cvsps: cvs log loop uses lookahead to avoid misleading text

Changes cvsps.py's cvs log reader to use a one-line lookahead, so
that possibly misleading log messages can be disambiguated.  In
particular I have past committers who used cvs log's 28-character
row of hyphens within commit messages; this throws cvsps and disrupts
conversion.  The only alternative in this case is to edit the cvs
,v file by hand, which bloodies mercurial's "don't change history"
principle.

hgext/convert/cvsps.py

@@ -1,678 +1,684 b''
 #
 # Mercurial built-in replacement for cvsps.
 #
 # Copyright 2008, Frank Kingswood <[e-mail]>
 #
 # This software may be used and distributed according to the terms
 # of the GNU General Public License, incorporated herein by reference.
 
 import os
 import re
 import cPickle as pickle
 from mercurial import util
 from mercurial.i18n import _
 
 def listsort(list, key):
     "helper to sort by key in Python 2.3"
     try:
         list.sort(key=key)
     except TypeError:
         list.sort(lambda l, r: cmp(key(l), key(r)))
 
 class logentry(object):
     '''Class logentry has the following attributes:
         .author    - author name as CVS knows it
         .branch    - name of branch this revision is on
         .branches  - revision tuple of branches starting at this revision
         .comment   - commit message
         .date      - the commit date as a (time, tz) tuple
         .dead      - true if file revision is dead
         .file      - Name of file
         .lines     - a tuple (+lines, -lines) or None
         .parent    - Previous revision of this entry
         .rcs       - name of file as returned from CVS
         .revision  - revision number as tuple
         .tags      - list of tags on the file
     '''
     def __init__(self, **entries):
         self.__dict__.update(entries)
 
 class logerror(Exception):
     pass
 
 def getrepopath(cvspath):
     """Return the repository path from a CVS path.
 
     >>> getrepopath('/foo/bar')
     '/foo/bar'
     >>> getrepopath('c:/foo/bar')
     'c:/foo/bar'
     >>> getrepopath(':pserver:10/foo/bar')
     '/foo/bar'
     >>> getrepopath(':pserver:10c:/foo/bar')
     '/foo/bar'
     >>> getrepopath(':pserver:/foo/bar')
     '/foo/bar'
     >>> getrepopath(':pserver:c:/foo/bar')
     'c:/foo/bar'
     >>> getrepopath(':pserver:[e-mail]:/foo/bar')
     '/foo/bar'
     >>> getrepopath(':pserver:[e-mail]:c:/foo/bar')
     'c:/foo/bar'
     """
     # According to CVS manual, CVS paths are expressed like:
     # [:method:][[user][:password]@]hostname[:[port]]/path/to/repository
     #
     # Unfortunately, Windows absolute paths start with a drive letter
     # like 'c:' making it harder to parse. Here we assume that drive
     # letters are only one character long and any CVS component before
     # the repository path is at least 2 characters long, and use this
     # to disambiguate.
     parts = cvspath.split(':')
     if len(parts) == 1:
         return parts[0]
     # Here there is an ambiguous case if we have a port number
     # immediately followed by a Windows driver letter. We assume this
     # never happens and decide it must be CVS path component,
     # therefore ignoring it.
     if len(parts[-2]) > 1:
         return parts[-1].lstrip('0123456789')
     return parts[-2] + ':' + parts[-1]
 
 def createlog(ui, directory=None, root="", rlog=True, cache=None):
     '''Collect the CVS rlog'''
 
     # Because we store many duplicate commit log messages, reusing strings
     # saves a lot of memory and pickle storage space.
     _scache = {}
     def scache(s):
         "return a shared version of a string"
         return _scache.setdefault(s, s)
 
     ui.status(_('collecting CVS rlog\n'))
 
     log = []      # list of logentry objects containing the CVS state
 
     # patterns to match in CVS (r)log output, by state of use
     re_00 = re.compile('RCS file: (.+)$')
     re_01 = re.compile('cvs \\[r?log aborted\\]: (.+)$')
     re_02 = re.compile('cvs (r?log|server): (.+)\n$')
     re_03 = re.compile("(Cannot access.+CVSROOT)|(can't create temporary directory.+)$")
     re_10 = re.compile('Working file: (.+)$')
     re_20 = re.compile('symbolic names:')
     re_30 = re.compile('\t(.+): ([\\d.]+)$')
     re_31 = re.compile('----------------------------$')
     re_32 = re.compile('=============================================================================$')
     re_50 = re.compile('revision ([\\d.]+)(\s+locked by:\s+.+;)?$')
     re_60 = re.compile(r'date:\s+(.+);\s+author:\s+(.+);\s+state:\s+(.+?);(\s+lines:\s+(\+\d+)?\s+(-\d+)?;)?')
     re_70 = re.compile('branches: (.+);$')
 
     prefix = ''   # leading path to strip of what we get from CVS
 
     if directory is None:
         # Current working directory
 
         # Get the real directory in the repository
         try:
             prefix = file(os.path.join('CVS','Repository')).read().strip()
             if prefix == ".":
                 prefix = ""
             directory = prefix
         except IOError:
             raise logerror('Not a CVS sandbox')
 
         if prefix and not prefix.endswith(os.sep):
             prefix += os.sep
 
         # Use the Root file in the sandbox, if it exists
         try:
             root = file(os.path.join('CVS','Root')).read().strip()
         except IOError:
             pass
 
     if not root:
         root = os.environ.get('CVSROOT', '')
 
     # read log cache if one exists
     oldlog = []
     date = None
 
     if cache:
         cachedir = os.path.expanduser('~/.hg.cvsps')
         if not os.path.exists(cachedir):
             os.mkdir(cachedir)
 
         # The cvsps cache pickle needs a uniquified name, based on the
         # repository location. The address may have all sort of nasties
         # in it, slashes, colons and such. So here we take just the
         # alphanumerics, concatenated in a way that does not mix up the
         # various components, so that
         #    :pserver:user@server:/path
         # and
         #    /pserver/user/server/path
         # are mapped to different cache file names.
         cachefile = root.split(":") + [directory, "cache"]
         cachefile = ['-'.join(re.findall(r'\w+', s)) for s in cachefile if s]
         cachefile = os.path.join(cachedir,
                                  '.'.join([s for s in cachefile if s]))
 
     if cache == 'update':
         try:
             ui.note(_('reading cvs log cache %s\n') % cachefile)
             oldlog = pickle.load(file(cachefile))
             ui.note(_('cache has %d log entries\n') % len(oldlog))
         except Exception, e:
             ui.note(_('error reading cache: %r\n') % e)
 
         if oldlog:
             date = oldlog[-1].date    # last commit date as a (time,tz) tuple
             date = util.datestr(date, '%Y/%m/%d %H:%M:%S %1%2')
 
     # build the CVS commandline
     cmd = ['cvs', '-q']
     if root:
         cmd.append('-d%s' % root)
         p = util.normpath(getrepopath(root))
         if not p.endswith('/'):
             p += '/'
         prefix = p + util.normpath(prefix)
     cmd.append(['log', 'rlog'][rlog])
     if date:
         # no space between option and date string
         cmd.append('-d>%s' % date)
     cmd.append(directory)
 
     # state machine begins here
     tags = {}     # dictionary of revisions on current file with their tags
     state = 0
     store = False # set when a new record can be appended
 
     cmd = [util.shellquote(arg) for arg in cmd]
     ui.note(_("running %s\n") % (' '.join(cmd)))
     ui.debug(_("prefix=%r directory=%r root=%r\n") % (prefix, directory, root))
 
-    for line in util.popen(' '.join(cmd)):
+    pfp = util.popen(' '.join(cmd))
+    peek = pfp.readline()
+    while True:
+        line = peek
+        if line == '':
+            break
+        peek = pfp.readline()
         if line.endswith('\n'):
             line = line[:-1]
         #ui.debug('state=%d line=%r\n' % (state, line))
 
         if state == 0:
             # initial state, consume input until we see 'RCS file'
             match = re_00.match(line)
             if match:
                 rcs = match.group(1)
                 tags = {}
                 if rlog:
                     filename = util.normpath(rcs[:-2])
                     if filename.startswith(prefix):
                         filename = filename[len(prefix):]
                     if filename.startswith('/'):
                         filename = filename[1:]
                     if filename.startswith('Attic/'):
                         filename = filename[6:]
                     else:
                         filename = filename.replace('/Attic/', '/')
                     state = 2
                     continue
                 state = 1
                 continue
             match = re_01.match(line)
             if match:
                 raise Exception(match.group(1))
             match = re_02.match(line)
             if match:
                 raise Exception(match.group(2))
             if re_03.match(line):
                 raise Exception(line)
 
         elif state == 1:
             # expect 'Working file' (only when using log instead of rlog)
             match = re_10.match(line)
             assert match, _('RCS file must be followed by working file')
             filename = util.normpath(match.group(1))
             state = 2
 
         elif state == 2:
             # expect 'symbolic names'
             if re_20.match(line):
                 state = 3
 
         elif state == 3:
             # read the symbolic names and store as tags
             match = re_30.match(line)
             if match:
                 rev = [int(x) for x in match.group(2).split('.')]
 
                 # Convert magic branch number to an odd-numbered one
                 revn = len(rev)
                 if revn > 3 and (revn % 2) == 0 and rev[-2] == 0:
                     rev = rev[:-2] + rev[-1:]
                 rev = tuple(rev)
 
                 if rev not in tags:
                     tags[rev] = []
                 tags[rev].append(match.group(1))
 
             elif re_31.match(line):
                 state = 5
             elif re_32.match(line):
                 state = 0
 
         elif state == 4:
             # expecting '------' separator before first revision
             if re_31.match(line):
                 state = 5
             else:
                 assert not re_32.match(line), _('Must have at least some revisions')
 
         elif state == 5:
             # expecting revision number and possibly (ignored) lock indication
             # we create the logentry here from values stored in states 0 to 4,
             # as this state is re-entered for subsequent revisions of a file.
             match = re_50.match(line)
             assert match, _('expected revision number')
             e = logentry(rcs=scache(rcs), file=scache(filename),
                     revision=tuple([int(x) for x in match.group(1).split('.')]),
                     branches=[], parent=None)
             state = 6
 
         elif state == 6:
             # expecting date, author, state, lines changed
             match = re_60.match(line)
             assert match, _('revision must be followed by date line')
             d = match.group(1)
             if d[2] == '/':
                 # Y2K
                 d = '19' + d
 
             if len(d.split()) != 3:
                 # cvs log dates always in GMT
                 d = d + ' UTC'
             e.date = util.parsedate(d, ['%y/%m/%d %H:%M:%S', '%Y/%m/%d %H:%M:%S', '%Y-%m-%d %H:%M:%S'])
             e.author = scache(match.group(2))
             e.dead = match.group(3).lower() == 'dead'
 
             if match.group(5):
                 if match.group(6):
                     e.lines = (int(match.group(5)), int(match.group(6)))
                 else:
                     e.lines = (int(match.group(5)), 0)
             elif match.group(6):
                 e.lines = (0, int(match.group(6)))
             else:
                 e.lines = None
             e.comment = []
             state = 7
 
         elif state == 7:
             # read the revision numbers of branches that start at this revision
             # or store the commit log message otherwise
             m = re_70.match(line)
             if m:
                 e.branches = [tuple([int(y) for y in x.strip().split('.')])
                                 for x in m.group(1).split(';')]
                 state = 8
-            elif re_31.match(line):
+            elif re_31.match(line) and re_50.match(peek):
                 state = 5
                 store = True
             elif re_32.match(line):
                 state = 0
                 store = True
             else:
                 e.comment.append(line)
 
         elif state == 8:
             # store commit log message
             if re_31.match(line):
                 state = 5
                 store = True
             elif re_32.match(line):
                 state = 0
                 store = True
             else:
                 e.comment.append(line)
 
         if store:
             # clean up the results and save in the log.
             store = False
             e.tags = util.sort([scache(x) for x in tags.get(e.revision, [])])
             e.comment = scache('\n'.join(e.comment))
 
             revn = len(e.revision)
             if revn > 3 and (revn % 2) == 0:
                 e.branch = tags.get(e.revision[:-1], [None])[0]
             else:
                 e.branch = None
 
             log.append(e)
 
             if len(log) % 100 == 0:
                 ui.status(util.ellipsis('%d %s' % (len(log), e.file), 80)+'\n')
 
     listsort(log, key=lambda x:(x.rcs, x.revision))
 
     # find parent revisions of individual files
     versions = {}
     for e in log:
         branch = e.revision[:-1]
         p = versions.get((e.rcs, branch), None)
         if p is None:
             p = e.revision[:-2]
         e.parent = p
         versions[(e.rcs, branch)] = e.revision
 
     # update the log cache
     if cache:
         if log:
             # join up the old and new logs
             listsort(log, key=lambda x:x.date)
 
             if oldlog and oldlog[-1].date >= log[0].date:
                 raise logerror('Log cache overlaps with new log entries,'
                                ' re-run without cache.')
 
             log = oldlog + log
 
             # write the new cachefile
             ui.note(_('writing cvs log cache %s\n') % cachefile)
             pickle.dump(log, file(cachefile, 'w'))
         else:
             log = oldlog
 
     ui.status(_('%d log entries\n') % len(log))
 
     return log
 
 
 class changeset(object):
     '''Class changeset has the following attributes:
         .author    - author name as CVS knows it
         .branch    - name of branch this changeset is on, or None
         .comment   - commit message
         .date      - the commit date as a (time,tz) tuple
         .entries   - list of logentry objects in this changeset
         .parents   - list of one or two parent changesets
         .tags      - list of tags on this changeset
     '''
     def __init__(self, **entries):
         self.__dict__.update(entries)
 
 def createchangeset(ui, log, fuzz=60, mergefrom=None, mergeto=None):
     '''Convert log into changesets.'''
 
     ui.status(_('creating changesets\n'))
 
     # Merge changesets
 
     listsort(log, key=lambda x:(x.comment, x.author, x.branch, x.date))
 
     changesets = []
     files = {}
     c = None
     for i, e in enumerate(log):
 
         # Check if log entry belongs to the current changeset or not.
         if not (c and
                   e.comment == c.comment and
                   e.author == c.author and
                   e.branch == c.branch and
                   ((c.date[0] + c.date[1]) <=
                    (e.date[0] + e.date[1]) <=
                    (c.date[0] + c.date[1]) + fuzz) and
                   e.file not in files):
             c = changeset(comment=e.comment, author=e.author,
                           branch=e.branch, date=e.date, entries=[])
             changesets.append(c)
             files = {}
             if len(changesets) % 100 == 0:
                 t = '%d %s' % (len(changesets), repr(e.comment)[1:-1])
                 ui.status(util.ellipsis(t, 80) + '\n')
 
         c.entries.append(e)
         files[e.file] = True
         c.date = e.date       # changeset date is date of latest commit in it
 
     # Sort files in each changeset
 
     for c in changesets:
         def pathcompare(l, r):
             'Mimic cvsps sorting order'
             l = l.split('/')
             r = r.split('/')
             nl = len(l)
             nr = len(r)
             n = min(nl, nr)
             for i in range(n):
                 if i + 1 == nl and nl < nr:
                     return -1
                 elif i + 1 == nr and nl > nr:
                     return +1
                 elif l[i] < r[i]:
                     return -1
                 elif l[i] > r[i]:
                     return +1
             return 0
         def entitycompare(l, r):
             return pathcompare(l.file, r.file)
 
         c.entries.sort(entitycompare)
 
     # Sort changesets by date
 
     def cscmp(l, r):
         d = sum(l.date) - sum(r.date)
         if d:
             return d
 
         # detect vendor branches and initial commits on a branch
         le = {}
         for e in l.entries:
             le[e.rcs] = e.revision
         re = {}
         for e in r.entries:
             re[e.rcs] = e.revision
 
         d = 0
         for e in l.entries:
             if re.get(e.rcs, None) == e.parent:
                 assert not d
                 d = 1
                 break
 
         for e in r.entries:
             if le.get(e.rcs, None) == e.parent:
                 assert not d
                 d = -1
                 break
 
         return d
 
     changesets.sort(cscmp)
 
     # Collect tags
 
     globaltags = {}
     for c in changesets:
         tags = {}
         for e in c.entries:
             for tag in e.tags:
                 # remember which is the latest changeset to have this tag
                 globaltags[tag] = c
 
     for c in changesets:
         tags = {}
         for e in c.entries:
             for tag in e.tags:
                 tags[tag] = True
         # remember tags only if this is the latest changeset to have it
         c.tags = util.sort([tag for tag in tags if globaltags[tag] is c])
 
     # Find parent changesets, handle {{mergetobranch BRANCHNAME}}
     # by inserting dummy changesets with two parents, and handle
     # {{mergefrombranch BRANCHNAME}} by setting two parents.
 
     if mergeto is None:
         mergeto = r'{{mergetobranch ([-\w]+)}}'
     if mergeto:
         mergeto = re.compile(mergeto)
 
     if mergefrom is None:
         mergefrom = r'{{mergefrombranch ([-\w]+)}}'
     if mergefrom:
         mergefrom = re.compile(mergefrom)
 
     versions = {}    # changeset index where we saw any particular file version
     branches = {}    # changeset index where we saw a branch
     n = len(changesets)
     i = 0
     while i<n:
         c = changesets[i]
 
         for f in c.entries:
             versions[(f.rcs, f.revision)] = i
 
         p = None
         if c.branch in branches:
             p = branches[c.branch]
         else:
             for f in c.entries:
                 p = max(p, versions.get((f.rcs, f.parent), None))
 
         c.parents = []
         if p is not None:
             c.parents.append(changesets[p])
 
         if mergefrom:
             m = mergefrom.search(c.comment)
             if m:
                 m = m.group(1)
                 if m == 'HEAD':
                     m = None
                 if m in branches and c.branch != m:
                     c.parents.append(changesets[branches[m]])
 
         if mergeto:
             m = mergeto.search(c.comment)
             if m:
                 try:
                     m = m.group(1)
                     if m == 'HEAD':
                         m = None
                 except:
                     m = None   # if no group found then merge to HEAD
                 if m in branches and c.branch != m:
                     # insert empty changeset for merge
                     cc = changeset(author=c.author, branch=m, date=c.date,
                             comment='convert-repo: CVS merge from branch %s' % c.branch,
                             entries=[], tags=[], parents=[changesets[branches[m]], c])
                     changesets.insert(i + 1, cc)
                     branches[m] = i + 1
 
                     # adjust our loop counters now we have inserted a new entry
                     n += 1
                     i += 2
                     continue
 
         branches[c.branch] = i
         i += 1
 
     # Number changesets
 
     for i, c in enumerate(changesets):
         c.id = i + 1
 
     ui.status(_('%d changeset entries\n') % len(changesets))
 
     return changesets
 
 
 def debugcvsps(ui, *args, **opts):
     '''Read CVS rlog for current directory or named path in repository, and
     convert the log to changesets based on matching commit log entries and dates.'''
 
     if opts["new_cache"]:
         cache = "write"
     elif opts["update_cache"]:
         cache = "update"
     else:
         cache = None
 
     revisions = opts["revisions"]
 
     try:
         if args:
             log = []
             for d in args:
                 log += createlog(ui, d, root=opts["root"], cache=cache)
         else:
             log = createlog(ui, root=opts["root"], cache=cache)
     except logerror, e:
         ui.write("%r\n"%e)
         return
 
     changesets = createchangeset(ui, log, opts["fuzz"])
     del log
 
     # Print changesets (optionally filtered)
 
     off = len(revisions)
     branches = {}    # latest version number in each branch
     ancestors = {}   # parent branch
     for cs in changesets:
 
         if opts["ancestors"]:
             if cs.branch not in branches and cs.parents and cs.parents[0].id:
                 ancestors[cs.branch] = changesets[cs.parents[0].id-1].branch, cs.parents[0].id
             branches[cs.branch] = cs.id
 
         # limit by branches
         if opts["branches"] and (cs.branch or 'HEAD') not in opts["branches"]:
             continue
 
         if not off:
             # Note: trailing spaces on several lines here are needed to have
             #       bug-for-bug compatibility with cvsps.
             ui.write('---------------------\n')
             ui.write('PatchSet %d \n' % cs.id)
             ui.write('Date: %s\n' % util.datestr(cs.date, '%Y/%m/%d %H:%M:%S %1%2'))
             ui.write('Author: %s\n' % cs.author)
             ui.write('Branch: %s\n' % (cs.branch or 'HEAD'))
             ui.write('Tag%s: %s \n' % (['', 's'][len(cs.tags)>1],
                                   ','.join(cs.tags) or '(none)'))
             if opts["parents"] and cs.parents:
                 if len(cs.parents)>1:
                     ui.write('Parents: %s\n' % (','.join([str(p.id) for p in cs.parents])))
                 else:
                     ui.write('Parent: %d\n' % cs.parents[0].id)
 
             if opts["ancestors"]:
                 b = cs.branch
                 r = []
                 while b:
                     b, c = ancestors[b]
                     r.append('%s:%d:%d' % (b or "HEAD", c, branches[b]))
                 if r:
                     ui.write('Ancestors: %s\n' % (','.join(r)))
 
             ui.write('Log:\n')
             ui.write('%s\n\n' % cs.comment)
             ui.write('Members: \n')
             for f in cs.entries:
                 fn = f.file
                 if fn.startswith(opts["prefix"]):
                     fn = fn[len(opts["prefix"]):]
                 ui.write('\t%s:%s->%s%s \n' % (fn, '.'.join([str(x) for x in f.parent]) or 'INITIAL',
                                           '.'.join([str(x) for x in f.revision]), ['', '(DEAD)'][f.dead]))
             ui.write('\n')
 
         # have we seen the start tag?
         if revisions and off:
             if revisions[0] == str(cs.id) or \
                 revisions[0] in cs.tags:
                 off = False
 
         # see if we reached the end tag
         if len(revisions)>1 and not off:
             if revisions[1] == str(cs.id) or \
                 revisions[1] in cs.tags:
                 break