tests/test-simple-update.t

templatekw: choose {latesttag} by len(changes), not date (issue5659)

As Augie reported in the bug, the current heuristic of choosing the
best tag of a merge commit by taking the one with newest tag (in terms
of tagging date) currently fails in the Mercurial repo itself. Copying
the example from Yuya:

  $ hg glog -T '{node|short} {latesttag}+{latesttagdistance}\n' \
    -r '4.2.3: & (merge() + parents(merge()) + tag())'
  o    02a745c20121 4.2.3+5
  |\
  | o    86aca74a063b 4.2.3+4
  | |\
  | | o  e6d8ee3c9ec3 4.3-rc+109
  | | |
  | | ~
  o |  a3ce07e2dde5 4.3.1+2
  : |
  o |  3fee7f7d2da0 4.3.1+0
  |/
  o    98e990bb7330 4.2.3+3
  |\
  | ~
  o  506d7e48fbe6 4.2.3+2
  :
  o  943c91326b23 4.2.3+0
  |
  ~

It seems to me like the best choice is the tag with the smallest
number of changes since it (across all paths, not the longest single
path). So that's what this patch does, even though it's
costly. Best-of-5 timings for Yuya's command above shows a slowdown
from 1.293s to 1.610s. We can optimize it later.

Differential Revision: https://phab.mercurial-scm.org/D447

  $ hg init test
  $ cd test
  $ echo foo>foo
  $ hg addremove
  adding foo
  $ hg commit -m "1"

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 1 changesets, 1 total revisions

  $ hg clone . ../branch
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd ../branch
  $ hg co
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo bar>>foo
  $ hg commit -m "2"

  $ cd ../test

  $ hg pull ../branch
  pulling from ../branch
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  (run 'hg update' to get a working copy)

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 2 changesets, 2 total revisions

  $ hg co
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ cat foo
  foo
  bar

  $ hg manifest --debug
  6f4310b00b9a147241b071a60c28a650827fb03d 644   foo

update to rev 0 with a date

  $ hg upd -d foo 0
  abort: you can't specify a revision and a date
  [255]

  $ cd ..

update with worker processes

#if no-windows

  $ cat <<EOF > forceworker.py
  > from mercurial import extensions, worker
  > def nocost(orig, ui, costperop, nops):
  >     return worker._numworkers(ui) > 1
  > def uisetup(ui):
  >     extensions.wrapfunction(worker, 'worthwhile', nocost)
  > EOF

  $ hg init worker
  $ cd worker
  $ cat <<EOF >> .hg/hgrc
  > [extensions]
  > forceworker = $TESTTMP/forceworker.py
  > [worker]
  > numcpus = 4
  > EOF
  $ for i in `$PYTHON $TESTDIR/seq.py 1 100`; do
  >   echo $i > $i
  > done
  $ hg ci -qAm 'add 100 files'

  $ hg update null
  0 files updated, 0 files merged, 100 files removed, 0 files unresolved
  $ hg update -v | grep 100
  getting 100
  100 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ cd ..

#endif