Bug 1623982 - Fix performance of indented_repr in Python 3 r=ahal

Differential Revision: https://phabricator.services.mozilla.com/D67688

--HG--
extra : moz-landing-system : lando

configure.py

@@ -29,7 +29,7 @@ from mozbuild.configure import (
 from mozbuild.pythonutil import iter_modules_in_path
 from mozbuild.backend.configenvironment import PartialConfigEnvironment
 from mozbuild.util import (
-    indented_repr,
+    write_indented_repr,
 )
 import mozpack.path as mozpath
 import six
@@ -120,7 +120,8 @@ def config_status(config):
             from __future__ import unicode_literals
         ''') % {'python': config['PYTHON']})
         for k, v in six.iteritems(sanitized_config):
-            fh.write('%s = %s\n' % (k, indented_repr(v)))
+            fh.write('%s = ' % k)
+            write_indented_repr(fh, v)
         fh.write("__all__ = ['topobjdir', 'topsrcdir', 'defines', "
                  "'non_global_defines', 'substs', 'mozconfig']")
 

python/mozbuild/mozbuild/test/test_util.py

@@ -5,8 +5,9 @@
 
 from __future__ import absolute_import, print_function, unicode_literals
 
-import itertools
 import hashlib
+import io
+import itertools
 import os
 import unittest
 import six
@@ -21,11 +22,11 @@ from mozbuild.util import (
     expand_variables,
     group_unified_files,
     hash_file,
-    indented_repr,
     memoize,
     memoized_property,
     pair,
     resolve_target_to_make,
+    write_indented_repr,
     MozbuildDeletionError,
     HierarchicalStringList,
     EnumString,
@@ -819,7 +820,7 @@ class TestEnumString(unittest.TestCase):
 
 class TestIndentedRepr(unittest.TestCase):
     @unittest.skipUnless(six.PY2, 'requires Python 2')
-    def test_indented_repr_py2(self):
+    def test_write_indented_repr_py2(self):
         data = textwrap.dedent(r'''
         {
             'a': 1,
@@ -840,14 +841,17 @@ class TestIndentedRepr(unittest.TestCase):
             'pile_of_poo': '💩',
             'special_chars': '\\\'"\x08\n\t',
             'with_accents': 'éàñ',
-        }''').lstrip()
+        }
+        ''').lstrip()
 
         obj = eval(data)
+        buf = io.StringIO()
+        write_indented_repr(buf, obj)
 
-        self.assertEqual(indented_repr(obj), data)
+        self.assertEqual(buf.getvalue(), data)
 
     @unittest.skipUnless(six.PY3, 'requires Python 3')
-    def test_indented_repr(self):
+    def test_write_indented_repr(self):
         data = textwrap.dedent(r'''
         {   b'c': 'xyz',
             'a': 1,
@@ -858,11 +862,14 @@ class TestIndentedRepr(unittest.TestCase):
             'pile_of_bytes': b'\xf0\x9f\x92\xa9',
             'pile_of_poo': '💩',
             'special_chars': '\\\'"\x08\n\t',
-            'with_accents': 'éàñ'}''').lstrip()
+            'with_accents': 'éàñ'}
+        ''').lstrip()
 
         obj = eval(data)
+        buf = six.StringIO()
+        write_indented_repr(buf, obj)
 
-        self.assertEqual(indented_repr(obj), data)
+        self.assertEqual(buf.getvalue(), data)
 
 
 if __name__ == '__main__':

python/mozbuild/mozbuild/util.py

@@ -20,7 +20,6 @@ import os
 import pprint
 import re
 import stat
-import subprocess
 import sys
 import time
 from collections import (
@@ -1297,28 +1296,6 @@ def _escape_char(c):
     return six.text_type(c.encode('unicode_escape'))
 
 
-# The default PrettyPrinter has some issues with UTF-8, so we need to override
-# some stuff here.
-class _PrettyPrinter(pprint.PrettyPrinter):
-    def format(self, object, context, maxlevels, level):
-        if not (isinstance(object, six.text_type) or
-                isinstance(object, six.binary_type)):
-            return super(_PrettyPrinter, self).format(
-                object, context, maxlevels, level)
-        # This is super hacky and weird, but the output of 'repr' actually
-        # varies based on the default I/O encoding of the process, which isn't
-        # necessarily utf-8. Instead we open a new shell and ask what the repr
-        # WOULD be assuming the default encoding is utf-8. If you can come up
-        # with a better way of doing this without simply re-implementing the
-        # logic of "repr", please replace this.
-        env = dict(os.environ)
-        env['PYTHONIOENCODING'] = 'utf-8'
-        ret = six.ensure_text(subprocess.check_output(
-            [sys.executable], input='print(repr(%s))' % repr(object),
-            universal_newlines=True, env=env, encoding='utf-8')).strip()
-        return (ret, True, False)
-
-
 if six.PY2:  # Delete when we get rid of Python 2.
     # Mapping table between raw characters below \x80 and their escaped
     # counterpart, when they differ
@@ -1333,14 +1310,16 @@ if six.PY2:  # Delete when we get rid of Python 2.
         '([' + ''.join(_INDENTED_REPR_TABLE.values()) + ']+)')
 
 
-def indented_repr(o, indent=4):
-    '''Similar to repr(), but returns an indented representation of the object
+def write_indented_repr(f, o, indent=4):
+    '''Write an indented representation (similar to repr()) of the object to the
+    given file `f`.
 
     One notable difference with repr is that the returned representation
     assumes `from __future__ import unicode_literals`.
     '''
     if six.PY3:
-        return _PrettyPrinter(indent=indent).pformat(o)
+        pprint.pprint(o, stream=f, indent=indent)
+        return
     # Delete everything below when we get rid of Python 2.
     one_indent = ' ' * indent
 
@@ -1382,7 +1361,8 @@ def indented_repr(o, indent=4):
             yield ']'
         else:
             yield repr(o)
-    return ''.join(recurse_indented_repr(o, 0))
+    result = ''.join(recurse_indented_repr(o, 0)) + '\n'
+    f.write(result)
 
 
 def patch_main():