Simplify using subprocess.DEVNULL

Co-Authored-By: Jon Dufresne <jon.dufresne@gmail.com>

Tests/helper.py

@@ -321,11 +321,10 @@ def command_succeeds(cmd):
     Runs the command, which must be a list of strings. Returns True if the
     command succeeds, or False if an OSError was raised by subprocess.Popen.
     """
-    with open(os.devnull, "wb") as f:
-        try:
-            subprocess.call(cmd, stdout=f, stderr=subprocess.STDOUT)
-        except OSError:
-            return False
+    try:
+        subprocess.call(cmd, stdout=subprocess.DEVNULL, stderr=subprocess.STDOUT)
+    except OSError:
+        return False
     return True
 
 

setup.py

@@ -164,10 +164,10 @@ def _find_library_dirs_ldconfig():
         expr = r".* => (.*)"
         env = {}
 
-    null = open(os.devnull, "wb")
     try:
-        with null:
-            p = subprocess.Popen(args, stderr=null, stdout=subprocess.PIPE, env=env)
+        p = subprocess.Popen(
+            args, stderr=subprocess.DEVNULL, stdout=subprocess.PIPE, env=env
+        )
     except OSError:  # E.g. command not found
         return []
     [data, _] = p.communicate()

src/PIL/EpsImagePlugin.py

@@ -57,8 +57,7 @@ def has_ghostscript():
         return True
     if not sys.platform.startswith("win"):
         try:
-            with open(os.devnull, "wb") as devnull:
-                subprocess.check_call(["gs", "--version"], stdout=devnull)
+            subprocess.check_call(["gs", "--version"], stdout=subprocess.DEVNULL)
             return True
         except OSError:
             # No Ghostscript

src/PIL/GifImagePlugin.py

@@ -623,20 +623,20 @@ def _save_netpbm(im, fp, filename):
 
     with open(filename, "wb") as f:
         if im.mode != "RGB":
-            with open(os.devnull, "wb") as devnull:
-                subprocess.check_call(["ppmtogif", tempfile], stdout=f, stderr=devnull)
+            subprocess.check_call(
+                ["ppmtogif", tempfile], stdout=f, stderr=subprocess.DEVNULL
+            )
         else:
             # Pipe ppmquant output into ppmtogif
             # "ppmquant 256 %s | ppmtogif > %s" % (tempfile, filename)
             quant_cmd = ["ppmquant", "256", tempfile]
             togif_cmd = ["ppmtogif"]
-            with open(os.devnull, "wb") as devnull:
-                quant_proc = subprocess.Popen(
-                    quant_cmd, stdout=subprocess.PIPE, stderr=devnull
-                )
-                togif_proc = subprocess.Popen(
-                    togif_cmd, stdin=quant_proc.stdout, stdout=f, stderr=devnull
-                )
+            quant_proc = subprocess.Popen(
+                quant_cmd, stdout=subprocess.PIPE, stderr=subprocess.DEVNULL
+            )
+            togif_proc = subprocess.Popen(
+                togif_cmd, stdin=quant_proc.stdout, stdout=f, stderr=subprocess.DEVNULL
+            )
 
             # Allow ppmquant to receive SIGPIPE if ppmtogif exits
             quant_proc.stdout.close()

src/PIL/IcnsImagePlugin.py

@@ -336,10 +336,9 @@ def _save(im, fp, filename):
     # iconutil -c icns -o {} {}
 
     convert_cmd = ["iconutil", "-c", "icns", "-o", filename, iconset]
-    with open(os.devnull, "wb") as devnull:
-        convert_proc = subprocess.Popen(
-            convert_cmd, stdout=subprocess.PIPE, stderr=devnull
-        )
+    convert_proc = subprocess.Popen(
+        convert_cmd, stdout=subprocess.PIPE, stderr=subprocess.DEVNULL
+    )
 
     convert_proc.stdout.close()