wireprotov2: change how revisions are specified to changesetdata
Right now, we have a handful of arguments for specifying the revisions
whose data should be returned. Defining how all these arguments
interact when various combinations are present is difficult.
This commit establishes a new, generic mechanism for specifying
revisions. Instead of a hodgepodge of arguments defining things, we
have a list of dicts that specify revision selectors. The final set
of revisions is a union of all these selectors.
We implement support for specifying revisions based on:
* An explicit list of changeset revisions
* An explicit list of changeset revisions plus ancestry depth
* A DAG range between changeset roots and heads
If you squint hard enough, this problem has already been solved by
revsets. But I'm reluctant to expose revsets to the wire protocol
because that would require servers to implement a revset parser.
Plus there are security and performance implications: the set
of revision selectors needs to be narrowly and specifically tailored
for what is appropriate to be executing on a server. Perhaps there
would be a way for us to express the "parse tree" of a revset
query, for example. I'm not sure. We can explore this space another
time. For now, the new mechanism should bring sufficient flexibility
while remaining relatively simple.
The selector "types" are prefixed with "changeset" because I plan
to add manifest and file-flavored selectors as well. This will enable
us to e.g. select file revisions based on a range of changeset
revisions.
Differential Revision: https://phab.mercurial-scm.org/D4979
# Helper script used for generating history and working copy files and content.
# The file's name corresponds to its history. The number of changesets can
# be specified on the command line. With 2 changesets, files with names like
# content1_content2_content1-untracked are generated. The first two filename
# segments describe the contents in the two changesets. The third segment
# ("content1-untracked") describes the state in the working copy, i.e.
# the file has content "content1" and is untracked (since it was previously
# tracked, it has been forgotten).
#
# This script generates the filenames and their content, but it's up to the
# caller to tell hg about the state.
#
# There are two subcommands:
# filelist <numchangesets>
# state <numchangesets> (<changeset>|wc)
#
# Typical usage:
#
# $ python $TESTDIR/generate-working-copy-states.py state 2 1
# $ hg addremove --similarity 0
# $ hg commit -m 'first'
#
# $ python $TESTDIR/generate-working-copy-states.py state 2 1
# $ hg addremove --similarity 0
# $ hg commit -m 'second'
#
# $ python $TESTDIR/generate-working-copy-states.py state 2 wc
# $ hg addremove --similarity 0
# $ hg forget *_*_*-untracked
# $ rm *_*_missing-*
from __future__ import absolute_import, print_function
import os
import sys
# Generates pairs of (filename, contents), where 'contents' is a list
# describing the file's content at each revision (or in the working copy).
# At each revision, it is either None or the file's actual content. When not
# None, it may be either new content or the same content as an earlier
# revisions, so all of (modified,clean,added,removed) can be tested.
def generatestates(maxchangesets, parentcontents):
depth = len(parentcontents)
if depth == maxchangesets + 1:
for tracked in (b'untracked', b'tracked'):
filename = b"_".join([(content is None and b'missing' or content)
for content in parentcontents]) + b"-" + tracked
yield (filename, parentcontents)
else:
for content in ({None, b'content' + (b"%d" % (depth + 1))} |
set(parentcontents)):
for combination in generatestates(maxchangesets,
parentcontents + [content]):
yield combination
# retrieve the command line arguments
target = sys.argv[1]
maxchangesets = int(sys.argv[2])
if target == 'state':
depth = sys.argv[3]
# sort to make sure we have stable output
combinations = sorted(generatestates(maxchangesets, []))
# compute file content
content = []
for filename, states in combinations:
if target == 'filelist':
print(filename.decode('ascii'))
elif target == 'state':
if depth == 'wc':
# Make sure there is content so the file gets written and can be
# tracked. It will be deleted outside of this script.
content.append((filename, states[maxchangesets] or b'TOBEDELETED'))
else:
content.append((filename, states[int(depth) - 1]))
else:
print("unknown target:", target, file=sys.stderr)
sys.exit(1)
# write actual content
for filename, data in content:
if data is not None:
f = open(filename, 'wb')
f.write(data + b'\n')
f.close()
elif os.path.exists(filename):
os.remove(filename)