drawdag: update test repos by drawing the changelog DAG in ASCII
Currently, we have "debugbuilddag" which is a powerful tool to build test
cases but not intuitive. We may end up running "hg log" in the test to make
the test more readable.
This patch adds a "drawdag" extension with a "debugdrawdag" command for
similar testing purpose. Unlike the cryptic "debugbuilddag" command, it
reads an ASCII graph that is intuitive to human, so the test case can be
more readable.
Unlike "debugbuilddag", "drawdag" does not require an empty repo. So it can
be used to add new changesets to an existing repo.
Since the "drawdag" logic is not that trivial and only makes sense for
testing purpose, the extension is added to the "tests" directory, to make
the core logic clean. If we find it useful (for example, to demonstrate
cases and help user understand some cases) and want to ship it by default in
the future, we can move it to a ship-by-default "debugdrawdag" at that time.
# drawdag.py - convert ASCII revision DAG to actual changesets
#
# Copyright 2016 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.
"""
create changesets from an ASCII graph for testing purpose.
For example, given the following input::
c d
|/
b
|
a
4 changesets and 4 local tags will be created.
`hg log -G -T "{rev} {desc} (tag: {tags})"` will output::
o 3 d (tag: d tip)
|
| o 2 c (tag: c)
|/
o 1 b (tag: b)
|
o 0 a (tag: a)
For root nodes (nodes without parents) in the graph, they can be revsets
pointing to existing nodes. The ASCII graph could also have disconnected
components with same names referring to the same changeset.
Therefore, given the repo having the 4 changesets (and tags) above, with the
following ASCII graph as input::
foo bar bar foo
| / | |
ancestor(c,d) a baz
The result (`hg log -G -T "{desc}"`) will look like::
o foo
|\
+---o bar
| | |
| o | baz
| /
+---o d
| |
+---o c
| |
o | b
|/
o a
Note that if you take the above `hg log` output directly as input. It will work
as expected - the result would be an isomorphic graph::
o foo
|\
| | o d
| |/
| | o c
| |/
| | o bar
| |/|
| o | b
| |/
o / baz
/
o a
This is because 'o' is specially handled in the input: instead of using 'o' as
the node name, the word to the right will be used.
"""
from __future__ import absolute_import, print_function
import collections
import itertools
from mercurial.i18n import _
from mercurial import (
cmdutil,
context,
error,
node,
scmutil,
)
cmdtable = {}
command = cmdutil.command(cmdtable)
_pipechars = '\\/+-|'
_nonpipechars = ''.join(chr(i) for i in xrange(33, 127)
if chr(i) not in _pipechars)
def _isname(ch):
"""char -> bool. return True if ch looks like part of a name, False
otherwise"""
return ch in _nonpipechars
def _parseasciigraph(text):
"""str -> {str : [str]}. convert the ASCII graph to edges"""
lines = text.splitlines()
edges = collections.defaultdict(list) # {node: []}
def get(y, x):
"""(int, int) -> char. give a coordinate, return the char. return a
space for anything out of range"""
if x < 0 or y < 0:
return ' '
try:
return lines[y][x]
except IndexError:
return ' '
def getname(y, x):
"""(int, int) -> str. like get(y, x) but concatenate left and right
parts. if name is an 'o', try to replace it to the right"""
result = ''
for i in itertools.count(0):
ch = get(y, x - i)
if not _isname(ch):
break
result = ch + result
for i in itertools.count(1):
ch = get(y, x + i)
if not _isname(ch):
break
result += ch
if result == 'o':
# special handling, find the name to the right
result = ''
for i in itertools.count(2):
ch = get(y, x + i)
if ch == ' ' or ch in _pipechars:
if result or x + i >= len(lines[y]):
break
else:
result += ch
return result or 'o'
return result
def parents(y, x):
"""(int, int) -> [str]. follow the ASCII edges at given position,
return a list of parents"""
visited = set([(y, x)])
visit = []
result = []
def follow(y, x, expected):
"""conditionally append (y, x) to visit array, if it's a char
in excepted. 'o' in expected means an '_isname' test.
if '-' (or '+') is not in excepted, and get(y, x) is '-' (or '+'),
the next line (y + 1, x) will be checked instead."""
ch = get(y, x)
if any(ch == c and c not in expected for c in '-+'):
y += 1
return follow(y + 1, x, expected)
if ch in expected or ('o' in expected and _isname(ch)):
visit.append((y, x))
# -o- # starting point:
# /|\ # follow '-' (horizontally), and '/|\' (to the bottom)
follow(y + 1, x, '|')
follow(y + 1, x - 1, '/')
follow(y + 1, x + 1, '\\')
follow(y, x - 1, '-')
follow(y, x + 1, '-')
while visit:
y, x = visit.pop()
if (y, x) in visited:
continue
visited.add((y, x))
ch = get(y, x)
if _isname(ch):
result.append(getname(y, x))
continue
elif ch == '|':
follow(y + 1, x, '/|o')
follow(y + 1, x - 1, '/')
follow(y + 1, x + 1, '\\')
elif ch == '+':
follow(y, x - 1, '-')
follow(y, x + 1, '-')
follow(y + 1, x - 1, '/')
follow(y + 1, x + 1, '\\')
follow(y + 1, x, '|')
elif ch == '\\':
follow(y + 1, x + 1, '\\|o')
elif ch == '/':
follow(y + 1, x - 1, '/|o')
elif ch == '-':
follow(y, x - 1, '-+o')
follow(y, x + 1, '-+o')
return result
for y, line in enumerate(lines):
for x, ch in enumerate(line):
if ch == '#': # comment
break
if _isname(ch):
edges[getname(y, x)] += parents(y, x)
return dict(edges)
class simplefilectx(object):
def __init__(self, path, data):
self._data = data
self._path = path
def data(self):
return self._data
def path(self):
return self._path
def renamed(self):
return None
def flags(self):
return ''
class simplecommitctx(context.committablectx):
def __init__(self, repo, name, parentctxs, added=None):
opts = {
'changes': scmutil.status([], added or [], [], [], [], [], []),
'date': '0 0',
'extra': {'branch': 'default'},
}
super(simplecommitctx, self).__init__(self, name, **opts)
self._repo = repo
self._name = name
self._parents = parentctxs
self._parents.sort(key=lambda c: c.node())
while len(self._parents) < 2:
self._parents.append(repo[node.nullid])
def filectx(self, key):
return simplefilectx(key, self._name)
def commit(self):
return self._repo.commitctx(self)
def _walkgraph(edges):
"""yield node, parents in topologically order"""
visible = set(edges.keys())
remaining = {} # {str: [str]}
for k, vs in edges.iteritems():
for v in vs:
if v not in remaining:
remaining[v] = []
remaining[k] = vs[:]
while remaining:
leafs = [k for k, v in remaining.items() if not v]
if not leafs:
raise error.Abort(_('the graph has cycles'))
for leaf in sorted(leafs):
if leaf in visible:
yield leaf, edges[leaf]
del remaining[leaf]
for k, v in remaining.iteritems():
if leaf in v:
v.remove(leaf)
@command('debugdrawdag', [])
def debugdrawdag(ui, repo, **opts):
"""read an ASCII graph from stdin and create changesets
The ASCII graph is like what :hg:`log -G` outputs, with each `o` replaced
to the name of the node. The command will create dummy changesets and local
tags with those names to make the dummy changesets easier to be referred
to.
If the name of a node is a single character 'o', It will be replaced by the
word to the right. This makes it easier to reuse
:hg:`log -G -T '{desc}'` outputs.
For root (no parents) nodes, revset can be used to query existing repo.
Note that the revset cannot have confusing characters which can be seen as
the part of the graph edges, like `|/+-\`.
"""
text = ui.fin.read()
# parse the graph and make sure len(parents) <= 2 for each node
edges = _parseasciigraph(text)
for k, v in edges.iteritems():
if len(v) > 2:
raise error.Abort(_('%s: too many parents: %s')
% (k, ' '.join(v)))
committed = {None: node.nullid} # {name: node}
# for leaf nodes, try to find existing nodes in repo
for name, parents in edges.iteritems():
if len(parents) == 0:
try:
committed[name] = scmutil.revsingle(repo, name)
except error.RepoLookupError:
pass
# commit in topological order
for name, parents in _walkgraph(edges):
if name in committed:
continue
pctxs = [repo[committed[n]] for n in parents]
ctx = simplecommitctx(repo, name, pctxs, [name])
n = ctx.commit()
committed[name] = n
repo.tag(name, n, message=None, user=None, date=None, local=True)