view tests/test-narrow-clone-non-narrow-server.t @ 38486:4c0683655599

namespaces: let namespaces override singlenode() definition

Some namespaces have multiple nodes per name (meaning that their
namemap() returns multiple nodes). One such namespace is the "topics"
namespace (from the evolve repo). We also have our own internal
namespace at Google (for review units) that has multiple nodes per
name. These namespaces may not want to use the default "pick highest
revnum" resolution that we currently use when resolving a name to a
single node. As an example, they may decide that `hg co <name>` should
check out a commit that's last in some sense even if an earlier commit
had just been amended and thus had a higher revnum [1]. This patch
gives the namespace the option to continue to return multiple nodes
and to override how the best node is picked. Allowing namespaces to
override that may also be useful as an optimization (it may be cheaper
for the namespace to find just that node).

I have been arguing (in D3715) for using all the nodes returned from
namemap() when resolving the symbol to a revset, so e.g. `hg log -r
stable` would resolve to *all* nodes on stable, not just the one with
the highest revnum (except that I don't actually think we should
change it for the branch namespace because of BC). Most people seem
opposed to that. If we decide not to do it, I think we can deprecate
the namemap() function in favor of the new singlenode() (I find it
weird to have namespaces, like the branch namespace, where namemap()
isn't nodemap()'s inverse). I therefore think this patch makes sense
regardless of what we decide on that issue.


 [1] Actually, even the branch namespace would have wanted to override
     singlenode() if it had supported multiple nodes. That's because
     closes branch heads are mostly ignored, so "hg co default" will
     not check out the highest-revnum node if that's a closed head.

Differential Revision: https://phab.mercurial-scm.org/D3852

Test attempting a narrow clone against a server that doesn't support narrowhg.

  $ . "$TESTDIR/narrow-library.sh"

  $ hg init master
  $ cd master

  $ for x in `$TESTDIR/seq.py 10`; do
  >   echo $x > "f$x"
  >   hg add "f$x"
  >   hg commit -m "Add $x"
  > done

  $ hg serve -a localhost -p $HGPORT1 --config extensions.narrow=! -d \
  >    --pid-file=hg.pid
  $ cat hg.pid >> "$DAEMON_PIDS"
  $ hg serve -a localhost -p $HGPORT2 -d --pid-file=hg.pid
  $ cat hg.pid >> "$DAEMON_PIDS"

Verify that narrow is advertised in the bundle2 capabilities:

  $ cat >> unquote.py <<EOF
  > from __future__ import print_function
  > import sys
  > if sys.version[0] == '3':
  >     import urllib.parse as up
  >     unquote = up.unquote_plus
  > else:
  >     import urllib
  >     unquote = urllib.unquote_plus
  > print(unquote(list(sys.stdin)[1]))
  > EOF
  $ echo hello | hg -R . serve --stdio | \
  >   $PYTHON unquote.py | grep narrow
  narrow=v0

  $ cd ..

  $ hg clone --narrow --include f1 http://localhost:$HGPORT1/ narrowclone
  requesting all changes
  abort: server doesn't support narrow clones
  [255]

Make a narrow clone (via HGPORT2), then try to narrow and widen
into it (from HGPORT1) to prove that narrowing is fine and widening fails
gracefully:
  $ hg clone -r 0 --narrow --include f1 http://localhost:$HGPORT2/ narrowclone
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  new changesets * (glob)
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd narrowclone
  $ hg tracked --addexclude f2 http://localhost:$HGPORT1/
  comparing with http://localhost:$HGPORT1/
  searching for changes
  looking for local changes to affected paths
  $ hg tracked --addinclude f1 http://localhost:$HGPORT1/
  comparing with http://localhost:$HGPORT1/
  searching for changes
  no changes found
  abort: server doesn't support narrow clones
  [255]