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

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

* nd/diff-parseopt-4:
  am: avoid diff_opt_parse()
  diff --no-index: use parse_options() instead of diff_opt_parse()
  range-diff: use parse_options() instead of diff_opt_parse()
  diff.c: allow --no-color-moved-ws
  diff-parseopt: convert --color-moved-ws
  diff-parseopt: convert --[no-]color-moved
  diff-parseopt: convert --inter-hunk-context
  diff-parseopt: convert --no-prefix
  diff-parseopt: convert --line-prefix
  diff-parseopt: convert --[src|dst]-prefix
  diff-parseopt: convert --[no-]abbrev
  diff-parseopt: convert --diff-filter
  diff-parseopt: convert --find-object
  diff-parseopt: convert -O
  diff-parseopt: convert --pickaxe-all|--pickaxe-regex
  diff-parseopt: convert -S|-G
  diff-parseopt: convert -l
  diff-parseopt: convert -z
  diff-parseopt: convert --ita-[in]visible-in-index
  diff-parseopt: convert --ws-error-highlight

Code cleanup.

* jk/unused-params-even-more:
  parse_opt_ref_sorting: always use with NONEG flag
  pretty: drop unused strbuf from parse_padding_placeholder()
  pretty: drop unused "type" parameter in needs_rfc2047_encoding()
  parse-options: drop unused ctx parameter from show_gitcomp()
  fetch_pack(): drop unused parameters
  report_path_error(): drop unused prefix parameter
  unpack-trees: drop unused error_type parameters
  unpack-trees: drop name_entry from traverse_by_cache_tree()
  test-date: drop unused "now" parameter from parse_dates()
  update-index: drop unused prefix_length parameter from do_reupdate()
  log: drop unused "len" from show_tagger()
  log: drop unused rev_info from early output
  revision: drop some unused "revs" parameters

Test framework update to more robustly clean up leftover files and
processes after tests are done.

* sg/test-atexit:
  t9811-git-p4-label-import: fix pipeline negation
  git p4 test: disable '-x' tracing in the p4d watchdog loop
  git p4 test: simplify timeout handling
  git p4 test: clean up the p4d cleanup functions
  git p4 test: use 'test_atexit' to kill p4d and the watchdog process
  t0301-credential-cache: use 'test_atexit' to stop the credentials helper
  tests: use 'test_atexit' to stop httpd
  git-daemon: use 'test_atexit` to stop 'git-daemon'
  test-lib: introduce 'test_atexit'
  t/lib-git-daemon: make sure to kill the 'git-daemon' process
  test-lib: fix interrupt handling with 'dash' and '--verbose-log -x'

The scripted version of "git rebase -i" wrote and rewrote the todo
list many times during a single step of its operation, and the
recent C-rewrite made a faithful conversion of the logic to C.  The
implementation has been updated to carry necessary information
around in-core to avoid rewriting the same file over and over
unnecessarily.

* ag/sequencer-reduce-rewriting-todo:
  rebase--interactive: move transform_todo_file()
  sequencer: use edit_todo_list() in complete_action()
  rebase-interactive: rewrite edit_todo_list() to handle the initial edit
  rebase-interactive: append_todo_help() changes
  rebase-interactive: use todo_list_write_to_file() in edit_todo_list()
  sequencer: refactor skip_unnecessary_picks() to work on a todo_list
  rebase--interactive: move rearrange_squash_in_todo_file()
  rebase--interactive: move sequencer_add_exec_commands()
  sequencer: change complete_action() to use the refactored functions
  sequencer: make sequencer_make_script() write its script to a strbuf
  sequencer: refactor rearrange_squash() to work on a todo_list
  sequencer: refactor sequencer_add_exec_commands() to work on a todo_list
  sequencer: refactor check_todo_list() to work on a todo_list
  sequencer: introduce todo_list_write_to_file()
  sequencer: refactor transform_todos() to work on a todo_list
  sequencer: remove the 'arg' field from todo_item
  sequencer: make the todo_list structure public
  sequencer: changes in parse_insn_buffer()

A new hook "post-index-change" is called when the on-disk index
file changes, which can help e.g. a virtualized working tree
implementation.

* bp/post-index-change-hook:
  read-cache: add post-index-change hook

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

"git mergetool" learned to offer Sublime Merge (smerge) as one of
its backends.

* da/smerge:
  contrib/completion: add smerge to the mergetool completion candidates
  mergetools: add support for smerge (Sublime Merge)

Code clean-up.

* dl/flex-str-cocci:
  cocci: FLEX_ALLOC_MEM to FLEX_ALLOC_STR
  midx.c: convert FLEX_ALLOC_MEM to FLEX_ALLOC_STR

The tests have been updated not to rely on the abbreviated option
names the parse-options API offers, to protect us from an
abbreviated form of an option that used to be unique within the
command getting non-unique when a new option that share the same
prefix is added.

* js/spell-out-options-in-tests:
  tests: disallow the use of abbreviated options (by default)
  tests (pack-objects): use the full, unabbreviated `--revs` option
  tests (status): spell out the `--find-renames` option in full
  tests (push): do not abbreviate the `--follow-tags` option
  t5531: avoid using an abbreviated option
  t7810: do not abbreviate `--no-exclude-standard` nor `--invert-match`
  tests (rebase): spell out the `--force-rebase` option
  tests (rebase): spell out the `--keep-empty` option

The documentation for "git read-tree --reset -u" has been updated.

* nd/read-tree-reset-doc:
  read-tree.txt: clarify --reset and worktree changes

Doc update.

* nd/interpret-trailers-docfix:
  interpret-trailers.txt: start the desc line with a capital letter

Update our support to format documentation in the CI environment,
either with AsciiDoc ro Asciidoctor.

* sg/asciidoctor-in-ci:
  ci: fix AsciiDoc/Asciidoctor stderr check in the documentation build job
  ci: stick with Asciidoctor v1.5.8 for now
  ci: install Asciidoctor in 'ci/install-dependencies.sh'
  Documentation/technical/protocol-v2.txt: fix formatting
  Documentation/technical/api-config.txt: fix formatting
  Documentation/git-diff-tree.txt: fix formatting

Doc updates.

* tz/asciidoctor-fixes:
  Documentation/git-status: fix titles in porcelain v2 section
  Documentation/rev-list-options: wrap --date=<format> block with "--"

Dev support update.

* js/check-docs-exe:
  check-docs: fix for setups where executables have an extension
  check-docs: do not expect guide pages to correspond to commands
  check-docs: really look at the documented commands again
  docs: do not document the `git remote-testgit` command
  docs: move gitremote-helpers into section 7

A buglet in configuration parser has been fixed.

* nd/include-if-wildmatch:
  config: correct '**' matching in includeIf patterns

Clean-up markup in the documentation suite.

* cb/doco-mono:
  doc: format pathnames and URLs as monospace.
  doc/CodingGuidelines: URLs and paths as monospace

A regression fix.

* tg/stash-in-c-show-default-to-p-fix:
  stash: setup default diff output format if necessary

Further fixes to "git stash" reimplemented in C.

* js/stash-in-c-pathspec-fix:
  stash: pass pathspec as pointer
  built-in stash: handle :(glob) pathspecs again
  legacy stash: fix "rudimentary backport of -q"

Code clean-up.

* tb/stash-in-c-unused-param-fix:
  stash: drop unused parameter

"git stash" rewritten in C.

* ps/stash-in-c: (28 commits)
  tests: add a special setup where stash.useBuiltin is off
  stash: optionally use the scripted version again
  stash: add back the original, scripted `git stash`
  stash: convert `stash--helper.c` into `stash.c`
  stash: replace all `write-tree` child processes with API calls
  stash: optimize `get_untracked_files()` and `check_changes()`
  stash: convert save to builtin
  stash: make push -q quiet
  stash: convert push to builtin
  stash: convert create to builtin
  stash: convert store to builtin
  stash: convert show to builtin
  stash: convert list to builtin
  stash: convert pop to builtin
  stash: convert branch to builtin
  stash: convert drop and clear to builtin
  stash: convert apply to builtin
  stash: mention options in `show` synopsis
  stash: add tests for `git stash show` config
  stash: rename test cases to be more descriptive
  ...

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

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