hgext: more patchbomb documentation

+ Add a description of how to enable this extension

+ Note which command it provides (it's not very easy to guess
  that "hgext.patchbomb" enables the "email" command, unless one
  can read Python sources)

+ Expand the descriptions of the -n and -m options of "hg email".

+ Mention that formail is (commonly) part of the procmail package.

hgext/patchbomb.py

@@ -1,309 +1,332 b''
 # Command for sending a collection of Mercurial changesets as a series
 # of patch emails.
 #
 # The series is started off with a "[PATCH 0 of N]" introduction,
 # which describes the series as a whole.
 #
 # Each patch email has a Subject line of "[PATCH M of N] ...", using
 # the first line of the changeset description as the subject text.
 # The message contains two or three body parts:
 #
 #   The remainder of the changeset description.
 #
 #   [Optional] If the diffstat program is installed, the result of
 #   running diffstat on the patch.
 #
 #   The patch itself, as generated by "hg export".
 #
 # Each message refers to all of its predecessors using the In-Reply-To
 # and References headers, so they will show up as a sequence in
 # threaded mail and news readers, and in mail archives.
 #
 # For each changeset, you will be prompted with a diffstat summary and
 # the changeset summary, so you can be sure you are sending the right
 # changes.
 #
-# It is best to run this script with the "-n" (test only) flag before
-# firing it up "for real", in which case it will use your pager to
-# display each of the messages that it would send.
+# To enable this extension:
 #
-# The "-m" (mbox) option will create an mbox file instead of sending
-# the messages directly. This can be reviewed e.g. with "mutt -R -f mbox",
-# and finally sent with "formail -s sendmail -bm -t < mbox".
+#   [extensions]
+#   hgext.patchbomb =
 #
 # To configure other defaults, add a section like this to your hgrc
 # file:
 #
-# [email]
-# from = My Name <my@email>
-# to = recipient1, recipient2, ...
-# cc = cc1, cc2, ...
-# bcc = bcc1, bcc2, ...
+#   [email]
+#   from = My Name <my@email>
+#   to = recipient1, recipient2, ...
+#   cc = cc1, cc2, ...
+#   bcc = bcc1, bcc2, ...
+#
+# Then you can use the "hg email" command to mail a series of changesets
+# as a patchbomb.
+#
+# To avoid sending patches prematurely, it is a good idea to first run
+# the "email" command with the "-n" option (test only).  You will be
+# prompted for an email recipient address, a subject an an introductory
+# message describing the patches of your patchbomb.  Then when all is
+# done, your pager will be fired up once for each patchbomb message, so
+# you can verify everything is alright.
+#
+# The "-m" (mbox) option is also very useful.  Instead of previewing
+# each patchbomb message in a pager or sending the messages directly,
+# it will create a UNIX mailbox file with the patch emails.  This
+# mailbox file can be previewed with any mail user agent which supports
+# UNIX mbox files, i.e. with mutt:
+#
+#   % mutt -R -f mbox
+#
+# When you are previewing the patchbomb messages, you can use `formail'
+# (a utility that is commonly installed as part of the procmail package),
+# to send each message out:
+#
+#  % formail -s sendmail -bm -t < mbox
+#
+# That should be all.  Now your patchbomb is on its way out.
 
 from mercurial.demandload import *
 demandload(globals(), '''email.MIMEMultipart email.MIMEText email.Utils
                          mercurial:commands,hg,ui
                          os errno popen2 socket sys tempfile time''')
 from mercurial.i18n import gettext as _
 from mercurial.node import *
 
 try:
     # readline gives raw_input editing capabilities, but is not
     # present on windows
     import readline
 except ImportError: pass
 
 def diffstat(patch):
     fd, name = tempfile.mkstemp(prefix="hg-patchbomb-", suffix=".txt")
     try:
         p = popen2.Popen3('diffstat -p1 -w79 2>/dev/null > ' + name)
         try:
             for line in patch: print >> p.tochild, line
             p.tochild.close()
             if p.wait(): return
             fp = os.fdopen(fd, 'r')
             stat = []
             for line in fp: stat.append(line.lstrip())
             last = stat.pop()
             stat.insert(0, last)
             stat = ''.join(stat)
             if stat.startswith('0 files'): raise ValueError
             return stat
         except: raise
     finally:
         try: os.unlink(name)
         except: pass
 
 def patchbomb(ui, repo, *revs, **opts):
     '''send changesets as a series of patch emails
 
     The series starts with a "[PATCH 0 of N]" introduction, which
     describes the series as a whole.
 
     Each patch email has a Subject line of "[PATCH M of N] ...", using
     the first line of the changeset description as the subject text.
     The message contains two or three body parts.  First, the rest of
     the changeset description.  Next, (optionally) if the diffstat
     program is installed, the result of running diffstat on the patch.
     Finally, the patch itself, as generated by "hg export".'''
     def prompt(prompt, default = None, rest = ': ', empty_ok = False):
         if default: prompt += ' [%s]' % default
         prompt += rest
         while True:
             r = raw_input(prompt)
             if r: return r
             if default is not None: return default
             if empty_ok: return r
             ui.warn(_('Please enter a valid value.\n'))
 
     def confirm(s):
         if not prompt(s, default = 'y', rest = '? ').lower().startswith('y'):
             raise ValueError
 
     def cdiffstat(summary, patch):
         s = diffstat(patch)
         if s:
             if summary:
                 ui.write(summary, '\n')
                 ui.write(s, '\n')
             confirm(_('Does the diffstat above look okay'))
         return s
 
     def makepatch(patch, idx, total):
         desc = []
         node = None
         body = ''
         for line in patch:
             if line.startswith('#'):
                 if line.startswith('# Node ID'): node = line.split()[-1]
                 continue
             if line.startswith('diff -r'): break
             desc.append(line)
         if not node: raise ValueError
 
         #body = ('\n'.join(desc[1:]).strip() or
         #        'Patch subject is complete summary.')
         #body += '\n\n\n'
 
         if opts['plain']:
             while patch and patch[0].startswith('# '): patch.pop(0)
             if patch: patch.pop(0)
             while patch and not patch[0].strip(): patch.pop(0)
         if opts['diffstat']:
             body += cdiffstat('\n'.join(desc), patch) + '\n\n'
         if opts['attach']:
             msg = email.MIMEMultipart.MIMEMultipart()
             if body: msg.attach(email.MIMEText.MIMEText(body, 'plain'))
             p = email.MIMEText.MIMEText('\n'.join(patch), 'x-patch')
             binnode = bin(node)
             # if node is mq patch, it will have patch file name as tag
             patchname = [t for t in repo.nodetags(binnode)
                          if t.endswith('.patch') or t.endswith('.diff')]
             if patchname:
                 patchname = patchname[0]
             elif total > 1:
                 patchname = commands.make_filename(repo, '%b-%n.patch',
                                                    binnode, idx, total)
             else:
                 patchname = commands.make_filename(repo, '%b.patch', binnode)
             p['Content-Disposition'] = 'inline; filename=' + patchname
             msg.attach(p)
         else:
             body += '\n'.join(patch)
             msg = email.MIMEText.MIMEText(body)
         if total == 1:
             subj = '[PATCH] ' + desc[0].strip()
         else:
             subj = '[PATCH %d of %d] %s' % (idx, total, desc[0].strip())
         if subj.endswith('.'): subj = subj[:-1]
         msg['Subject'] = subj
         msg['X-Mercurial-Node'] = node
         return msg
 
     start_time = int(time.time())
 
     def genmsgid(id):
         return '<%s.%s@%s>' % (id[:20], start_time, socket.getfqdn())
 
     patches = []
 
     class exportee:
         def __init__(self, container):
             self.lines = []
             self.container = container
             self.name = 'email'
 
         def write(self, data):
             self.lines.append(data)
 
         def close(self):
             self.container.append(''.join(self.lines).split('\n'))
             self.lines = []
 
     commands.export(ui, repo, *revs, **{'output': exportee(patches),
                                         'switch_parent': False,
                                         'text': None})
 
     jumbo = []
     msgs = []
 
     ui.write(_('This patch series consists of %d patches.\n\n') % len(patches))
 
     for p, i in zip(patches, range(len(patches))):
         jumbo.extend(p)
         msgs.append(makepatch(p, i + 1, len(patches)))
 
     sender = (opts['from'] or ui.config('email', 'from') or
               ui.config('patchbomb', 'from') or
               prompt('From', ui.username()))
 
     def getaddrs(opt, prpt, default = None):
         addrs = opts[opt] or (ui.config('email', opt) or
                               ui.config('patchbomb', opt) or
                               prompt(prpt, default = default)).split(',')
         return [a.strip() for a in addrs if a.strip()]
     to = getaddrs('to', 'To')
     cc = getaddrs('cc', 'Cc', '')
 
     bcc = opts['bcc'] or (ui.config('email', 'bcc') or
                           ui.config('patchbomb', 'bcc') or '').split(',')
     bcc = [a.strip() for a in bcc if a.strip()]
 
     if len(patches) > 1:
         ui.write(_('\nWrite the introductory message for the patch series.\n\n'))
 
         subj = '[PATCH 0 of %d] %s' % (
             len(patches),
             opts['subject'] or
             prompt('Subject:', rest = ' [PATCH 0 of %d] ' % len(patches)))
 
         ui.write(_('Finish with ^D or a dot on a line by itself.\n\n'))
 
         body = []
 
         while True:
             try: l = raw_input()
             except EOFError: break
             if l == '.': break
             body.append(l)
 
         if opts['diffstat']:
             d = cdiffstat(_('Final summary:\n'), jumbo)
             if d: body.append('\n' + d)
 
         body = '\n'.join(body) + '\n'
 
         msg = email.MIMEText.MIMEText(body)
         msg['Subject'] = subj
 
         msgs.insert(0, msg)
 
     ui.write('\n')
 
     if not opts['test'] and not opts['mbox']:
         mailer = mail.connect(ui)
     parent = None
 
     # Calculate UTC offset
     if time.daylight: offset = time.altzone
     else: offset = time.timezone
     if offset <= 0: sign, offset = '+', -offset
     else: sign = '-'
     offset = '%s%02d%02d' % (sign, offset / 3600, (offset % 3600) / 60)
 
     sender_addr = email.Utils.parseaddr(sender)[1]
     for m in msgs:
         try:
             m['Message-Id'] = genmsgid(m['X-Mercurial-Node'])
         except TypeError:
             m['Message-Id'] = genmsgid('patchbomb')
         if parent:
             m['In-Reply-To'] = parent
         else:
             parent = m['Message-Id']
         m['Date'] = time.strftime("%a, %d %b %Y %H:%M:%S", time.localtime(start_time)) + ' ' + offset
 
         start_time += 1
         m['From'] = sender
         m['To'] = ', '.join(to)
         if cc: m['Cc']  = ', '.join(cc)
         if bcc: m['Bcc'] = ', '.join(bcc)
         if opts['test']:
             ui.status('Displaying ', m['Subject'], ' ...\n')
             fp = os.popen(os.getenv('PAGER', 'more'), 'w')
             try:
                 fp.write(m.as_string(0))
                 fp.write('\n')
             except IOError, inst:
                 if inst.errno != errno.EPIPE:
                     raise
             fp.close()
         elif opts['mbox']:
             ui.status('Writing ', m['Subject'], ' ...\n')
             fp = open(opts['mbox'], m.has_key('In-Reply-To') and 'ab+' or 'wb+')
             date = time.asctime(time.localtime(start_time))
             fp.write('From %s %s\n' % (sender_addr, date))
             fp.write(m.as_string(0))
             fp.write('\n\n')
             fp.close()
         else:
             ui.status('Sending ', m['Subject'], ' ...\n')
             # Exim does not remove the Bcc field
             del m['Bcc']
             mailer.sendmail(sender, to + bcc + cc, m.as_string(0))
 
 cmdtable = {
     'email':
     (patchbomb,
      [('a', 'attach', None, 'send patches as inline attachments'),
       ('', 'bcc', [], 'email addresses of blind copy recipients'),
       ('c', 'cc', [], 'email addresses of copy recipients'),
       ('d', 'diffstat', None, 'add diffstat output to messages'),
       ('f', 'from', '', 'email address of sender'),
       ('', 'plain', None, 'omit hg patch header'),
       ('n', 'test', None, 'print messages that would be sent'),
       ('m', 'mbox', '', 'write messages to mbox file instead of sending them'),
       ('s', 'subject', '', 'subject of introductory message'),
       ('t', 'to', [], 'email addresses of recipients')],
      "hg email [OPTION]... [REV]...")
     }