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httppeer: remove support for connecting to <0.9.1 servers (BC)...
httppeer: remove support for connecting to <0.9.1 servers (BC) Previously, HTTP wire protocol clients would attempt a "capabilities" wire protocol command. If that failed, they would fall back to issuing a "between" command. The "capabilities" command was added in Mercurial 0.9.1 (released July 2006). The "between" command has been present for as long as the wire protocol has existed. So if the "between" command failed, it was safe to assume that the remote could not speak any version of the Mercurial wire protocol. The "between" fallback was added in 395a84f78736 in 2011. Before that changeset, Mercurial would *always* issue the "between" command and would issue "capabilities" if capabilities were requested. At that time, many connections would issue "capabilities" eventually, so it was decided to issue "capabilities" by default and fall back to "between" if that failed. This saved a round trip when connecting to modern servers while still preserving compatibility with legacy servers. Fast forward ~7 years. Mercurial servers supporting "capabilities" have been around for over a decade. If modern clients are connecting to <0.9.1 servers, they are getting a bad experience. They may even be getting bad data (an old server is vulnerable to numerous security issues and could have been p0wned, leading to a Mercurial repository serving backdoors or other badness). In addition, the fallback can harm experience for modern servers. If a client experiences an intermittent HTTP request failure (due to bad network, etc) and falls back to a "between" that works, it would assume an empty capability set and would attempt to communicate with the repository using a very ancient wire protocol. Auditing HTTP logs for hg.mozilla.org, I did find a handful of requests for the null range of the "between" command. However, requests can be days apart. And when I do see requests, they come in batches. Those batches seem to correlate to spikes of HTTP 500 or other server/network events. So I think these requests are fallbacks from failed "capabilities" requests and not from old clients. If you need even more evidence to discontinue support, apparently we have no test coverage for communicating with servers not supporting "capabilities." I know this because all tests pass with the "between" fallback removed. Finally, server-side support for <0.9.1 pushing (the "addchangegroup" wire protocol command along with locking-related commands) was dropped from the HTTP client in fda0867cfe03 in 2017 and the SSH client in 9f6e0e7ef828 in 2015. I think this all adds up to enough justification for removing client support for communicating with servers not supporting "capabilities." So this commit removes that fallback. Differential Revision: https://phab.mercurial-scm.org/D2001

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graphmod.py
478 lines | 16.4 KiB | text/x-python | PythonLexer
# Revision graph generator for Mercurial
#
# Copyright 2008 Dirkjan Ochtman <dirkjan@ochtman.nl>
# Copyright 2007 Joel Rosdahl <joel@rosdahl.net>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""supports walking the history as DAGs suitable for graphical output
The most basic format we use is that of::
(id, type, data, [parentids])
The node and parent ids are arbitrary integers which identify a node in the
context of the graph returned. Type is a constant specifying the node type.
Data depends on type.
"""
from __future__ import absolute_import
from .node import nullrev
from . import (
dagop,
smartset,
util,
)
CHANGESET = 'C'
PARENT = 'P'
GRANDPARENT = 'G'
MISSINGPARENT = 'M'
# Style of line to draw. None signals a line that ends and is removed at this
# point. A number prefix means only the last N characters of the current block
# will use that style, the rest will use the PARENT style. Add a - sign
# (so making N negative) and all but the first N characters use that style.
EDGES = {PARENT: '|', GRANDPARENT: ':', MISSINGPARENT: None}
def dagwalker(repo, revs):
"""cset DAG generator yielding (id, CHANGESET, ctx, [parentinfo]) tuples
This generator function walks through revisions (which should be ordered
from bigger to lower). It returns a tuple for each node.
Each parentinfo entry is a tuple with (edgetype, parentid), where edgetype
is one of PARENT, GRANDPARENT or MISSINGPARENT. The node and parent ids
are arbitrary integers which identify a node in the context of the graph
returned.
"""
gpcache = {}
for rev in revs:
ctx = repo[rev]
# partition into parents in the rev set and missing parents, then
# augment the lists with markers, to inform graph drawing code about
# what kind of edge to draw between nodes.
pset = set(p.rev() for p in ctx.parents() if p.rev() in revs)
mpars = [p.rev() for p in ctx.parents()
if p.rev() != nullrev and p.rev() not in pset]
parents = [(PARENT, p) for p in sorted(pset)]
for mpar in mpars:
gp = gpcache.get(mpar)
if gp is None:
# precompute slow query as we know reachableroots() goes
# through all revs (issue4782)
if not isinstance(revs, smartset.baseset):
revs = smartset.baseset(revs)
gp = gpcache[mpar] = sorted(set(dagop.reachableroots(
repo, revs, [mpar])))
if not gp:
parents.append((MISSINGPARENT, mpar))
pset.add(mpar)
else:
parents.extend((GRANDPARENT, g) for g in gp if g not in pset)
pset.update(gp)
yield (ctx.rev(), CHANGESET, ctx, parents)
def nodes(repo, nodes):
"""cset DAG generator yielding (id, CHANGESET, ctx, [parentids]) tuples
This generator function walks the given nodes. It only returns parents
that are in nodes, too.
"""
include = set(nodes)
for node in nodes:
ctx = repo[node]
parents = set((PARENT, p.rev()) for p in ctx.parents()
if p.node() in include)
yield (ctx.rev(), CHANGESET, ctx, sorted(parents))
def colored(dag, repo):
"""annotates a DAG with colored edge information
For each DAG node this function emits tuples::
(id, type, data, (col, color), [(col, nextcol, color)])
with the following new elements:
- Tuple (col, color) with column and color index for the current node
- A list of tuples indicating the edges between the current node and its
parents.
"""
seen = []
colors = {}
newcolor = 1
config = {}
for key, val in repo.ui.configitems('graph'):
if '.' in key:
branch, setting = key.rsplit('.', 1)
# Validation
if setting == "width" and val.isdigit():
config.setdefault(branch, {})[setting] = int(val)
elif setting == "color" and val.isalnum():
config.setdefault(branch, {})[setting] = val
if config:
getconf = util.lrucachefunc(
lambda rev: config.get(repo[rev].branch(), {}))
else:
getconf = lambda rev: {}
for (cur, type, data, parents) in dag:
# Compute seen and next
if cur not in seen:
seen.append(cur) # new head
colors[cur] = newcolor
newcolor += 1
col = seen.index(cur)
color = colors.pop(cur)
next = seen[:]
# Add parents to next
addparents = [p for pt, p in parents if p not in next]
next[col:col + 1] = addparents
# Set colors for the parents
for i, p in enumerate(addparents):
if not i:
colors[p] = color
else:
colors[p] = newcolor
newcolor += 1
# Add edges to the graph
edges = []
for ecol, eid in enumerate(seen):
if eid in next:
bconf = getconf(eid)
edges.append((
ecol, next.index(eid), colors[eid],
bconf.get('width', -1),
bconf.get('color', '')))
elif eid == cur:
for ptype, p in parents:
bconf = getconf(p)
edges.append((
ecol, next.index(p), color,
bconf.get('width', -1),
bconf.get('color', '')))
# Yield and move on
yield (cur, type, data, (col, color), edges)
seen = next
def asciiedges(type, char, state, rev, parents):
"""adds edge info to changelog DAG walk suitable for ascii()"""
seen = state['seen']
if rev not in seen:
seen.append(rev)
nodeidx = seen.index(rev)
knownparents = []
newparents = []
for ptype, parent in parents:
if parent == rev:
# self reference (should only be seen in null rev)
continue
if parent in seen:
knownparents.append(parent)
else:
newparents.append(parent)
state['edges'][parent] = state['styles'].get(ptype, '|')
ncols = len(seen)
width = 1 + ncols * 2
nextseen = seen[:]
nextseen[nodeidx:nodeidx + 1] = newparents
edges = [(nodeidx, nextseen.index(p)) for p in knownparents]
seen[:] = nextseen
while len(newparents) > 2:
# ascii() only knows how to add or remove a single column between two
# calls. Nodes with more than two parents break this constraint so we
# introduce intermediate expansion lines to grow the active node list
# slowly.
edges.append((nodeidx, nodeidx))
edges.append((nodeidx, nodeidx + 1))
nmorecols = 1
width += 2
yield (type, char, width, (nodeidx, edges, ncols, nmorecols))
char = '\\'
nodeidx += 1
ncols += 1
edges = []
del newparents[0]
if len(newparents) > 0:
edges.append((nodeidx, nodeidx))
if len(newparents) > 1:
edges.append((nodeidx, nodeidx + 1))
nmorecols = len(nextseen) - ncols
if nmorecols > 0:
width += 2
# remove current node from edge characters, no longer needed
state['edges'].pop(rev, None)
yield (type, char, width, (nodeidx, edges, ncols, nmorecols))
def _fixlongrightedges(edges):
for (i, (start, end)) in enumerate(edges):
if end > start:
edges[i] = (start, end + 1)
def _getnodelineedgestail(
echars, idx, pidx, ncols, coldiff, pdiff, fix_tail):
if fix_tail and coldiff == pdiff and coldiff != 0:
# Still going in the same non-vertical direction.
if coldiff == -1:
start = max(idx + 1, pidx)
tail = echars[idx * 2:(start - 1) * 2]
tail.extend(["/", " "] * (ncols - start))
return tail
else:
return ["\\", " "] * (ncols - idx - 1)
else:
remainder = (ncols - idx - 1)
return echars[-(remainder * 2):] if remainder > 0 else []
def _drawedges(echars, edges, nodeline, interline):
for (start, end) in edges:
if start == end + 1:
interline[2 * end + 1] = "/"
elif start == end - 1:
interline[2 * start + 1] = "\\"
elif start == end:
interline[2 * start] = echars[2 * start]
else:
if 2 * end >= len(nodeline):
continue
nodeline[2 * end] = "+"
if start > end:
(start, end) = (end, start)
for i in range(2 * start + 1, 2 * end):
if nodeline[i] != "+":
nodeline[i] = "-"
def _getpaddingline(echars, idx, ncols, edges):
# all edges up to the current node
line = echars[:idx * 2]
# an edge for the current node, if there is one
if (idx, idx - 1) in edges or (idx, idx) in edges:
# (idx, idx - 1) (idx, idx)
# | | | | | | | |
# +---o | | o---+
# | | X | | X | |
# | |/ / | |/ /
# | | | | | |
line.extend(echars[idx * 2:(idx + 1) * 2])
else:
line.extend([' ', ' '])
# all edges to the right of the current node
remainder = ncols - idx - 1
if remainder > 0:
line.extend(echars[-(remainder * 2):])
return line
def _drawendinglines(lines, extra, edgemap, seen):
"""Draw ending lines for missing parent edges
None indicates an edge that ends at between this node and the next
Replace with a short line ending in ~ and add / lines to any edges to
the right.
"""
if None not in edgemap.values():
return
# Check for more edges to the right of our ending edges.
# We need enough space to draw adjustment lines for these.
edgechars = extra[::2]
while edgechars and edgechars[-1] is None:
edgechars.pop()
shift_size = max((edgechars.count(None) * 2) - 1, 0)
while len(lines) < 3 + shift_size:
lines.append(extra[:])
if shift_size:
empties = []
toshift = []
first_empty = extra.index(None)
for i, c in enumerate(extra[first_empty::2], first_empty // 2):
if c is None:
empties.append(i * 2)
else:
toshift.append(i * 2)
targets = list(range(first_empty, first_empty + len(toshift) * 2, 2))
positions = toshift[:]
for line in lines[-shift_size:]:
line[first_empty:] = [' '] * (len(line) - first_empty)
for i in range(len(positions)):
pos = positions[i] - 1
positions[i] = max(pos, targets[i])
line[pos] = '/' if pos > targets[i] else extra[toshift[i]]
map = {1: '|', 2: '~'}
for i, line in enumerate(lines):
if None not in line:
continue
line[:] = [c or map.get(i, ' ') for c in line]
# remove edges that ended
remove = [p for p, c in edgemap.items() if c is None]
for parent in remove:
del edgemap[parent]
seen.remove(parent)
def asciistate():
"""returns the initial value for the "state" argument to ascii()"""
return {
'seen': [],
'edges': {},
'lastcoldiff': 0,
'lastindex': 0,
'styles': EDGES.copy(),
'graphshorten': False,
}
def ascii(ui, state, type, char, text, coldata):
"""prints an ASCII graph of the DAG
takes the following arguments (one call per node in the graph):
- ui to write to
- Somewhere to keep the needed state in (init to asciistate())
- Column of the current node in the set of ongoing edges.
- Type indicator of node data, usually 'C' for changesets.
- Payload: (char, lines):
- Character to use as node's symbol.
- List of lines to display as the node's text.
- Edges; a list of (col, next_col) indicating the edges between
the current node and its parents.
- Number of columns (ongoing edges) in the current revision.
- The difference between the number of columns (ongoing edges)
in the next revision and the number of columns (ongoing edges)
in the current revision. That is: -1 means one column removed;
0 means no columns added or removed; 1 means one column added.
"""
idx, edges, ncols, coldiff = coldata
assert -2 < coldiff < 2
edgemap, seen = state['edges'], state['seen']
# Be tolerant of history issues; make sure we have at least ncols + coldiff
# elements to work with. See test-glog.t for broken history test cases.
echars = [c for p in seen for c in (edgemap.get(p, '|'), ' ')]
echars.extend(('|', ' ') * max(ncols + coldiff - len(seen), 0))
if coldiff == -1:
# Transform
#
# | | | | | |
# o | | into o---+
# |X / |/ /
# | | | |
_fixlongrightedges(edges)
# add_padding_line says whether to rewrite
#
# | | | | | | | |
# | o---+ into | o---+
# | / / | | | # <--- padding line
# o | | | / /
# o | |
add_padding_line = (len(text) > 2 and coldiff == -1 and
[x for (x, y) in edges if x + 1 < y])
# fix_nodeline_tail says whether to rewrite
#
# | | o | | | | o | |
# | | |/ / | | |/ /
# | o | | into | o / / # <--- fixed nodeline tail
# | |/ / | |/ /
# o | | o | |
fix_nodeline_tail = len(text) <= 2 and not add_padding_line
# nodeline is the line containing the node character (typically o)
nodeline = echars[:idx * 2]
nodeline.extend([char, " "])
nodeline.extend(
_getnodelineedgestail(
echars, idx, state['lastindex'], ncols, coldiff,
state['lastcoldiff'], fix_nodeline_tail))
# shift_interline is the line containing the non-vertical
# edges between this entry and the next
shift_interline = echars[:idx * 2]
for i in xrange(2 + coldiff):
shift_interline.append(' ')
count = ncols - idx - 1
if coldiff == -1:
for i in xrange(count):
shift_interline.extend(['/', ' '])
elif coldiff == 0:
shift_interline.extend(echars[(idx + 1) * 2:ncols * 2])
else:
for i in xrange(count):
shift_interline.extend(['\\', ' '])
# draw edges from the current node to its parents
_drawedges(echars, edges, nodeline, shift_interline)
# lines is the list of all graph lines to print
lines = [nodeline]
if add_padding_line:
lines.append(_getpaddingline(echars, idx, ncols, edges))
# If 'graphshorten' config, only draw shift_interline
# when there is any non vertical flow in graph.
if state['graphshorten']:
if any(c in '\/' for c in shift_interline if c):
lines.append(shift_interline)
# Else, no 'graphshorten' config so draw shift_interline.
else:
lines.append(shift_interline)
# make sure that there are as many graph lines as there are
# log strings
extra_interline = echars[:(ncols + coldiff) * 2]
if len(lines) < len(text):
while len(lines) < len(text):
lines.append(extra_interline[:])
_drawendinglines(lines, extra_interline, edgemap, seen)
while len(text) < len(lines):
text.append("")
if any(len(char) > 1 for char in edgemap.values()):
# limit drawing an edge to the first or last N lines of the current
# section the rest of the edge is drawn like a parent line.
parent = state['styles'][PARENT][-1]
def _drawgp(char, i):
# should a grandparent character be drawn for this line?
if len(char) < 2:
return True
num = int(char[:-1])
# either skip first num lines or take last num lines, based on sign
return -num <= i if num < 0 else (len(lines) - i) <= num
for i, line in enumerate(lines):
line[:] = [c[-1] if _drawgp(c, i) else parent for c in line]
edgemap.update(
(e, (c if len(c) < 2 else parent)) for e, c in edgemap.items())
# print lines
indentation_level = max(ncols, ncols + coldiff)
for (line, logstr) in zip(lines, text):
ln = "%-*s %s" % (2 * indentation_level, "".join(line), logstr)
ui.write(ln.rstrip() + '\n')
# ... and start over
state['lastcoldiff'] = coldiff
state['lastindex'] = idx