view hgext3rd/topic/common.py @ 6935:954d7ea5cd67 stable

stack: when stack base is obsolete, pick any successor, even if at random

There are situations when s0 is obsolete and we also cannot pick just one
successor for it to use in stack. In such a case, let's pick the "latest"
successor from the first set.

We're assuming that obsutil.successorssets() returns data in the same order (it
should, since it makes sure to sort data internally). Keeping that in mind,
while the successor picked for s0 by this code is not based on any sort of
sophisticated logic, it should nonetheless be the same every time.

This patch is probably not going to completely break anything that was
previously working fine, because the previous behavior was to just abort with
an exception.

# Copyright 2019 Pierre-Yves David <[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.

def hastopicext(repo):
    """True if the repo use the topic extension"""
    return getattr(repo, 'hastopicext', False)

def parsefqbn(string):
    """parse branch//namespace/topic string into branch, namespace and topic

    >>> parsefqbn(b'branch//topic')
    ('branch', 'none', 'topic')
    >>> parsefqbn(b'//namespace/topic')
    ('default', 'namespace', 'topic')
    >>> parsefqbn(b'branch//')
    ('branch', 'none', '')
    >>> parsefqbn(b'//namespace/')
    ('default', 'namespace', '')
    >>> parsefqbn(b'/topic')
    ('/topic', 'none', '')
    >>> parsefqbn(b'//topic')
    ('default', 'none', 'topic')
    >>> parsefqbn(b'branch//namespace/topic')
    ('branch', 'namespace', 'topic')
    >>> parsefqbn(b'file:///tmp/branch//')
    ('file:///tmp/branch', 'none', '')
    >>> parsefqbn(b'http://example.com/branch//namespace/topic')
    ('http://example.com/branch', 'namespace', 'topic')
    """
    branch, sep, other = string.rpartition(b'//')
    if not sep:
        # when there's no // anywhere in the string, rpartition returns
        # untouched string as the 3rd element, and the first two are empty
        branch, other = other, b''
    if not branch:
        branch = b'default'
    tns, sep, topic = other.partition(b'/')
    if not sep:
        # when there's no / in the rest of the string, there can only be topic
        tns, topic = b'none', tns
    return branch, tns, topic

def formatfqbn(branch=b'', namespace=b'', topic=b'', short=True):
    """format branch, namespace and topic into branch//namespace/topic string

    >>> formatfqbn(branch=b'branch', topic=b'topic')
    'branch//topic'
    >>> formatfqbn(namespace=b'namespace', topic=b'topic')
    '//namespace/topic'
    >>> formatfqbn(branch=b'branch')
    'branch'
    >>> formatfqbn(branch=b'branch//')
    'branch////'
    >>> formatfqbn(branch=b'double//slash')
    'double//slash//'
    >>> formatfqbn(namespace=b'namespace')
    '//namespace/'
    >>> formatfqbn(branch=b'/topic')
    '/topic'
    >>> formatfqbn(topic=b'topic')
    '//topic'
    >>> formatfqbn(branch=b'branch', namespace=b'namespace', topic=b'topic')
    'branch//namespace/topic'
    >>> formatfqbn(branch=b'foo/bar', namespace=b'user26', topic=b'feature')
    'foo/bar//user26/feature'
    >>> formatfqbn(branch=b'http://example.com/branch', namespace=b'namespace', topic=b'topic')
    'http://example.com/branch//namespace/topic'
    """
    result = b''
    showbranch = True # branch and not (short and branch == b'default')
    shownamespace = namespace and not (short and namespace == b'none')
    if short and not showbranch and not shownamespace and not topic:
        # if there's nothing to show, show at least branch
        showbranch = True
    if showbranch:
        result += branch
    if shownamespace or topic or b'//' in branch:
        result += b'//'
    if shownamespace:
        result += namespace + b'/'
    result += topic
    return result

def upgradeformat(branch):
    """take branch and topic in ":" format and return fqbn in "//" format

    This function can be used for transforming branchmap contents of peers that
    don't support topic namespaces yet to work with peers with topic namespaces
    support.

    >>> upgradeformat(b'branch')
    'branch'
    >>> upgradeformat(b'branch:topic')
    'branch//topic'
    >>> upgradeformat(b'branch//')
    'branch////'
    >>> upgradeformat(b'branch//:topic')
    'branch////topic'
    """
    if b':' not in branch:
        # formatting anyway, because named branch could contain "//"
        return formatfqbn(branch=branch)
    # topic namespace cannot be extracted from ":" format
    branch, topic = branch.split(b':', 1)
    return formatfqbn(branch=branch, topic=topic)