generate-churning-bundle: fix script for python3

This script has apparently not run for a long time.

tests/artifacts/scripts/generate-churning-bundle.py

@@ -1,142 +1,142 b''
 #!/usr/bin/env python3
 #
 # generate-branchy-bundle - generate a branch for a "large" branchy repository
 #
 # Copyright 2018 Octobus, [e-mail]
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 #
 # This script generates a repository suitable for testing delta computation
 # strategies.
 #
 # The repository update a single "large" file with many updates. One fixed part
 # of the files always get updated while the rest of the lines get updated over
 # time. This update happens over many topological branches, some getting merged
 # back.
 #
 # Running with `chg` in your path and `CHGHG` set is recommended for speed.
 
 
 import hashlib
 import os
 import shutil
 import subprocess
 import sys
 import tempfile
 
 BUNDLE_NAME = 'big-file-churn.hg'
 
 # constants for generating the repository
 NB_CHANGESET = 5000
 PERIOD_MERGING = 8
 PERIOD_BRANCHING = 7
 MOVE_BACK_MIN = 3
 MOVE_BACK_RANGE = 5
 
 # constants for generating the large file we keep updating
 #
 # At each revision, the beginning on the file change,
 # and set of other lines changes too.
 FILENAME = 'SPARSE-REVLOG-TEST-FILE'
 NB_LINES = 10500
 ALWAYS_CHANGE_LINES = 500
 OTHER_CHANGES = 300
 
 
 def nextcontent(previous_content):
     """utility to produce a new file content from the previous one"""
-    return hashlib.md5(previous_content).hexdigest()
+    return hashlib.md5(previous_content).hexdigest().encode('ascii')
 
 
 def filecontent(iteridx, oldcontent):
     """generate a new file content
 
     The content is generated according the iteration index and previous
     content"""
 
     # initial call
     if iteridx is None:
-        current = ''
+        current = b''
     else:
-        current = str(iteridx)
+        current = b"%d" % iteridx
 
     for idx in range(NB_LINES):
         do_change_line = True
         if oldcontent is not None and ALWAYS_CHANGE_LINES < idx:
             do_change_line = not ((idx - iteridx) % OTHER_CHANGES)
 
         if do_change_line:
-            to_write = current + '\n'
+            to_write = current + b'\n'
             current = nextcontent(current)
         else:
             to_write = oldcontent[idx]
         yield to_write
 
 
 def updatefile(filename, idx):
     """update <filename> to be at appropriate content for iteration <idx>"""
     existing = None
     if idx is not None:
         with open(filename, 'rb') as old:
             existing = old.readlines()
     with open(filename, 'wb') as target:
         for line in filecontent(idx, existing):
             target.write(line)
 
 
 def hg(command, *args):
     """call a mercurial command with appropriate config and argument"""
     env = os.environ.copy()
     if 'CHGHG' in env:
         full_cmd = ['chg']
     else:
         full_cmd = ['hg']
     full_cmd.append('--quiet')
     full_cmd.append(command)
     if command == 'commit':
         # reproducible commit metadata
         full_cmd.extend(['--date', '0 0', '--user', 'test'])
     elif command == 'merge':
         # avoid conflicts by picking the local variant
         full_cmd.extend(['--tool', ':merge-local'])
     full_cmd.extend(args)
     env['HGRCPATH'] = ''
     return subprocess.check_call(full_cmd, env=env)
 
 
 def run(target):
     tmpdir = tempfile.mkdtemp(prefix='tmp-hg-test-big-file-bundle-')
     try:
         os.chdir(tmpdir)
         hg('init')
         updatefile(FILENAME, None)
         hg('commit', '--addremove', '--message', 'initial commit')
         for idx in range(1, NB_CHANGESET + 1):
             if sys.stdout.isatty():
                 print("generating commit #%d/%d" % (idx, NB_CHANGESET))
             if (idx % PERIOD_BRANCHING) == 0:
                 move_back = MOVE_BACK_MIN + (idx % MOVE_BACK_RANGE)
                 hg('update', ".~%d" % move_back)
             if (idx % PERIOD_MERGING) == 0:
                 hg('merge', 'min(head())')
             updatefile(FILENAME, idx)
             hg('commit', '--message', 'commit #%d' % idx)
         hg('bundle', '--all', target, '--config', 'devel.bundle.delta=p1')
         with open(target, 'rb') as bundle:
             data = bundle.read()
             digest = hashlib.md5(data).hexdigest()
         with open(target + '.md5', 'wb') as md5file:
-            md5file.write(digest + '\n')
+            md5file.write(digest.encode('ascii') + b'\n')
         if sys.stdout.isatty():
             print('bundle generated at "%s" md5: %s' % (target, digest))
 
     finally:
         shutil.rmtree(tmpdir)
     return 0
 
 
 if __name__ == '__main__':
     orig = os.path.realpath(os.path.dirname(sys.argv[0]))
     target = os.path.join(orig, os.pardir, 'cache', BUNDLE_NAME)
     sys.exit(run(target))