help: document bundle specifications
I softly formalized the concept of a "bundle specification" a while
ago when I was working on clone bundles and stream clone bundles and
wanted a more robust way to define what exactly is in a bundle file.
The concept has existed for a while. Since it is part of the clone
bundles feature and exposed to the user via the "-t" argument to
`hg bundle`, it is something we need to support for the long haul.
After the 4.1 release, I heard a few people comment that they didn't
realize you could generate zstd bundles with `hg bundle`. I'm
partially to blame for not documenting it in bundle's docstring.
Additionally, I added a hacky, experimental feature for controlling
the compression level of bundles in 76104a4899ad. As the commit
message says, I went with a quick and dirty solution out of time
constraints. Furthermore, I wanted to eventually store this
configuration in the "bundlespec" so it could be made more flexible.
Given:
a) bundlespecs are here to stay
b) we don't have great documentation over what they are, despite being
a user-facing feature
c) the list of available compression engines and their behavior isn't
exposed
d) we need an extensible place to modify behavior of compression
engines
I want to move forward with formalizing bundlespecs as a user-facing
feature. This commit does that by introducing a "bundlespec" help
page. Leaning on the just-added compression engine documentation
and API, the topic also conveniently lists available compression
engines and details about them. This makes features like zstd
bundle compression more discoverable. e.g. you can now
`hg help -k zstd` and it lists the "bundlespec" topic.
from __future__ import absolute_import, print_function
import collections
import struct
import unittest
from mercurial import (
bdiff,
mpatch,
)
class diffreplace(
collections.namedtuple('diffreplace', 'start end from_ to')):
def __repr__(self):
return 'diffreplace(%r, %r, %r, %r)' % self
class BdiffTests(unittest.TestCase):
def assert_bdiff_applies(self, a, b):
d = bdiff.bdiff(a, b)
c = a
if d:
c = mpatch.patches(a, [d])
self.assertEqual(
c, b, ("bad diff+patch result from\n %r to\n "
"%r: \nbdiff: %r\npatched: %r" % (a, b, d, c[:200])))
def assert_bdiff(self, a, b):
self.assert_bdiff_applies(a, b)
self.assert_bdiff_applies(b, a)
def test_bdiff_basic(self):
cases = [
("a\nc\n\n\n\n", "a\nb\n\n\n"),
("a\nb\nc\n", "a\nc\n"),
("", ""),
("a\nb\nc", "a\nb\nc"),
("a\nb\nc\nd\n", "a\nd\n"),
("a\nb\nc\nd\n", "a\nc\ne\n"),
("a\nb\nc\n", "a\nc\n"),
("a\n", "c\na\nb\n"),
("a\n", ""),
("a\n", "b\nc\n"),
("a\n", "c\na\n"),
("", "adjfkjdjksdhfksj"),
("", "ab"),
("", "abc"),
("a", "a"),
("ab", "ab"),
("abc", "abc"),
("a\n", "a\n"),
("a\nb", "a\nb"),
]
for a, b in cases:
self.assert_bdiff(a, b)
def showdiff(self, a, b):
bin = bdiff.bdiff(a, b)
pos = 0
q = 0
actions = []
while pos < len(bin):
p1, p2, l = struct.unpack(">lll", bin[pos:pos + 12])
pos += 12
if p1:
actions.append(a[q:p1])
actions.append(diffreplace(p1, p2, a[p1:p2], bin[pos:pos + l]))
pos += l
q = p2
if q < len(a):
actions.append(a[q:])
return actions
def test_issue1295(self):
cases = [
("x\n\nx\n\nx\n\nx\n\nz\n", "x\n\nx\n\ny\n\nx\n\nx\n\nz\n",
['x\n\nx\n\n', diffreplace(6, 6, '', 'y\n\n'), 'x\n\nx\n\nz\n']),
("x\n\nx\n\nx\n\nx\n\nz\n", "x\n\nx\n\ny\n\nx\n\ny\n\nx\n\nz\n",
['x\n\nx\n\n',
diffreplace(6, 6, '', 'y\n\n'),
'x\n\n',
diffreplace(9, 9, '', 'y\n\n'),
'x\n\nz\n']),
]
for old, new, want in cases:
self.assertEqual(self.showdiff(old, new), want)
def test_issue1295_varies_on_pure(self):
# we should pick up abbbc. rather than bc.de as the longest match
got = self.showdiff("a\nb\nb\nb\nc\n.\nd\ne\n.\nf\n",
"a\nb\nb\na\nb\nb\nb\nc\n.\nb\nc\n.\nd\ne\nf\n")
want_c = ['a\nb\nb\n',
diffreplace(6, 6, '', 'a\nb\nb\nb\nc\n.\n'),
'b\nc\n.\nd\ne\n',
diffreplace(16, 18, '.\n', ''),
'f\n']
want_pure = [diffreplace(0, 0, '', 'a\nb\nb\n'),
'a\nb\nb\nb\nc\n.\n',
diffreplace(12, 12, '', 'b\nc\n.\n'),
'd\ne\n',
diffreplace(16, 18, '.\n', ''), 'f\n']
self.assert_(got in (want_c, want_pure),
'got: %r, wanted either %r or %r' % (
got, want_c, want_pure))
def test_fixws(self):
cases = [
(" \ta\r b\t\n", "ab\n", 1),
(" \ta\r b\t\n", " a b\n", 0),
("", "", 1),
("", "", 0),
]
for a, b, allws in cases:
c = bdiff.fixws(a, allws)
self.assertEqual(
c, b, 'fixws(%r) want %r got %r (allws=%r)' % (a, b, c, allws))
def test_nice_diff_for_trivial_change(self):
self.assertEqual(self.showdiff(
''.join('<%s\n-\n' % i for i in range(5)),
''.join('>%s\n-\n' % i for i in range(5))),
[diffreplace(0, 3, '<0\n', '>0\n'),
'-\n',
diffreplace(5, 8, '<1\n', '>1\n'),
'-\n',
diffreplace(10, 13, '<2\n', '>2\n'),
'-\n',
diffreplace(15, 18, '<3\n', '>3\n'),
'-\n',
diffreplace(20, 23, '<4\n', '>4\n'),
'-\n'])
def test_prefer_appending(self):
# 1 line to 3 lines
self.assertEqual(self.showdiff('a\n', 'a\n' * 3),
['a\n', diffreplace(2, 2, '', 'a\na\n')])
# 1 line to 5 lines
self.assertEqual(self.showdiff('a\n', 'a\n' * 5),
['a\n', diffreplace(2, 2, '', 'a\na\na\na\n')])
def test_prefer_removing_trailing(self):
# 3 lines to 1 line
self.assertEqual(self.showdiff('a\n' * 3, 'a\n'),
['a\n', diffreplace(2, 6, 'a\na\n', '')])
# 5 lines to 1 line
self.assertEqual(self.showdiff('a\n' * 5, 'a\n'),
['a\n', diffreplace(2, 10, 'a\na\na\na\n', '')])
if __name__ == '__main__':
import silenttestrunner
silenttestrunner.main(__name__)