relnotes/5.6

tests: treat `select` as a built-in module on Windows

This fixes:

    --- C:/Users/Matt/hg/tests/test-check-module-imports.t
    +++ C:/Users/Matt/hg/tests/test-check-module-imports.t.err
    @@ -43,3 +43,15 @@
       > -X tests/test-verify-repo-operations.py \
       > -X tests/test-extension.t \
       > | sed 's-\\-/-g' | "$PYTHON" "$import_checker" -
    +  hgext/zeroconf/Zeroconf.py:86: stdlib import "socket" follows local import: select\r (esc)
    +  hgext/zeroconf/Zeroconf.py:87: stdlib import "struct" follows local import: select\r (esc)
    +  hgext/zeroconf/Zeroconf.py:88: stdlib import "threading" follows local import: select\r (esc)
    +  hgext/zeroconf/Zeroconf.py:89: stdlib import "time" follows local import: select\r (esc)
    +  hgext/zeroconf/Zeroconf.py:90: stdlib import "traceback" follows local import: select\r (esc)
    +  mercurial/posix.py:18: stdlib import "stat" follows local import: select\r (esc)
    +  mercurial/posix.py:19: stdlib import "sys" follows local import: select\r (esc)
    +  mercurial/posix.py:20: stdlib import "tempfile" follows local import: select\r (esc)
    +  mercurial/posix.py:21: stdlib import "typing" follows local import: select\r (esc)
    +  tests/tinyproxy.py:19: stdlib import "socket" follows local import: select\r (esc)
    +  tests/tinyproxy.py:20: stdlib import "sys" follows local import: select\r (esc)
    +  [1]

    ERROR: test-check-module-imports.t output changed

== New Features ==

 * `hg mv -A` can now be used with `--at-rev`. It behaves just like
   `hg cp -A --at-rev`, i.e. it marks the destination as a copy of the
   source whether or not the source still exists (but the source must
   exist in the parent revision).

 * New revset predicate `diffcontains(pattern)` for filtering revisions
   in the same way as `hg grep --diff pattern`.

 * The memory footprint per changeset and per file during pull/unbundle
   operations has been significantly reduced.


== New Experimental Features ==



== Bug Fixes ==



== Backwards Compatibility Changes ==



== Internal API Changes ==

 * `merge.update()` is now private (renamed to `_update()`). Hopefully
   the higher-level functions available in the same module cover your
   use cases.

 * `phases.registernew` now takes a set of revisions instead of a list
   of nodes. `phases.advanceboundary` takes an optional set of revisions
   in addition to the list of nodes. The corresponeding members of the
   `phasecache` class follow this change.

 * The `addgroup` member of `revlog` classes no longer keeps a list of
   all found nodes. It now returns True iff a node was found in the group.
   An optional callback for duplicated nodes can be used by callers to keep
   track of all nodes themselve.

 * The `_chaininfocache` of `revlog` classes has been changed from a dict
   to a LRU cache.