[jhbuild] hg: Port to Python 3

[Christoph Reiter <creiter src gnome org>]

commit c9a80e57aaeb8576fa2d861fc096162eed1bd856
Author: Christoph Reiter <reiter christoph gmail com>
Date:   Sat Oct 19 10:41:14 2019 +0200

    hg: Port to Python 3
    
    Use sys.executable to run hg-update.py with the current interpreter.
    Decode output of external commands everywhere to get the same result
    with py2/3.
    
    Change the hg-update.py shebang to python3 for Debian's linitan.
    
    Fixes #39

 jhbuild/versioncontrol/hg.py | 7 ++++---
 scripts/hg-update.py         | 6 +++---
 2 files changed, 7 insertions(+), 6 deletions(-)
---
diff --git a/jhbuild/versioncontrol/hg.py b/jhbuild/versioncontrol/hg.py
index a9406ca7..6e79b4e6 100644
--- a/jhbuild/versioncontrol/hg.py
+++ b/jhbuild/versioncontrol/hg.py
@@ -22,11 +22,12 @@ __all__ = []
 __metaclass__ = type
 
 import os
+import sys
 from subprocess import Popen, PIPE
 
 from jhbuild.errors import FatalError, CommandError
 from jhbuild.versioncontrol import Repository, Branch, register_repo_type
-from jhbuild.utils import inpath, _, urlutils
+from jhbuild.utils import inpath, _, urlutils, udecode
 
 class HgRepository(Repository):
     """A class representing a Mercurial repository.
@@ -97,7 +98,7 @@ class HgBranch(Branch):
         else:
             hg_update_path = os.path.join(PKGDATADIR, 'hg-update.py')
         hg_update_path = os.path.normpath(hg_update_path)
-        buildscript.execute([hg_update_path], 'hg', cwd=self.srcdir)
+        buildscript.execute([sys.executable, hg_update_path], 'hg', cwd=self.srcdir)
 
     def checkout(self, buildscript):
         if not inpath('hg', os.environ['PATH'].split(os.pathsep)):
@@ -111,7 +112,7 @@ class HgBranch(Branch):
                        cwd=self.srcdir)
         except OSError as e:
             raise CommandError(str(e))
-        return hg.stdout.read().strip()
+        return udecode(hg.stdout.read()).strip()
 
     def tree_id(self):
         if not os.path.exists(self.srcdir):
diff --git a/scripts/hg-update.py b/scripts/hg-update.py
index 80cf8f6e..64c66396 100755
--- a/scripts/hg-update.py
+++ b/scripts/hg-update.py
@@ -1,4 +1,4 @@
-#! /usr/bin/env python2
+#! /usr/bin/env python3
 #
 # hg-update - pull and update a mercurial repository
 #
@@ -27,7 +27,7 @@ import re
 from subprocess import Popen, call, PIPE, STDOUT
 
 def get_parent():
-    hg = Popen(['hg', 'parents', '--template', '{rev}'], stdout=PIPE)
+    hg = Popen(['hg', 'parents', '--template', '{rev}'], stdout=PIPE, universal_newlines=True)
     try:
         return hg.stdout.read().split()[0]
     except IndexError:
@@ -43,7 +43,7 @@ def update():
     env['HGMERGE'] = '/bin/false'
     env['LANG'] = 'C'
     hg = Popen(['hg', 'update', '--noninteractive'], stdout=PIPE,
-               stderr=STDOUT, env=env)
+               stderr=STDOUT, env=env, universal_newlines=True)
     out = hg.communicate()[0]
     if hg.returncode != 0:
         # Use CVS-like format for conflicts.