Make file handing in setup.py more robust by using context managers to properly

close files.

setup.py

@@ -423,7 +423,8 @@ class PyBuildExt(build_ext):
         missing = []
 
         config_h = sysconfig.get_config_h_filename()
-        config_h_vars = sysconfig.parse_config_h(open(config_h))
+        with open(config_h) as file:
+            config_h_vars = sysconfig.parse_config_h(file)
 
         platform = self.get_platform()
         srcdir = sysconfig.get_config_var('srcdir')
@@ -556,17 +557,17 @@ class PyBuildExt(build_ext):
                 os.makedirs(self.build_temp)
             ret = os.system("ldd %s > %s" % (do_readline, tmpfile))
             if ret >> 8 == 0:
-                fp = open(tmpfile)
+                with open(tmpfile) as fp:
                     for ln in fp:
                         if 'curses' in ln:
                             readline_termcap_library = re.sub(
                                 r'.*lib(n?cursesw?)\.so.*', r'\1', ln
                             ).rstrip()
                             break
-                    if 'tinfo' in ln: # termcap interface split out from ncurses
+                        # termcap interface split out from ncurses
+                        if 'tinfo' in ln:
                             readline_termcap_library = 'tinfo'
                             break
-                fp.close()
             os.unlink(tmpfile)
         # Issue 7384: If readline is already linked against curses,
         # use the same library for the readline and curses modules.
@@ -675,7 +676,7 @@ class PyBuildExt(build_ext):
             if sys.platform == 'darwin' and is_macosx_sdk_path(name):
                 name = os.path.join(macosx_sdk_root(), name[1:])
             try:
-                incfile = open(name, 'r')
+                with open(name, 'r') as incfile:
                     for line in incfile:
                         m = openssl_ver_re.match(line)
                         if m:
@@ -825,7 +826,8 @@ class PyBuildExt(build_ext):
 
                 if db_setup_debug: print("db: looking for db.h in", f)
                 if os.path.exists(f):
-                    f = open(f, "rb").read()
+                    with open(f, 'rb') as file:
+                        f = file.read()
                     m = re.search(br"#define\WDB_VERSION_MAJOR\W(\d+)", f)
                     if m:
                         db_major = int(m.group(1))
@@ -945,7 +947,8 @@ class PyBuildExt(build_ext):
 
             if os.path.exists(f):
                 if sqlite_setup_debug: print("sqlite: found %s"%f)
-                incf = open(f).read()
+                with open(f) as file:
+                    incf = file.read()
                 m = re.search(
                     r'\s*.*#\s*.*define\s.*SQLITE_VERSION\W*"(.*)"', incf)
                 if m:
@@ -1170,7 +1173,7 @@ class PyBuildExt(build_ext):
             zlib_h = zlib_inc[0] + '/zlib.h'
             version = '"0.0.0"'
             version_req = '"1.1.3"'
-            fp = open(zlib_h)
+            with open(zlib_h) as fp:
                 while 1:
                     line = fp.readline()
                     if not line:
@@ -1430,14 +1433,13 @@ class PyBuildExt(build_ext):
             os.system("file %s/Tk.framework/Tk | grep 'for architecture' > %s"%(os.path.join(sysroot, F[1:]), tmpfile))
         else:
             os.system("file %s/Tk.framework/Tk | grep 'for architecture' > %s"%(F, tmpfile))
-        fp = open(tmpfile)
 
+        with open(tmpfile) as fp:
             detected_archs = []
             for ln in fp:
                 a = ln.split()[-1]
                 if a in archs:
                     detected_archs.append(ln.split()[-1])
-        fp.close()
         os.unlink(tmpfile)
 
         for a in detected_archs:
@@ -1708,7 +1710,7 @@ class PyBuildExt(build_ext):
             ffi_inc = find_file('ffi.h', [], inc_dirs)
         if ffi_inc is not None:
             ffi_h = ffi_inc[0] + '/ffi.h'
-            fp = open(ffi_h)
+            with open(ffi_h) as fp:
                 while 1:
                     line = fp.readline()
                     if not line: