replace open(filepath).read() anti-pattern by code that safely and timely closes the file

Cython/Build/Dependencies.py

@@ -91,7 +91,14 @@ def file_hash(filename):
     path = os.path.normpath(filename.encode("UTF-8"))
     m = hashlib.md5(str(len(path)) + ":")
     m.update(path)
-    m.update(open(filename).read())
+    f = open(filename, 'rb')
+    try:
+        data = f.read(65000)
+        while data:
+            m.update(data)
+            data = f.read(65000)
+    finally:
+        f.close()
     return m.hexdigest()
 
 def parse_list(s):

Cython/Compiler/Main.py

@@ -309,7 +309,14 @@ class Context(object):
             position = e.args[2]
             encoding = e.args[0]
 
-            for idx, c in enumerate(open(source_filename, "rb").read()):
+            f = open(source_filename, "rb")
+            try:
+                byte_data = f.read()
+            finally:
+                f.close()
+
+            # FIXME: make this at least a little less inefficient
+            for idx, c in enumerate(byte_data):
                 if c in (ord('\n'), '\n'):
                     line += 1
                     column = 0

Cython/Compiler/Tests/TestParseTreeTransforms.py

@@ -271,13 +271,15 @@ class TestDebugTransform(DebuggerTestCase):
             assert 'puts' in spam_stepinto
             assert 'some_c_function' in spam_stepinto
         except:
-            print open(self.debug_dest).read()
+            f = open(self.debug_dest)
+            try:
+                print(f.read())
+            finally:
+                f.close()
             raise
 
 
 
-
-
 if __name__ == "__main__":
     import unittest
     unittest.main()

Cython/Debugger/Cygdb.py

@@ -35,6 +35,7 @@ def make_command_file(path_to_debug_info, prefix_code='', no_import=False):
 
     fd, tempfilename = tempfile.mkstemp()
     f = os.fdopen(fd, 'w')
+    try:
         f.write(prefix_code)
         f.write('set breakpoint pending on\n')
         f.write("set print pretty on\n")
@@ -46,7 +47,11 @@ def make_command_file(path_to_debug_info, prefix_code='', no_import=False):
             pass
         else:
             path = os.path.join(path_to_debug_info, "cython_debug", "interpreter")
-        interpreter = open(path).read()
+            interpreter_file = open(path)
+            try:
+                interpreter = interpreter_file.read()
+            finally:
+                interpreter_file.close()
             f.write("file %s\n" % interpreter)
             f.write('\n'.join('cy import %s\n' % fn for fn in debug_files))
             f.write(textwrap.dedent('''\
@@ -62,7 +67,7 @@ def make_command_file(path_to_debug_info, prefix_code='', no_import=False):
 
                 source .cygdbinit
             '''))
-
+    finally:
         f.close()
 
     return tempfilename