Code cleanup.

* sg/t5318-cleanup:
  t5318-commit-graph: remove unused variable

Test update.

* jt/t5551-protocol-v2-does-not-have-half-auth:
  t5551: mark half-auth no-op fetch test as v0-only

dumb-http walker has been updated to share more error recovery
strategy with the normal codepath.

* jk/http-walker-status-fix:
  http: use normalize_curl_result() instead of manual conversion
  http: normalize curl results for dumb loose and alternates fetches
  http: factor out curl result code normalization

"git multi-pack-index verify" did not scale well with the number of
packfiles, which is being improved.

* jh/midx-verify-too-many-packs:
  midx: during verify group objects by packfile to speed verification
  midx: add progress indicators in multi-pack-index verify
  trace2:data: add trace2 data to midx
  progress: add sparse mode to force 100% complete message

Unicode update.

* bb/unicode-12:
  unicode: update the width tables to Unicode 12

A corner case bug in the refs API has been corrected.

* jk/refs-double-abort:
  refs/files-backend: don't look at an aborted transaction
  refs/files-backend: handle packed transaction prepare failure

Doc about the above.

* nd/checkout-m-doc-update:
  checkout.txt: note about losing staged changes with --merge

Fix some code that passed a NULL when a va_list was expected.

* tb/trace2-va-list-fix:
  trace2: NULL is not allowed for va_list

The completion helper code now pays attention to repository-local
configuration (when available), which allows --list-cmds to honour
a repository specific setting of completion.commands, for example.

* tz/completion:
  completion: use __git when calling --list-cmds
  completion: fix multiple command removals
  t9902: test multiple removals via completion.commands
  git: read local config in --list-cmds

Dev support update to make it easier to compare two formatted
results from our documentation.

* ma/doc-diff-doc-vs-doctor-comparison:
  doc-diff: add `--cut-header-footer`
  doc-diff: support diffing from/to AsciiDoc(tor)
  doc-diff: let `render_tree()` take an explicit directory name
  Doc: auto-detect changed build flags

Work-around extra warning from bash in our tests.

* tz/t4038-bash-redirect-target-workaround:
  t4038-diff-combined: quote paths with whitespace

Retire scripted "git rebase" implementation.

* ab/drop-scripted-rebase:
  rebase: remove the rebase.useBuiltin setting

Code cleanup in the test framework.

* jk/perf-lib-tee:
  perf-lib.sh: rely on test-lib.sh for --tee handling

Typofixes.

* ab/doc-misc-typofixes:
  doc: fix typos in man pages

Docfix.

* mh/pack-protocol-doc-fix:
  fix pack protocol example client/server communication

Doc update.

* tg/glossary-overlay:
  glossary: add definition for overlay

"git checkout -f <branch>" while the index has an unmerged path
incorrectly left some paths in an unmerged state, which has been
corrected.

* nd/checkout-f-while-conflicted-fix:
  unpack-trees: fix oneway_merge accidentally carry over stage index

Doc updates.

* pw/rerere-autoupdate:
  merge: tweak --rerere-autoupdate documentation
  am/cherry-pick/rebase/revert: document --rerere-autoupdate

"git format-patch" used overwrite an existing patch/cover-letter
file.  A new "--no-clobber" option stops it.

* jc/format-patch-error-check:
  format-patch: notice failure to open cover letter for writing
  builtin/log: downcase the beginning of error messages

A corner-case object name ambiguity while the sequencer machinery
is working (e.g. "rebase -i -x") has been (half) fixed.

* js/get-short-oid-drop-cache:
  get_oid(): when an object was not found, try harder
  sequencer: move stale comment into correct location
  sequencer: improve error message when an OID could not be parsed
  rebase -i: demonstrate obscure loose object cache bug

"git subtree" (in contrib/) update.

* dl/subtree-limit-to-one-rev:
  contrib/subtree: ensure only one rev is provided

"git init" forgot to read platform-specific repository
configuration, which made Windows port to ignore settings of
core.hidedotfiles, for example.

* js/init-db-update-for-mingw:
  mingw: respect core.hidedotfiles = false in git-init again

Error messages given from the http transport have been updated so
that they can be localized.

* js/remote-curl-i18n:
  remote-curl: mark all error messages for translation

remote-http transport did not anonymize URLs reported in its error
messages at places.

* js/anonymize-remote-curl-diag:
  curl: anonymize URLs in error messages and warnings

Documentation mark-up fixes.

* ma/asciidoctor-fixes-more:
  Documentation: turn middle-of-line tabs into spaces
  git-svn.txt: drop escaping '\' that ends up being rendered
  git.txt: remove empty line before list continuation
  config/fsck.txt: avoid starting line with dash
  config/diff.txt: drop spurious backtick

Build fix around use of asciidoctor instead of asciidoc

* ma/asciidoctor-fixes:
  asciidoctor-extensions: fix spurious space after linkgit
  Documentation/Makefile: add missing dependency on asciidoctor-extensions
  Documentation/Makefile: add missing xsl dependencies for manpages

Help developers by making it easier to run most of the tests under
different versions of over-the-wire protocols.

* jt/test-protocol-version:
  t5552: compensate for v2 filtering ref adv.
  tests: fix protocol version for overspecifications
  t5700: only run with protocol version 1
  t5512: compensate for v0 only sending HEAD symrefs
  t5503: fix overspecification of trace expectation
  tests: always test fetch of unreachable with v0
  t5601: check ssh command only with protocol v0
  tests: define GIT_TEST_PROTOCOL_VERSION

Third batch to teach the diff machinery to use the parse-options
API.

* nd/diff-parseopt-3:
  diff-parseopt: convert --submodule
  diff-parseopt: convert --ignore-submodules
  diff-parseopt: convert --textconv
  diff-parseopt: convert --ext-diff
  diff-parseopt: convert --quiet
  diff-parseopt: convert --exit-code
  diff-parseopt: convert --color-words
  diff-parseopt: convert --word-diff-regex
  diff-parseopt: convert --word-diff
  diff-parseopt: convert --[no-]color
  diff-parseopt: convert --[no-]follow
  diff-parseopt: convert -R
  diff-parseopt: convert -a|--text
  diff-parseopt: convert --full-index
  diff-parseopt: convert --binary
  diff-parseopt: convert --anchored
  diff-parseopt: convert --diff-algorithm
  diff-parseopt: convert --histogram
  diff-parseopt: convert --patience
  diff-parseopt: convert --[no-]indent-heuristic

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

Error message update.

* jt/submodule-fetch-errmsg:
  submodule: explain first attempt failure clearly

Build update for SHA-1 with collision detection.

* jk/sha1dc:
  Makefile: fix unaligned loads in sha1dc with UBSan

Suggest GitGitGadget instead of submitGit as a way to submit
patches based on GitHub PR to us.

* jk/promote-ggg:
  point pull requesters to GitGitGadget

Test cleanup.

* ar/t4150-remove-cruft:
  t4150: remove unused variable

"git rebase --rebase-merges" replaces its old "--preserve-merges"
option; the latter is now marked as deprecated.

* js/rebase-deprecate-preserve-merges:
  rebase: deprecate --preserve-merges

"git worktree add" used to do a "find an available name with stat
and then mkdir", which is race-prone.  This has been fixed by using
mkdir and reacting to EEXIST in a loop.

* ms/worktree-add-atomic-mkdir:
  worktree: fix worktree add race

"git log -L<from>,<to>:<path>" with "-s" did not suppress the patch
output as it should.  This has been corrected.

* jk/line-log-with-patch:
  line-log: detect unsupported formats
  line-log: suppress diff output with "-s"

A GSoC micro.

* ra/t3600-test-path-funcs:
  t3600: use helpers to replace test -d/f/e/s <path>
  t3600: modernize style
  test functions: add function `test_file_not_empty`

"git rebase" uses the refs/rewritten/ hierarchy to store its
intermediate states, which inherently makes the hierarchy per
worktree, but it didn't quite work well.

* nd/rewritten-ref-is-per-worktree:
  Make sure refs/rewritten/ is per-worktree
  files-backend.c: reduce duplication in add_per_worktree_entries_to_dir()
  files-backend.c: factor out per-worktree code in loose_fill_ref_dir()

When the "clean" filter can reduce the size of a huge file in the
working tree down to a small "token" (a la Git LFS), there is no
point in allocating a huge scratch area upfront, but the buffer is
sized based on the original file size.  The convert mechanism now
allocates very minimum and reallocates as it receives the output
from the clean filter process.

* jh/resize-convert-scratch-buffer:
  convert: avoid malloc of original file size

Doc update.

* dl/ignore-docs:
  docs: move core.excludesFile from git-add to gitignore
  git-clean.txt: clarify ignore pattern files