tests/test-hgrc.t

streamclone: define first iteration of version 2 of stream format

(This patch is based on a first draft from Gregory Szorc, with deeper rework)

Version 1 of the stream clone format was invented many years ago and suffers
from a few deficiencies:

1) Filenames are stored in store-encoded (on filesystem) form rather than in
   their internal form. This makes future compatibility with new store
   filename encodings more difficult.
2) File entry "headers" consist of a newline of the file name followed by the
   string file size. Converting strings to integers is avoidable overhead. We
   can't store filenames with newlines (manifests have this limitation as
   well, so it isn't a major concern). But the big concern here is the
   necessity for readline(). Scanning for newlines means reading ahead and
   that means extra buffer allocations and slicing (in Python) and this makes
   performance suffer.
3) Filenames aren't compressed optimally. Filenames should be compressed well
   since there is a lot of repeated data. However, since they are scattered
   all over the stream (with revlog data in between), they typically fall
   outside the window size of the compressor and don't compress.
4) It can only exchange stored based content, being able to exchange caches
   too would be nice.
5) It is limited to a stream-based protocol and isn't suitable for an on-disk
   format for general repository reading because the offset of individual file
   entries requires scanning the entire file to find file records.

As part of enabling streaming clones to work in bundle2, #2 proved to have a
significant negative impact on performance. Since bundle2 provides the
opportunity to start fresh, Gregory Szorc figured he would take the
opportunity to invent a new streaming clone data format.

The new format devised in this series addresses #1, #2, and #4. It punts on #3
because it was complex without yielding a significant gain and on #5 because
devising a new store format that "packs" multiple revlogs into a single
"packed revlog" is massive scope bloat. However, this v2 format might be
suitable for streaming into a "packed revlog" with minimal processing. If it
works, great. If not, we can always invent stream format when it is needed.

This patch only introduces the bases of the format. We'll get it usable through
bundle2 first, then we'll extend the format in future patches to bring it to its
full potential (especially #4).

hide outer repo
  $ hg init

Use hgrc within $TESTTMP

  $ HGRCPATH=`pwd`/hgrc
  $ export HGRCPATH

Use an alternate var for scribbling on hgrc to keep check-code from
complaining about the important settings we may be overwriting:

  $ HGRC=`pwd`/hgrc
  $ export HGRC

Basic syntax error

  $ echo "invalid" > $HGRC
  $ hg version
  hg: parse error at $TESTTMP/hgrc:1: invalid
  [255]
  $ echo "" > $HGRC

Issue1199: Can't use '%' in hgrc (eg url encoded username)

  $ hg init "foo%bar"
  $ hg clone "foo%bar" foobar
  updating to branch default
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd foobar
  $ cat .hg/hgrc
  # example repository config (see 'hg help config' for more info)
  [paths]
  default = $TESTTMP/foo%bar
  
  # path aliases to other clones of this repo in URLs or filesystem paths
  # (see 'hg help config.paths' for more info)
  #
  # default:pushurl = ssh://[e-mail]/hg/jdoes-fork
  # my-fork         = ssh://[e-mail]/hg/jdoes-fork
  # my-clone        = /home/jdoe/jdoes-clone
  
  [ui]
  # name and email (local to this repository, optional), e.g.
  # username = Jane Doe <[e-mail]>
  $ hg paths
  default = $TESTTMP/foo%bar
  $ hg showconfig
  bundle.mainreporoot=$TESTTMP/foobar
  paths.default=$TESTTMP/foo%bar
  $ cd ..

issue1829: wrong indentation

  $ echo '[foo]' > $HGRC
  $ echo '  x = y' >> $HGRC
  $ hg version
  hg: parse error at $TESTTMP/hgrc:2:   x = y
  unexpected leading whitespace
  [255]

  $ $PYTHON -c "print '[foo]\nbar = a\n b\n c \n  de\n fg \nbaz = bif cb \n'" \
  > > $HGRC
  $ hg showconfig foo
  foo.bar=a\nb\nc\nde\nfg
  foo.baz=bif cb

  $ FAKEPATH=/path/to/nowhere
  $ export FAKEPATH
  $ echo '%include $FAKEPATH/no-such-file' > $HGRC
  $ hg version
  Mercurial Distributed SCM (version *) (glob)
  (see https://mercurial-scm.org for more information)
  
  Copyright (C) 2005-* Matt Mackall and others (glob)
  This is free software; see the source for copying conditions. There is NO
  warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  $ unset FAKEPATH

make sure global options given on the cmdline take precedence

  $ hg showconfig --config ui.verbose=True --quiet
  bundle.mainreporoot=$TESTTMP
  ui.verbose=False
  ui.debug=False
  ui.quiet=True

  $ touch foobar/untracked
  $ cat >> foobar/.hg/hgrc <<EOF
  > [ui]
  > verbose=True
  > EOF
  $ hg -R foobar st -q

username expansion

  $ olduser=$HGUSER
  $ unset HGUSER

  $ FAKEUSER='John Doe'
  $ export FAKEUSER
  $ echo '[ui]' > $HGRC
  $ echo 'username = $FAKEUSER' >> $HGRC

  $ hg init usertest
  $ cd usertest
  $ touch bar
  $ hg commit --addremove --quiet -m "added bar"
  $ hg log --template "{author}\n"
  John Doe
  $ cd ..

  $ hg showconfig
  bundle.mainreporoot=$TESTTMP
  ui.username=$FAKEUSER

  $ unset FAKEUSER
  $ HGUSER=$olduser
  $ export HGUSER

showconfig with multiple arguments

  $ echo "[alias]" > $HGRC
  $ echo "log = log -g" >> $HGRC
  $ echo "[defaults]" >> $HGRC
  $ echo "identify = -n" >> $HGRC
  $ hg showconfig alias defaults
  alias.log=log -g
  defaults.identify=-n
  $ hg showconfig alias defaults.identify
  abort: only one config item permitted
  [255]
  $ hg showconfig alias.log defaults.identify
  abort: only one config item permitted
  [255]

HGPLAIN

  $ echo "[ui]" > $HGRC
  $ echo "debug=true" >> $HGRC
  $ echo "fallbackencoding=ASCII" >> $HGRC
  $ echo "quiet=true" >> $HGRC
  $ echo "slash=true" >> $HGRC
  $ echo "traceback=true" >> $HGRC
  $ echo "verbose=true" >> $HGRC
  $ echo "style=~/.hgstyle" >> $HGRC
  $ echo "logtemplate={node}" >> $HGRC
  $ echo "[defaults]" >> $HGRC
  $ echo "identify=-n" >> $HGRC
  $ echo "[alias]" >> $HGRC
  $ echo "log=log -g" >> $HGRC

customized hgrc

  $ hg showconfig
  read config from: $TESTTMP/hgrc
  $TESTTMP/hgrc:13: alias.log=log -g
  repo: bundle.mainreporoot=$TESTTMP
  $TESTTMP/hgrc:11: defaults.identify=-n
  $TESTTMP/hgrc:2: ui.debug=true
  $TESTTMP/hgrc:3: ui.fallbackencoding=ASCII
  $TESTTMP/hgrc:4: ui.quiet=true
  $TESTTMP/hgrc:5: ui.slash=true
  $TESTTMP/hgrc:6: ui.traceback=true
  $TESTTMP/hgrc:7: ui.verbose=true
  $TESTTMP/hgrc:8: ui.style=~/.hgstyle
  $TESTTMP/hgrc:9: ui.logtemplate={node}

plain hgrc

  $ HGPLAIN=; export HGPLAIN
  $ hg showconfig --config ui.traceback=True --debug
  read config from: $TESTTMP/hgrc
  repo: bundle.mainreporoot=$TESTTMP
  --config: ui.traceback=True
  --verbose: ui.verbose=False
  --debug: ui.debug=True
  --quiet: ui.quiet=False

with environment variables

  $ PAGER=p1 EDITOR=e1 VISUAL=e2 hg showconfig --debug
  set config by: $EDITOR
  set config by: $VISUAL
  set config by: $PAGER
  read config from: $TESTTMP/hgrc
  repo: bundle.mainreporoot=$TESTTMP
  $PAGER: pager.pager=p1
  $VISUAL: ui.editor=e2
  --verbose: ui.verbose=False
  --debug: ui.debug=True
  --quiet: ui.quiet=False

plain mode with exceptions

  $ cat > plain.py <<EOF
  > from mercurial import commands, extensions
  > def _config(orig, ui, repo, *values, **opts):
  >     ui.write('plain: %r\n' % ui.plain())
  >     return orig(ui, repo, *values, **opts)
  > def uisetup(ui):
  >     extensions.wrapcommand(commands.table, 'config', _config)
  > EOF
  $ echo "[extensions]" >> $HGRC
  $ echo "plain=./plain.py" >> $HGRC
  $ HGPLAINEXCEPT=; export HGPLAINEXCEPT
  $ hg showconfig --config ui.traceback=True --debug
  plain: True
  read config from: $TESTTMP/hgrc
  repo: bundle.mainreporoot=$TESTTMP
  $TESTTMP/hgrc:15: extensions.plain=./plain.py
  --config: ui.traceback=True
  --verbose: ui.verbose=False
  --debug: ui.debug=True
  --quiet: ui.quiet=False
  $ unset HGPLAIN
  $ hg showconfig --config ui.traceback=True --debug
  plain: True
  read config from: $TESTTMP/hgrc
  repo: bundle.mainreporoot=$TESTTMP
  $TESTTMP/hgrc:15: extensions.plain=./plain.py
  --config: ui.traceback=True
  --verbose: ui.verbose=False
  --debug: ui.debug=True
  --quiet: ui.quiet=False
  $ HGPLAINEXCEPT=i18n; export HGPLAINEXCEPT
  $ hg showconfig --config ui.traceback=True --debug
  plain: True
  read config from: $TESTTMP/hgrc
  repo: bundle.mainreporoot=$TESTTMP
  $TESTTMP/hgrc:15: extensions.plain=./plain.py
  --config: ui.traceback=True
  --verbose: ui.verbose=False
  --debug: ui.debug=True
  --quiet: ui.quiet=False

source of paths is not mangled

  $ cat >> $HGRCPATH <<EOF
  > [paths]
  > foo = bar
  > EOF
  $ hg showconfig --debug paths
  plain: True
  read config from: $TESTTMP/hgrc
  $TESTTMP/hgrc:17: paths.foo=$TESTTMP/bar