Merge branch 'jc/push-cert' into jch

Allow "git push" request to be signed, so that it can be verified
audited, using the GPG signature of the person who pushed, that the
tips of branches at a public repository really point the commits
the pusher wanted to, without having to "trust" the server.

* jc/push-cert: (23 commits)
  signed push: allow stale nonce in stateless mode
  signed push: teach smart-HTTP to pass "git push --signed" around
  signed push: fortify against replay attacks
  signed push: add "pushee" header to push certificate
  signed push: remove duplicated protocol info
  send-pack: send feature request on push-cert packet
  receive-pack: GPG-validate push certificates
  push: the beginning of "git push --signed"
  pack-protocol doc: typofix for PKT-LINE
  gpg-interface: move parse_signature() to where it should be
  gpg-interface: move parse_gpg_output() to where it should be
  send-pack: clarify that cmds_sent is a boolean
  send-pack: refactor inspecting and resetting status and sending commands
  send-pack: rename "new_refs" to "need_pack_data"
  receive-pack: factor out capability string generation
  send-pack: factor out capability string generation
  send-pack: always send capabilities
  send-pack: refactor decision to send update per ref
  send-pack: move REF_STATUS_REJECT_NODELETE logic a bit higher
  receive-pack: factor out queueing of command
  ...
Merge branch 'pr/use-default-sigpipe-setting' into jch

We used to get confused when a process called us with SIGPIPE
ignored; we do want to die with SIGPIPE when the output is not
read by default, and do ignore the signal when appropriate.

* pr/use-default-sigpipe-setting:
  mingw.h: add dummy functions for sigset_t operations
  unblock and unignore SIGPIPE
Merge branch 'sb/merge-recursive-copy-paste-fix' into jch

"git merge-recursive" had a small bug that could have made it
mishandle "one side deleted, the other side did not touch it" in a
rare corner case, where the other side actually did touch to cause
the blob object names to be different but both blobs before and
after the change normalize to the same (e.g. correcting mistake to
check in a blob with CRLF line endings by replacing it with another
blob that records the same contents with LF line endings).

* sb/merge-recursive-copy-paste-fix:
  merge-recursive: remove stale commented debugging code
  merge-recursive: fix copy-paste mistake
### match next
Merge branch 'sp/stream-clean-filter' into jch

* sp/stream-clean-filter:
  sha1_file: don't convert off_t to size_t too early to avoid potential die()
  convert: stream from fd to required clean filter to reduce used address space
  copy_fd(): do not close the input file descriptor
  mmap_limit: introduce GIT_MMAP_LIMIT to allow testing expected mmap size
  memory_limit: use git_env_ulong() to parse GIT_ALLOC_LIMIT
  config.c: add git_env_ulong() to parse environment variable
  convert: drop arguments other than 'path' from would_convert_to_git()

# Conflicts:
# 	wrapper.c
Merge branch 'nd/archive-pathspec' into jch

"git archive" learned to filter what gets archived with pathspec.

* nd/archive-pathspec:
  archive: support filtering paths with glob
Merge branch 'tr/remerge-diff' into jch

"log -p" output learns a new way to let users inspect a merge
commit by showing the differences between the automerged result
with conflicts the person who recorded the merge would have seen
and the final conflict resolution that was recorded in the merge.

Review comments sent.

* tr/remerge-diff:
  log --remerge-diff: show what the conflict resolution changed
  name-hash: allow dir hashing even when !ignore_case
  merge-recursive: allow storing conflict hunks in index
  merge_diff_mode: fold all merge diff variants into an enum
  combine-diff: do not pass revs->dense_combined_merges redundantly
  merge-recursive: -Xindex-only to leave worktree unchanged
  merge-recursive: internal flag to avoid touching the worktree
  merge-recursive: remove dead conditional in update_stages()

# Conflicts:
# 	merge-recursive.c
Merge branch 'da/include-compat-util-first-in-c' into jch

* da/include-compat-util-first-in-c:
  SQUASH???
  check-headers: add header usage checks for .c files
  Makefile: add check-headers target
  cleanups: ensure that git-compat-util.h is included first
Merge branch 'so/rebase-doc-fork-point' into jch

* so/rebase-doc-fork-point:
  Documentation/git-rebase.txt: document when --fork-point is auto-enabled
Merge branch 'sk/tag-contains-wo-recursion' into jch

* sk/tag-contains-wo-recursion:
  t7004: give the test a bit more stack space
Merge branch 'jt/itimer-autoconf' into jch

* jt/itimer-autoconf:
  autoconf: check for setitimer()
  autoconf: check for struct itimerval
  git-compat-util.h: add missing semicolon after struct itimerval
Merge branch 'cc/interpret-trailers' into pu

A new filter to programatically edit the tail end of the commit log
messages.

Discussion on the topic with Michael Tsirkin who wants to utilize
this machinery is going on.  Finally a real functionality review
that is very much welcomed ;-).

* cc/interpret-trailers:
  Documentation: add documentation for 'git interpret-trailers'
  trailer: add tests for commands in config file
  trailer: execute command from 'trailer.<name>.command'
  trailer: add tests for "git interpret-trailers"
  trailer: add interpret-trailers command
  trailer: put all the processing together and print
  trailer: parse trailers from file or stdin
  trailer: process command line trailer arguments
  trailer: read and process config information
  trailer: process trailers from input message and arguments
  trailer: add data structures and basic functions
Merge branch 'mh/lockfile' into pu

Rerolled, reviews in progress; it seems that we will see another reroll?

* mh/lockfile: (35 commits)
  get_locked_file_path(): new function
  lockfile.c: rename static functions
  lockfile: rename LOCK_NODEREF to LOCK_NO_DEREF
  commit_locked_index(): extract a function commit_lock_file_to()
  trim_last_path_component(): replace last_path_elm()
  resolve_symlink(): take a strbuf parameter
  resolve_symlink(): use a strbuf for internal scratch space
  struct lock_file: change the filename member into a strbuf
  commit_lock_file(): use a strbuf to manage temporary space
  try_merge_strategy(): use a statically-allocated lock_file object
  try_merge_strategy(): remove redundant lock_file allocation
  struct lock_file: declare some fields volatile
  lockfile: avoid transitory invalid states
  git_config_set_multivar_in_file(): avoid call to rollback_lock_file()
  dump_marks(): remove a redundant call to rollback_lock_file()
  api-lockfile: document edge cases
  commit_lock_file(): rollback lock file on failure to rename
  commit_lock_file(): if close fails, roll back
  commit_lock_file(): die() if called for unlocked lockfile object
  commit_lock_file(): inline temporary variable
  ...

# Conflicts:
# 	lockfile.c
# 	refs.c
Merge branch 'nd/multiple-work-trees' into pu

A replacement for contrib/workdir/git-new-workdir that does not
rely on symbolic links and make sharing of objects and refs safer
by making the borrowee and borrowers aware of each other.

Rerolled, reviews in progress; it seems that we will see another reroll?

* nd/multiple-work-trees: (32 commits)
  t2025: add a test to make sure grafts is working from a linked checkout
  checkout: don't require a work tree when checking out into a new one
  git_path(): keep "info/sparse-checkout" per work-tree
  count-objects: report unused files in $GIT_DIR/worktrees/...
  gc: support prune --worktrees
  gc: factor out gc.pruneexpire parsing code
  gc: style change -- no SP before closing parenthesis
  checkout: clean up half-prepared directories in --to mode
  checkout: reject if the branch is already checked out elsewhere
  prune: strategies for linked checkouts
  checkout: support checking out into a new working directory
  use new wrapper write_file() for simple file writing
  wrapper.c: wrapper to open a file, fprintf then close
  setup.c: support multi-checkout repo setup
  setup.c: detect $GIT_COMMON_DIR check_repository_format_gently()
  setup.c: convert check_repository_format_gently to use strbuf
  setup.c: detect $GIT_COMMON_DIR in is_git_directory()
  setup.c: convert is_git_directory() to use strbuf
  git-stash: avoid hardcoding $GIT_DIR/logs/....
  *.sh: avoid hardcoding $GIT_DIR/hooks/...
  ...

# Conflicts:
# 	builtin/gc.c
# 	builtin/receive-pack.c
# 	refs.c
# 	refs.h
# 	trace.c
# 	wrapper.c
Merge branch 'hv/submodule-config' into pu

Kicked back to 'pu' per request ($gmane/255610).

* hv/submodule-config:
  do not die on error of parsing fetchrecursesubmodules option
  use new config API for worktree configurations of submodules
  extract functions for submodule config set and lookup
  implement submodule config cache for lookup of submodule names
Merge branch 'jt/timer-settime' into pu

Reviewed, discussed and wanting for a reroll.

* jt/timer-settime:
  use timer_settime() for new platforms
  autoconf: check for timer_settime()
  autoconf: check for struct itimerspec
  autoconf: check for struct sigevent
  autoconf: check for struct timespec
  autoconf: check for timer_t
Merge branch 'jc/test-lazy-prereq' into pu

Test-script clean-up.

* jc/test-lazy-prereq:
  tests: drop GIT_*_TIMING_TESTS environment variable support
Merge branch 'mt/patch-id-stable' into pu

Teaches "git patch-id" to compute the patch ID that does not change
when the files in a single patch is reordered. As this new algorithm
is backward incompatible, the last bit to flip it to be the default
is left out of 'master' for now.

Nobody seems to be jumping up & down requesting this last step,
which makes the result somewhat backward incompatible.

* mt/patch-id-stable:
  patch-id: change default to stable
Merge branch 'cb/mergetool-difftool' into pu

Update the way the "difftool --help" shows the help message that is
shared with the "mergetool" to reduce one shell dependency.

* cb/mergetool-difftool:
  difftool: don't assume that default sh is sane
  mergetool: don't require a work tree for --tool-help
Merge branch 'po/everyday-doc' into pu

This may make the said command to emit something, but the source is
not meant to be formatted into a manual pages to begin with, and
also its contents are a bit stale.  It may be a good first step in
the right direction, but needs more work to at least get the
mark-up right before public consumption.

* po/everyday-doc:
  Make 'git help everyday' work

# Conflicts:
# 	Documentation/Makefile