Amazingly, timegm(gmtime(0)) is only 0 before 2020 because perl's
timegm deviates from GNU timegm(3) in how it handles years.

man Time::Local says

 Whenever possible, use an absolute four digit year instead.

with a detailed explanation about ambiguity of 2-digit years above that.

Even though this ambiguity is error-prone with >50% of users getting it
wrong, it has been like this for 20+ years, so we just use 4-digit years
everywhere to be on the safe side.

We add some extra logic to cvsimport because it allows 2-digit year
input and interpreting an 18 as 1918 can be avoided easily and safely.

Signed-off-by: Bernhard M. Wiedemann <bwiedemann@suse.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Signed-off-by: Junio C Hamano <gitster@pobox.com>

Doc update.

* ab/doc-cat-file-e-still-shows-errors:
  cat-file doc: document that -e will return some output

Doc update.

* as/read-tree-prefix-doc-fix:
  doc/read-tree: remove obsolete remark

"git add -p" was taught to ignore local changes to submodules as
they do not interfere with the partial addition of regular changes
anyway.

* nd/add-i-ignore-submodules:
  add--interactive: ignore submodule changes except HEAD

"git stash -- <pathspec>" incorrectly blew away untracked files in
the directory that matched the pathspec, which has been corrected.

* tg/stash-with-pathspec-fix:
  stash: don't delete untracked files that match pathspec

"git clone $there $here" is allowed even when here directory exists
as long as it is an empty directory, but the command incorrectly
removed it upon a failure of the operation.

* jk/abort-clone-with-existing-dest:
  clone: do not clean up directories we didn't create
  clone: factor out dir_exists() helper
  t5600: modernize style
  t5600: fix outdated comment about unborn HEAD

"git merge -Xours/-Xtheirs" learned to use our/their version when
resolving a conflicting updates to a symbolic link.

* jc/merge-symlink-ours-theirs:
  merge: teach -Xours/-Xtheirs to symbolic link merge

API clean-up around revision traversal.

* rs/lose-leak-pending:
  commit: remove unused function clear_commit_marks_for_object_array()
  revision: remove the unused flag leak_pending
  checkout: avoid using the rev_info flag leak_pending
  bundle: avoid using the rev_info flag leak_pending
  bisect: avoid using the rev_info flag leak_pending
  object: add clear_commit_marks_all()
  ref-filter: use clear_commit_marks_many() in do_merge_filter()
  commit: use clear_commit_marks_many() in remove_redundant()
  commit: avoid allocation in clear_commit_marks_many()

"git svn dcommit" did not take into account the fact that a
svn+ssh:// URL with a username@ (typically used for pushing) refers
to the same SVN repository without the username@ and failed when
svn.pushmergeinfo option is set.

* jm/svn-pushmergeinfo-fix:
  git-svn: fix svn.pushmergeinfo handling of svn+ssh usernames.