Doc formatting fix.

* tz/git-svn-doc-markup-fix:
  Documentation/git-svn: improve asciidoctor compatibility

Running "git add" on a repository created inside the current
repository is an explicit indication that the user wants to add it
as a submodule, but when the HEAD of the inner repository is on an
unborn branch, it cannot be added as a submodule.  Worse, the files
in its working tree can be added as if they are a part of the outer
repository, which is not what the user wants.  These problems are
being addressed.

* km/empty-repo-is-still-a-repo:
  add: error appropriately on repository with no commits
  dir: do not traverse repositories with no commits
  submodule: refuse to add repository with no commits

"git tag" learned to give an advice suggesting it might be a
mistake when creating an annotated or signed tag that points at
another tag.

* dl/warn-tagging-a-tag:
  tag: advise on nested tags
  tag: fix formatting

"git merge-recursive" backend recently learned a new heuristics to
infer file movement based on how other files in the same directory
moved.  As this is inherently less robust heuristics than the one
based on the content similarity of the file itself (rather than
based on what its neighbours are doing), it sometimes gives an
outcome unexpected by the end users.  This has been toned down to
leave the renamed paths in higher/conflicted stages in the index so
that the user can examine and confirm the result.

* en/merge-directory-renames:
  merge-recursive: switch directory rename detection default
  merge-recursive: give callers of handle_content_merge() access to contents
  merge-recursive: track information associated with directory renames
  t6043: fix copied test description to match its purpose
  merge-recursive: switch from (oid,mode) pairs to a diff_filespec
  merge-recursive: cleanup handle_rename_* function signatures
  merge-recursive: track branch where rename occurred in rename struct
  merge-recursive: remove ren[12]_other fields from rename_conflict_info
  merge-recursive: shrink rename_conflict_info
  merge-recursive: move some struct declarations together
  merge-recursive: use 'ci' for rename_conflict_info variable name
  merge-recursive: rename locals 'o' and 'a' to 'obuf' and 'abuf'
  merge-recursive: rename diff_filespec 'one' to 'o'
  merge-recursive: rename merge_options argument from 'o' to 'opt'
  Use 'unsigned short' for mode, like diff_filespec does

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

Build with gettext breaks on recent macOS w/ Homebrew when
/usr/local/bin is not on PATH, which has been corrected.

* js/macos-gettext-build:
  macOS: make sure that gettext is found

The recently added feature to add addresses that are on
anything-by: trailers in 'git send-email' was found to be way too
eager and considered nonsense strings as if they can be legitimate
beginning of *-by: trailer.  This has been tightened.

* bs/sendemail-tighten-anything-by:
  send-email: don't cc *-by lines with '-' prefix

"git send-email" has been taught to use quoted-printable when the
payload contains carriage-return.  The use of the mechanism is in
line with the design originally added the codepath that chooses QP
when the payload has overly long lines.

* bc/send-email-qp-cr:
  send-email: default to quoted-printable when CR is present

"git submodule foreach <command> --quiet" did not pass the option
down correctly, which has been corrected.

* nd/submodule-foreach-quiet:
  submodule foreach: fix "<command> --quiet" not being respected

Test fix on APFS that is incapable of store paths in Latin-1.

* js/iso8895-test-on-apfs:
  t9822: skip tests if file names cannot be ISO-8859-1 encoded

The GETTEXT_POISON test option has been quite broken ever since it
was made runtime-tunable, which has been fixed.

* jc/gettext-test-fix:
  gettext tests: export the restored GIT_TEST_GETTEXT_POISON

Code clean-up and a fix for "git fetch" by an explicit object name
(as opposed to fetching refs by name).

* jk/fetch-reachability-error-fix:
  fetch: do not consider peeled tags as advertised tips
  remote.c: make singular free_ref() public
  fetch: use free_refs()
  pkt-line: prepare buffer before handling ERR packets
  upload-pack: send ERR packet for non-tip objects
  t5530: check protocol response for "not our ref"
  t5516: drop ok=sigpipe from unreachable-want tests

The code is updated to check the result of memory allocation before
it is used in more places, by using xmalloc and/or xcalloc calls.

* jk/xmalloc:
  progress: use xmalloc/xcalloc
  xdiff: use xmalloc/xrealloc
  xdiff: use git-compat-util
  test-prio-queue: use xmalloc

A test update.

* km/t3000-retitle:
  t3000 (ls-files -o): widen description to reflect current tests

An underallocation in the code to read the untracked cache
extension has been corrected.

* js/untracked-cache-allocfix:
  untracked cache: fix off-by-one

Test fix.

* js/t3301-unbreak-notes-test:
  t3301: fix false negative

Doc formatting fix.

* tz/doc-apostrophe-no-longer-needed:
  Documentation/git-show-branch: avoid literal {apostrophe}

"git blame -- path" in a non-bare repository starts blaming from
the working tree, and the same command in a bare repository errors
out because there is no working tree by definition.  The command
has been taught to instead start blaming from the commit at HEAD,
which is more useful.

* sg/blame-in-bare-start-at-head:
  blame: default to HEAD in a bare repo when no start commit is given

Debugging code fix.

* tg/ls-files-debug-format-fix:
  ls-files: use correct format string

Docfix.

* po/describe-not-necessarily-7:
  describe doc: remove '7-char' abbreviation reference

Docfix.

* po/rerere-doc-fmt:
  rerere doc: quote `rerere.enabled`

Updating the display with progress message has been cleaned up to
deal better with overlong messages.

* sg/overlong-progress-fix:
  progress: break too long progress bar lines
  progress: clear previous progress update dynamically
  progress: assemble percentage and counters in a strbuf before printing
  progress: make display_progress() return void

While running "git diff" in a lazy clone, we can upfront know which
missing blobs we will need, instead of waiting for the on-demand
machinery to discover them one by one.  Aim to achieve better
performance by batching the request for these promised blobs.

* jt/batch-fetch-blobs-in-diff:
  diff: batch fetching of missing blobs
  sha1-file: support OBJECT_INFO_FOR_PREFETCH

Update docs around "gc".

* ab/gc-docs:
  gc docs: remove incorrect reference to gc.auto=0
  gc docs: clarify that "gc" doesn't throw away referenced objects
  gc docs: note "gc --aggressive" in "fast-import"
  gc docs: downplay the usefulness of --aggressive
  gc docs: note how --aggressive impacts --window & --depth
  gc docs: fix formatting for "gc.writeCommitGraph"
  gc docs: re-flow the "gc.*" section in "config"
  gc docs: include the "gc.*" section from "config" in "gc"
  gc docs: clean grammar for "gc.bigPackThreshold"
  gc docs: stop noting "repack" flags
  gc docs: modernize the advice for manually running "gc"

"git submodule" learns "set-branch" subcommand that allows the
submodule.*.branch settings to be modified.

* dl/submodule-set-branch:
  submodule: teach set-branch subcommand
  submodule--helper: teach config subcommand --unset
  git-submodule.txt: "--branch <branch>" option defaults to 'master'

Performance fix for "rev-list --parents -- pathspec".

* jk/revision-rewritten-parents-in-prio-queue:
  revision: use a prio_queue to hold rewritten parents

Performance fix around "git blame", especially in a linear history
(which is the norm we should optimize for).

* dk/blame-keep-origin-blob:
  blame.c: don't drop origin blobs as eagerly

Conversion from unsigned char[20] to struct object_id continues.

* bc/hash-transition-16: (35 commits)
  gitweb: make hash size independent
  Git.pm: make hash size independent
  read-cache: read data in a hash-independent way
  dir: make untracked cache extension hash size independent
  builtin/difftool: use parse_oid_hex
  refspec: make hash size independent
  archive: convert struct archiver_args to object_id
  builtin/get-tar-commit-id: make hash size independent
  get-tar-commit-id: parse comment record
  hash: add a function to lookup hash algorithm by length
  remote-curl: make hash size independent
  http: replace sha1_to_hex
  http: compute hash of downloaded objects using the_hash_algo
  http: replace hard-coded constant with the_hash_algo
  http-walker: replace sha1_to_hex
  http-push: remove remaining uses of sha1_to_hex
  http-backend: allow 64-character hex names
  http-push: convert to use the_hash_algo
  builtin/pull: make hash-size independent
  builtin/am: make hash size independent
  ...

"git fast-import" update.

* en/fast-import-parsing-fix:
  fast-import: fix erroneous handling of get-mark with empty orphan commits
  fast-import: only allow cat-blob requests where it makes sense
  fast-import: check most prominent commands first
  git-fast-import.txt: fix wording about where ls command can appear
  t9300: demonstrate bug with get-mark and empty orphan commits

Fix for protocol v2 support in "git fetch-pack" of shallow clones.

* jt/fetch-no-update-shallow-in-proto-v2:
  fetch-pack: respect --no-update-shallow in v2
  fetch-pack: call prepare_shallow_info only if v0

Performance fix around "git fetch" that grabs many refs.

* jt/fetch-pack-wanted-refs-optim:
  fetch-pack: binary search when storing wanted-refs

Allow tracing of Git executable while running the testsuite.

* ab/test-lib-pass-trace2-env:
  test-lib: whitelist GIT_TR2_* in the environment

A progress indicator has been added to the "index-pack" step, which
often makes users wait for completion during "git clone".

* sg/index-pack-progress:
  index-pack: show progress while checking objects

Code cleanup with more careful error checking before using data
read from the commit-graph file.

* ab/commit-graph-fixes:
  commit-graph: improve & i18n error messages
  commit-graph write: don't die if the existing graph is corrupt
  commit-graph verify: detect inability to read the graph
  commit-graph: don't pass filename to load_commit_graph_one_fd_st()
  commit-graph: don't early exit(1) on e.g. "git status"
  commit-graph: fix segfault on e.g. "git status"
  commit-graph tests: test a graph that's too small
  commit-graph tests: split up corrupt_graph_and_verify()

Fix various glitches in "git gc" around reflog handling.

* ab/gc-reflog:
  gc: handle & check gc.reflogExpire config
  reflog tests: assert lack of early exit with expiry="never"
  reflog tests: test for the "points nowhere" warning
  reflog tests: make use of "test_config" idiom
  gc: refactor a "call me once" pattern
  gc: convert to using the_hash_algo
  gc: remove redundant check for gc_auto_threshold

"git checkout -m <other>" was about carrying the differences
between HEAD and the working-tree files forward while checking out
another branch, and ignored the differences between HEAD and the
index.  The command has been taught to abort when the index and the
HEAD are different.

* nd/checkout-m:
  checkout: prevent losing staged changes with --merge
  read-tree: add --quiet
  unpack-trees: rename "gently" flag to "quiet"
  unpack-trees: keep gently check inside add_rejected_path

"git difftool" can now run outside a repository.

* js/difftool-no-index:
  difftool: allow running outside Git worktrees with --no-index
  parse-options: make OPT_ARGUMENT() more useful
  difftool: remove obsolete (and misleading) comment

"git cherry-pick --options A..B", after giving control back to the
user to ask help resolving a conflicted step, did not honor the
options it originally received, which has been corrected.

* pw/cherry-pick-continue:
  cherry-pick --continue: remember options
  cherry-pick: demonstrate option amnesia
  sequencer: break some long lines

The message given when "git commit -a <paths>" errors out has been
updated.

* nd/commit-a-with-paths-msg-update:
  commit: improve error message in "-a <paths>" case

Code clean-up around a much-less-important-than-it-used-to-be
update_server_info() funtion.

* jk/server-info-rabbit-hole:
  update_info_refs(): drop unused force parameter
  server-info: drop objdirlen pointer arithmetic
  server-info: drop nr_alloc struct member
  server-info: use strbuf to read old info/packs file
  server-info: simplify cleanup in parse_pack_def()
  server-info: fix blind pointer arithmetic
  http: simplify parsing of remote objects/info/packs
  packfile: fix pack basename computation
  midx: check both pack and index names for containment
  t5319: drop useless --buffer from cat-file
  t5319: fix bogus cat-file argument
  pack-revindex: open index if necessary
  packfile.h: drop extern from function declarations