From e8ab2487dfd24c3df729dcfb409b687e50591f14 Mon Sep 17 00:00:00 2001
From: Oliver Kisielius <oliver.kisielius@gmail.com>
Date: Fri, 13 Apr 2018 00:00:35 -0400
Subject: [PATCH 1/2] Fix resource warnings under Python 3.6, issue #151

---
 pygraphviz/agraph.py | 58 ++++++++++++++++++++++----------------------
 1 file changed, 29 insertions(+), 29 deletions(-)

diff --git a/pygraphviz/agraph.py b/pygraphviz/agraph.py
index 4cb8fc24..2e60c05b 100644
--- a/pygraphviz/agraph.py
+++ b/pygraphviz/agraph.py
@@ -1304,35 +1304,35 @@ def _run_prog(self, prog='nop', args=''):
         runprog = r'"%s"' % self._get_prog(prog)
         cmd = ' '.join([runprog, args])
         dotargs = shlex.split(cmd)
-        p = subprocess.Popen(dotargs,
-                             shell=False,
-                             stdin=subprocess.PIPE,
-                             stdout=subprocess.PIPE,
-                             stderr=subprocess.PIPE,
-                             close_fds=False)
-        (child_stdin,
-         child_stdout,
-         child_stderr) = (p.stdin, p.stdout, p.stderr)
-        # Use threading to avoid blocking
-        data = []
-        errors = []
-        threads = [PipeReader(data, child_stdout),
-                   PipeReader(errors, child_stderr)]
-        for t in threads:
-            t.start()
-
-        self.write(child_stdin)
-        child_stdin.close()
-
-        for t in threads:
-            t.join()
-
-        if not data:
-            raise IOError(b"".join(errors).decode(self.encoding))
-
-        if len(errors) > 0:
-            warnings.warn(b"".join(errors).decode(self.encoding), RuntimeWarning)
-        return b"".join(data)
+        with subprocess.Popen(dotargs,
+                              shell=False,
+                              stdin=subprocess.PIPE,
+                              stdout=subprocess.PIPE,
+                              stderr=subprocess.PIPE,
+                              close_fds=False) as p:
+            (child_stdin,
+             child_stdout,
+             child_stderr) = (p.stdin, p.stdout, p.stderr)
+            # Use threading to avoid blocking
+            data = []
+            errors = []
+            threads = [PipeReader(data, child_stdout),
+                       PipeReader(errors, child_stderr)]
+            for t in threads:
+                t.start()
+
+            self.write(child_stdin)
+            child_stdin.close()
+
+            for t in threads:
+                t.join()
+
+            if not data:
+                raise IOError(b"".join(errors).decode(self.encoding))
+
+            if len(errors) > 0:
+                warnings.warn(b"".join(errors).decode(self.encoding), RuntimeWarning)
+            return b"".join(data)
 
     def layout(self, prog='neato', args=''):
         """Assign positions to nodes in graph.

From 3b296ffa13a40b804b2a5e2c41ff620d638dd852 Mon Sep 17 00:00:00 2001
From: Oliver Kisielius <oliver.kisielius@gmail.com>
Date: Fri, 13 Apr 2018 00:13:38 -0400
Subject: [PATCH 2/2] Less ham-handed than previous commit

---
 pygraphviz/agraph.py | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/pygraphviz/agraph.py b/pygraphviz/agraph.py
index 2e60c05b..9a66cf81 100644
--- a/pygraphviz/agraph.py
+++ b/pygraphviz/agraph.py
@@ -1327,12 +1327,12 @@ def _run_prog(self, prog='nop', args=''):
             for t in threads:
                 t.join()
 
-            if not data:
-                raise IOError(b"".join(errors).decode(self.encoding))
+        if not data:
+            raise IOError(b"".join(errors).decode(self.encoding))
 
-            if len(errors) > 0:
-                warnings.warn(b"".join(errors).decode(self.encoding), RuntimeWarning)
-            return b"".join(data)
+        if len(errors) > 0:
+            warnings.warn(b"".join(errors).decode(self.encoding), RuntimeWarning)
+        return b"".join(data)
 
     def layout(self, prog='neato', args=''):
         """Assign positions to nodes in graph.