equivalent, SCons.exitfuncs without
triggering these effects.

As an alternative, close the objects in the parent's kw dictionary that
have close methods after the subprocess.Popen object has been created.

Signed-off-by: Mats Wichmann <mats@linux.com>
---
 src/engine/SCons/Action.py | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/src/engine/SCons/Action.py b/src/engine/SCons/Action.py
index 249363f..32ceaa9 100644
--- a/src/engine/SCons/Action.py
+++ b/src/engine/SCons/Action.py
@@ -107,7 +107,6 @@ import sys
 import subprocess
 import itertools
 import inspect
-import atexit
 
 import SCons.Debug
 from SCons.Debug import logInstanceCreation
@@ -116,8 +115,7 @@ import SCons.Util
 import SCons.Subst
 
 # we use these a lot, so try to optimize them
-is_String = SCons.Util.is_String
-is_List = SCons.Util.is_List
+from SCons.Util import is_String, is_List
 
 class _null(object):
     pass
@@ -773,15 +771,12 @@ def _subproc(scons_env, cmd, error = 'ignore', **kw):
     io = kw.get('stdin')
     if is_String(io) and io == 'devnull':
         kw['stdin'] = open(os.devnull)
-        atexit.register(kw['stdin'].close)
     io = kw.get('stdout')
     if is_String(io) and io == 'devnull':
         kw['stdout'] = open(os.devnull, 'w')
-        atexit.register(kw['stdout'].close)
     io = kw.get('stderr')
     if is_String(io) and io == 'devnull':
         kw['stderr'] = open(os.devnull, 'w')
-        atexit.register(kw['stderr'].close)
 
     # Figure out what shell environment to use
     ENV = kw.get('env', None)
@@ -807,7 +802,7 @@ def _subproc(scons_env, cmd, error = 'ignore', **kw):
     kw['env'] = new_env
 
     try:
-        return subprocess.Popen(cmd, **kw)
+        pobj =  subprocess.Popen(cmd, **kw)
     except EnvironmentError as e:
         if error == 'raise': raise
         # return a dummy Popen instance that only returns error
@@ -821,7 +816,14 @@ def _subproc(scons_env, cmd, error = 'ignore', **kw):
                 def readline(self): return ''
                 def __iter__(self): return iter(())
             stdout = stderr = f()
-        return dummyPopen(e)
+        pobj = dummyPopen(e)
+    finally:
+        # clean up open file handles stored in parent's kw
+        import io
+        for k, v in kw.items():
+            if hasattr(v, 'close'):
+                v.close()
+        return pobj
 
 
 class CommandAction(_ActionAction):
-- 
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