outgoing: add a simple fastpath when there is no common This further speed up case like `hg bundle --all` for larger repository. ### data-env-vars.name = mozilla-try-2023-03-22-zstd-sparse-revlog # benchmark.name = hg.command.bundle # bin-env-vars.hg.flavor = default # bin-env-vars.hg.py-re2-module = default # benchmark.variants.revs = all # benchmark.variants.type = none-streamv2 before: 316.749699 after: 311.165461 (-1.76%, -5.58) There is further work to be done in this area like not doing any outgoing computation in the stream case for example. however the recent changes already gives use a large win for a small amount of local work. ### benchmark.name = hg.command.bundle # bin-env-vars.hg.flavor = default # bin-env-vars.hg.py-re2-module = default # benchmark.variants.revs = all # benchmark.variants.type = none-streamv2 ## data-env-vars.name = mercurial-public-2024-03-22-zstd-sparse-revlog pre-%ln-change: 1.263859 the-%ln-change: 0.700229 (-44.60%, -0.56) prev-changeset: 0.496050 (-60.75%, -0.77) this-changeset: 0.495243 (-60.81%, -0.77) ## data-env-vars.name = tryton-public-2024-03-22-zstd-sparse-revlog pre-%ln-change: 2.975765 the-%ln-change: 1.870798 (-37.13%, -1.10) prev-changeset: 1.461583 (-50.88%, -1.51) this-changeset: 1.469185 (-50.63%, -1.51) ## data-env-vars.name = pypy-2024-03-22-zstd-sparse-revlog pre-%ln-change: 4.540080 the-%ln-change: 3.401700 (-25.07%, -1.14) prev-changeset: 2.915810 (-35.78%, -1.62) this-changeset: 2.911643 (-35.87%, -1.63) ## data-env-vars.name = heptapod-public-2024-03-25-zstd-sparse-revlog pre-%ln-change: 10.138396 the-%ln-change: 7.750458 (-23.55%, -2.39) prev-changeset: 6.665565 (-34.25%, -3.47) this-changeset: 6.672078 (-34.19%, -3.47) ## data-env-vars.name = mozilla-try-2023-03-22-zstd-sparse-revlog pre-%ln-change: 399.484481 the-%ln-change: 346.508952 (-13.26%, -52.98) prev-changeset: 316.749699 (-20.71%, -82.73) this-changeset: 311.165461 (-22.11%, -88.32)

  $ cat > echo.py <<EOF
  > #!$PYTHON
  > import os
  > import sys
  > try:
  >     import msvcrt
  >     msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
  >     msvcrt.setmode(sys.stderr.fileno(), os.O_BINARY)
  > except ImportError:
  >     pass
  > 
  > for k in ('HG_FILE', 'HG_MY_ISLINK', 'HG_OTHER_ISLINK', 'HG_BASE_ISLINK'):
  >     print(k, os.environ[k])
  > EOF

Create 2 heads containing the same file, once as
a file, once as a link. Bundle was generated with:

# hg init t
# cd t
# echo a > a
# hg ci -qAm t0 -d '0 0'
# echo l > l
# hg ci -qAm t1 -d '1 0'
# hg up -C 0
# ln -s a l
# hg ci -qAm t2 -d '2 0'
# echo l2 > l2
# hg ci -qAm t3 -d '3 0'

  $ hg init t
  $ cd t
  $ hg -q unbundle "$TESTDIR/bundles/test-merge-symlinks.hg"
  $ hg up -C 3
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved

Merge them and display *_ISLINK vars
merge heads

  $ hg merge --tool="\"$PYTHON\" ../echo.py"
  merging l
  HG_FILE l
  HG_MY_ISLINK 1
  HG_OTHER_ISLINK 0
  HG_BASE_ISLINK 0
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

Test working directory symlink bit calculation wrt copies,
especially on non-supporting systems.
merge working directory

  $ hg up -C 2
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg copy l l2
  $ HGMERGE="\"$PYTHON\" ../echo.py" hg up 3
  merging l2
  HG_FILE l2
  HG_MY_ISLINK 1
  HG_OTHER_ISLINK 0
  HG_BASE_ISLINK 0
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved

  $ cd ..