D2868: util: prefer "bytesio" to "stringio"

[indygreg (Gregory Szorc)]

indygreg created this revision.
Herald added a subscriber: mercurial-devel.
Herald added a reviewer: hg-reviewers.

REVISION SUMMARY
  The io.BytesIO and io.StringIO types enforce the type of
  data being operated on. On Python 2, we use cStringIO.StringIO(),
  which is lax about mixing types. On Python 3, we actually use
  io.BytesIO. Ideally, we'd use io.BytesIO on Python 2. But I believe
  its performance is poor compared to cString.StringIO().
  
  Anyway, we canonically define our pycompat type as "stringio."
  That name is misleading, especially on Python 3.
  
  This commit renames the canonical symbols to "bytesio."
  "stringio" is preserved as an alias for API compatibility. There
  are a lot of callers in the repo and I hesitate to take away the
  old name. I also don't feel like changing everything at this time.
  But at least new callers can use a "proper" name.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D2868

AFFECTED FILES
  mercurial/pure/mpatch.py
  mercurial/pure/parsers.py
  mercurial/pycompat.py
  mercurial/util.py

CHANGE DETAILS

diff --git a/mercurial/util.py b/mercurial/util.py
--- a/mercurial/util.py
+++ b/mercurial/util.py
@@ -71,7 +71,9 @@
 stderr = pycompat.stderr
 stdin = pycompat.stdin
 stdout = pycompat.stdout
-stringio = pycompat.stringio
+bytesio = pycompat.bytesio
+# TODO deprecate stringio name, as it is a lie on Python 3.
+stringio = bytesio
 xmlrpclib = pycompat.xmlrpclib
 
 httpserver = urllibcompat.httpserver
diff --git a/mercurial/pycompat.py b/mercurial/pycompat.py
--- a/mercurial/pycompat.py
+++ b/mercurial/pycompat.py
@@ -64,7 +64,9 @@
     sysexecutable = sys.executable
     if sysexecutable:
         sysexecutable = os.fsencode(sysexecutable)
-    stringio = io.BytesIO
+    bytesio = io.BytesIO
+    # TODO deprecate stringio name, as it is a lie on Python 3.
+    stringio = bytesio
 
     def maplist(*args):
         return list(map(*args))
@@ -343,7 +345,8 @@
     getcwd = os.getcwd
     sysexecutable = sys.executable
     shlexsplit = shlex.split
-    stringio = cStringIO.StringIO
+    bytesio = cStringIO.StringIO
+    stringio = bytesio
     maplist = map
     ziplist = zip
     rawinput = raw_input
diff --git a/mercurial/pure/parsers.py b/mercurial/pure/parsers.py
--- a/mercurial/pure/parsers.py
+++ b/mercurial/pure/parsers.py
@@ -12,7 +12,7 @@
 
 from ..node import nullid
 from .. import pycompat
-stringio = pycompat.stringio
+stringio = pycompat.bytesio
 
 
 _pack = struct.pack
diff --git a/mercurial/pure/mpatch.py b/mercurial/pure/mpatch.py
--- a/mercurial/pure/mpatch.py
+++ b/mercurial/pure/mpatch.py
@@ -10,7 +10,7 @@
 import struct
 
 from .. import pycompat
-stringio = pycompat.stringio
+stringio = pycompat.bytesio
 
 class mpatchError(Exception):
     """error raised when a delta cannot be decoded



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