Doc updates.

* ah/doc-updates:
  doc: fix formatting in git-update-ref
  doc: fix indentation of listing blocks in gitweb.conf.txt
  doc: fix descripion for 'git tag --format'
  doc: fix inappropriate monospace formatting
  doc: fix ASCII art tab spacing
  doc: clarify boundaries of 'git worktree list --porcelain'

Trivial bugfix.

* ds/reachable:
  commit-reach: fix cast in compare_commits_by_gen()

The receive.denyCurrentBranch=updateInstead codepath kicked in even
when the push should have been rejected due to other reasons, such
as it does not fast-forward or the update-hook rejects it, which
has been corrected.

* jc/receive-deny-current-branch-fix:
  receive: denyCurrentBranch=updateinstead should not blindly update

One of our CI tests to run with "unusual/experimental/random"
settings now also uses commit-graph and midx.

* ds/ci-commit-graph-and-midx:
  ci: add optional test variables

Developer support.

* jk/unused-function:
  config.mak.dev: enable -Wunused-function

Code clean-up.

* cb/remove-dead-init:
  multi-pack-index: avoid dead store for struct progress
  unpack-trees: avoid dead store for struct progress

Under certain circumstances, "git diff D:/a/b/c D:/a/b/d" on
Windows would strip initial parts from the paths because they
were not recognized as absolute, which has been corrected.

* js/diff-notice-has-drive-prefix:
  diff: don't attempt to strip prefix from absolute Windows paths

Plugging a handful of memory leaks in the ref-filter codepath.

* ot/ref-filter-plug-leaks:
  ref-filter: free item->value and item->value->s
  ls-remote: release memory instead of UNLEAK
  ref-filter: free memory from used_atom

Correct performance regression in commit ancestry computation when
generation numbers are involved.

* ds/reachable-first-parent-fix:
  commit-reach: fix first-parent heuristic

Code clean-up.

* rj/header-guards:
  headers: normalize the spelling of some header guards

Developer support.

* jk/test-tool-help:
  test-tool: show tool list on error

Docfix.

* sg/doc-show-branch-typofix:
  doc: fix small typo in git show-branch

Code clean-up.

* sb/submodule-helper-remove-cruft:
  builtin/submodule--helper: remove debugging leftover tracing

A mutex used in "git pack-objects" were not correctly initialized
and this caused "git repack" to dump core on Windows.

* js/pack-objects-mutex-init-fix:
  pack-objects (mingw): initialize `packing_data` mutex in the correct spot
  pack-objects (mingw): demonstrate a segmentation fault with large deltas
  pack-objects: fix typo 'detla' -> 'delta'

Code clean-up.

* tq/branch-style-fix:
  branch: trivial style fix

Code clean-up.

* tq/branch-create-wo-branch-get:
  builtin/branch.c: remove useless branch_get

More codepaths are moving away from hardcoded hash sizes.

* bc/hash-transition-part-15:
  rerere: convert to use the_hash_algo
  submodule: make zero-oid comparison hash function agnostic
  apply: rename new_sha1_prefix and old_sha1_prefix
  apply: replace hard-coded constants
  tag: express constant in terms of the_hash_algo
  transport: use parse_oid_hex instead of a constant
  upload-pack: express constants in terms of the_hash_algo
  refs/packed-backend: express constants using the_hash_algo
  packfile: express constants in terms of the_hash_algo
  pack-revindex: express constants in terms of the_hash_algo
  builtin/fetch-pack: remove constants with parse_oid_hex
  builtin/mktree: remove hard-coded constant
  builtin/repack: replace hard-coded constants
  pack-bitmap-write: use GIT_MAX_RAWSZ for allocation
  object_id.cocci: match only expressions of type 'struct object_id'

Code clean-up to serve as a BCP example.

* sb/strbuf-h-update:
  strbuf.h: format according to coding guidelines

The implementation of run_command() API on the UNIX platforms had a
bug that caused a command not on $PATH to be found in the current
directory.

* jk/run-command-notdot:
  run-command: mark path lookup errors with ENOENT

Test fix.

* tb/filter-alternate-refs:
  t5410: use longer path for sample script
  Documentation/config.txt: fix typo in core.alternateRefsCommand

"git send-email" learned to grab address-looking string on any
trailer whose name ends with "-by"; --suppress-cc=misc-by on the
command line, or setting sendemail.suppresscc configuration
variable to "misc-by", can be used to disable this behaviour.

This is a backward-incompatible change that may surprise existing
users.

* rv/send-email-cc-misc-by:
  send-email: also pick up cc addresses from -by trailers
  send-email: only consider lines containing @ or <> for automatic Cc'ing
  Documentation/git-send-email.txt: style fixes

"git range-diff" did not work well when the compared ranges had
changes in submodules and the "--submodule=log" was used.

* lm/range-diff-submodule-fix:
  range-diff: allow to diff files regardless of submodule config

Build update for "git subtree" (in contrib/) documentation pages.

* ch/subtree-build:
  Revert "subtree: make install targets depend on build targets"
  subtree: make install targets depend on build targets
  subtree: add build targets 'man' and 'html'

The "rev-list --filter" feature learned to exclude all trees via
"tree:0" filter.

* md/filter-trees:
  list-objects: support for skipping tree traversal
  filter-trees: code clean-up of tests
  list-objects-filter: implement filter tree:0
  list-objects-filter-options: do not over-strbuf_init
  list-objects-filter: use BUG rather than die
  revision: mark non-user-given objects instead
  rev-list: handle missing tree objects properly
  list-objects: always parse trees gently
  list-objects: refactor to process_tree_contents
  list-objects: store common func args in struct

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

The logic to select the default user name and e-mail on Windows has
been improved.

* js/mingw-default-ident:
  mingw: use domain information for default email
  getpwuid(mingw): provide a better default for the user name
  getpwuid(mingw): initialize the structure only once

"git p4 unshelve" improvements.

* ld/p4-unshelve:
  git-p4: fully support unshelving changelists
  git-p4: unshelve into refs/remotes/p4-unshelved, not refs/remotes/p4/unshelved
  git-p4: do not fail in verbose mode for missing 'fileSize' key

Doc update to mark "git cherry" as a plumbing command.

* du/cherry-is-plumbing:
  doc: move git-cherry to plumbing

The documentation of "git gc" has been updated to mention that it
is no longer limited to "pruning away crufts" but also updates
ancillary files like commit-graph as a part of repository
optimization.

* ab/gc-doc-update:
  gc doc: mention the commit-graph in the intro

An experiment to fuzz test a few areas, hopefully we can gain more
coverage to various areas.

* js/fuzzer:
  fuzz: add fuzz testing for packfile indices.
  fuzz: add basic fuzz testing target.

"git cmd --help" when "cmd" is aliased used to only say "cmd is
aliased to ...".  Now it shows that to the standard error stream
and runs "git $cmd --help" where $cmd is the first word of the
alias expansion.

This could be misleading for those who alias a command with options
(e.g. with "[alias] cpn = cherry-pick -n", "git cpn --help" would
show the manual of "cherry-pick", and the reader would not be told
to pay close attention to the part that describes the "--no-commit"
option until closing the pager that showed the contents of the
manual, if the pager is configured to restore the original screen,
or would not be told at all, if the pager simply makes the message
on the standard error scroll away.

* rv/alias-help:
  git-help.txt: document "git help cmd" vs "git cmd --help" for aliases
  git.c: handle_alias: prepend alias info when first argument is -h
  help: redirect to aliased commands for "git cmd --help"

Code clean-up.

* sb/diff-emit-line-ws-markup-cleanup:
  diff.c: pass sign_index to emit_line_ws_markup

Doc update to mark "git get-tar-commit-id" as a plumbing command.

* du/get-tar-commit-id-is-plumbing:
  doc: move git-get-tar-commit-id to plumbing

Doc update.

* mm/doc-no-dashed-git:
  doc: fix a typo and clarify a sentence

Doc update.

* du/rev-parse-is-plumbing:
  doc: move git-rev-parse from porcelain to plumbing

"git log --graph" showing an octopus merge sometimes miscounted the
number of display columns it is consuming to show the merge and its
parent commits, which has been corrected.

* np/log-graph-octopus-fix:
  log: fix coloring of certain octopus merge shapes

The codepath to support the experimental split-index mode had
remaining "racily clean" issues fixed.

* sg/split-index-racefix:
  split-index: BUG() when cache entry refers to non-existing shared entry
  split-index: smudge and add racily clean cache entries to split index
  split-index: don't compare cached data of entries already marked for split index
  split-index: count the number of deleted entries
  t1700-split-index: date back files to avoid racy situations
  split-index: add tests to demonstrate the racy split index problem
  t1700-split-index: document why FSMONITOR is disabled in this test script

The result of coverage test can be combined with "git blame" to
check the test coverage of code introduced recently with a new
'coverage-diff' tool (in contrib/).

* ds/coverage-diff:
  contrib: add coverage-diff script

To help developers, an EditorConfig file that attempts to follow
the project convention has been added.

* bc/editorconfig:
  editorconfig: indicate settings should be kept in sync
  editorconfig: provide editor settings for Git developers

Test fix.

* ma/t7005-bash-workaround:
  t7005-editor: quote filename to fix whitespace-issue