diff mercurial/filemerge.py @ 33499:0407a51b9d8c

codemod: register core configitems using a script

This is done by a script [2] using RedBaron [1], a tool designed for doing
code refactoring. All "default" values are decided by the script and are
strongly consistent with the existing code.

There are 2 changes done manually to fix tests:

  [warn] mercurial/exchange.py: experimental.bundle2-output-capture: default needs manual removal
  [warn] mercurial/localrepo.py: experimental.hook-track-tags: default needs manual removal

Since RedBaron is not confident about how to indent things [2].

[1]: https://github.com/PyCQA/redbaron
[2]: https://github.com/PyCQA/redbaron/issues/100
[3]:

#!/usr/bin/env python
# codemod_configitems.py - codemod tool to fill configitems
#
# Copyright 2017 Facebook, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from __future__ import absolute_import, print_function

import os
import sys

import redbaron

def readpath(path):
    with open(path) as f:
        return f.read()

def writepath(path, content):
    with open(path, 'w') as f:
        f.write(content)

_configmethods = {'config', 'configbool', 'configint', 'configbytes',
                  'configlist', 'configdate'}

def extractstring(rnode):
    """get the string from a RedBaron string or call_argument node"""
    while rnode.type != 'string':
        rnode = rnode.value
    return rnode.value[1:-1]  # unquote, "'str'" -> "str"

def uiconfigitems(red):
    """match *.ui.config* pattern, yield (node, method, args, section, name)"""
    for node in red.find_all('atomtrailers'):
        entry = None
        try:
            obj = node[-3].value
            method = node[-2].value
            args = node[-1]
            section = args[0].value
            name = args[1].value
            if (obj in ('ui', 'self') and method in _configmethods
                and section.type == 'string' and name.type == 'string'):
                entry = (node, method, args, extractstring(section),
                         extractstring(name))
        except Exception:
            pass
        else:
            if entry:
                yield entry

def coreconfigitems(red):
    """match coreconfigitem(...) pattern, yield (node, args, section, name)"""
    for node in red.find_all('atomtrailers'):
        entry = None
        try:
            args = node[1]
            section = args[0].value
            name = args[1].value
            if (node[0].value == 'coreconfigitem' and section.type == 'string'
                and name.type == 'string'):
                entry = (node, args, extractstring(section),
                         extractstring(name))
        except Exception:
            pass
        else:
            if entry:
                yield entry

def registercoreconfig(cfgred, section, name, defaultrepr):
    """insert coreconfigitem to cfgred AST

    section and name are plain string, defaultrepr is a string
    """
    # find a place to insert the "coreconfigitem" item
    entries = list(coreconfigitems(cfgred))
    for node, args, nodesection, nodename in reversed(entries):
        if (nodesection, nodename) < (section, name):
            # insert after this entry
            node.insert_after(
                'coreconfigitem(%r, %r,\n'
                '    default=%s,\n'
                ')' % (section, name, defaultrepr))
            return

def main(argv):
    if not argv:
        print('Usage: codemod_configitems.py FILES\n'
              'For example, FILES could be "{hgext,mercurial}/*/**.py"')
    dirname = os.path.dirname
    reporoot = dirname(dirname(dirname(os.path.abspath(__file__))))

    # register configitems to this destination
    cfgpath = os.path.join(reporoot, 'mercurial', 'configitems.py')
    cfgred = redbaron.RedBaron(readpath(cfgpath))

    # state about what to do
    registered = set((s, n) for n, a, s, n in coreconfigitems(cfgred))
    toregister = {} # {(section, name): defaultrepr}
    coreconfigs = set() # {(section, name)}, whether it's used in core

    # first loop: scan all files before taking any action
    for i, path in enumerate(argv):
        print('(%d/%d) scanning %s' % (i + 1, len(argv), path))
        iscore = ('mercurial' in path) and ('hgext' not in path)
        red = redbaron.RedBaron(readpath(path))
        # find all repo.ui.config* and ui.config* calls, and collect their
        # section, name and default value information.
        for node, method, args, section, name in uiconfigitems(red):
            if section == 'web':
                # [web] section has some weirdness, ignore them for now
                continue
            defaultrepr = None
            key = (section, name)
            if len(args) == 2:
                if key in registered:
                    continue
                if method == 'configlist':
                    defaultrepr = 'list'
                elif method == 'configbool':
                    defaultrepr = 'False'
                else:
                    defaultrepr = 'None'
            elif len(args) >= 3 and (args[2].target is None or
                                     args[2].target.value == 'default'):
                # try to understand the "default" value
                dnode = args[2].value
                if dnode.type == 'name':
                    if dnode.value in {'None', 'True', 'False'}:
                        defaultrepr = dnode.value
                elif dnode.type == 'string':
                    defaultrepr = repr(dnode.value[1:-1])
                elif dnode.type in ('int', 'float'):
                    defaultrepr = dnode.value
            # inconsistent default
            if key in toregister and toregister[key] != defaultrepr:
                defaultrepr = None
            # interesting to rewrite
            if key not in registered:
                if defaultrepr is None:
                    print('[note] %s: %s.%s: unsupported default'
                          % (path, section, name))
                    registered.add(key) # skip checking it again
                else:
                    toregister[key] = defaultrepr
                    if iscore:
                        coreconfigs.add(key)

    # second loop: rewrite files given "toregister" result
    for path in argv:
        # reconstruct redbaron - trade CPU for memory
        red = redbaron.RedBaron(readpath(path))
        changed = False
        for node, method, args, section, name in uiconfigitems(red):
            key = (section, name)
            defaultrepr = toregister.get(key)
            if defaultrepr is None or key not in coreconfigs:
                continue
            if len(args) >= 3 and (args[2].target is None or
                                   args[2].target.value == 'default'):
                try:
                    del args[2]
                    changed = True
                except Exception:
                    # redbaron fails to do the rewrite due to indentation
                    # see https://github.com/PyCQA/redbaron/issues/100
                    print('[warn] %s: %s.%s: default needs manual removal'
                          % (path, section, name))
            if key not in registered:
                print('registering %s.%s' % (section, name))
                registercoreconfig(cfgred, section, name, defaultrepr)
                registered.add(key)
        if changed:
            print('updating %s' % path)
            writepath(path, red.dumps())

    if toregister:
        print('updating configitems.py')
        writepath(cfgpath, cfgred.dumps())

if __name__ == "__main__":
    sys.exit(main(sys.argv[1:]))

--- a/mercurial/filemerge.py	Tue Jul 11 08:52:55 2017 -0700
+++ b/mercurial/filemerge.py	Fri Jul 14 14:22:40 2017 -0700
@@ -685,7 +685,7 @@
 
     r = 1
     try:
-        markerstyle = ui.config('ui', 'mergemarkers', 'basic')
+        markerstyle = ui.config('ui', 'mergemarkers')
         if not labels:
             labels = _defaultconflictlabels
         if markerstyle != 'basic':