Code clean-up.

* jn/gc-auto-prep:
  gc: exit with status 128 on failure
  gc: improve handling of errors reading gc.log

Various test scripts have been updated for style and also correct
handling of exit status of various commands.

* md/test-cleanup:
  tests: order arguments to git-rev-list properly
  t9109: don't swallow Git errors upstream of pipes
  tests: don't swallow Git errors upstream of pipes
  t/*: fix ordering of expected/observed arguments
  tests: standardize pipe placement
  Documentation: add shell guidelines
  t/README: reformat Do, Don't, Keep in mind lists

Doc updates.

* fe/doc-updates:
  git-describe.1: clarify that "human readable" is also git-readable
  git-column.1: clarify initial description, provide examples
  git-archimport.1: specify what kind of Arch we're talking about

The mailmap file update.

* jn/mailmap-update:
  mailmap: consistently normalize brian m. carlson's name

Test update.

* tg/t5551-with-curl-7.61.1:
  t5551: compare sorted cookies files
  t5551: move setup code inside test_expect blocks

Code clean-up.

* en/merge-cleanup:
  merge-recursive: rename merge_file_1() and merge_content()
  merge-recursive: remove final remaining caller of merge_file_one()
  merge-recursive: avoid wrapper function when unnecessary and wasteful
  merge-recursive: set paths correctly when three-way merging content

Header files clean-up.

* rj/header-check:
  delta-islands.h: add missing forward declarations (hdr-check)
  midx.h: add missing forward declarations (hdr-check)
  refs/refs-internal.h: add missing declarations (hdr-check)
  refs/packed-backend.h: add missing declaration (hdr-check)
  refs/ref-cache.h: add missing declarations (hdr-check)
  ewah/ewok_rlw.h: add missing include (hdr-check)
  json-writer.h: add missing include (hdr-check)
  Makefile: add a hdr-check target

Doc update.

* ma/config-doc-update:
  git-config.txt: fix 'see: above' note
  Doc: use `--type=bool` instead of `--bool`

Fix interactions between two recent topics.

* jk/delta-islands-with-bitmap-reuse-delta-fix:
  pack-objects: handle island check for "external" delta base

Fix for typo in a sample code in comment.

* tq/refs-internal-comment-fix:
  refs: docstring typo

An alias that expands to another alias has so far been forbidden,
but now it is allowed to create such an alias.

* ts/alias-of-alias:
  t0014: introduce an alias testing suite
  alias: show the call history when an alias is looping
  alias: add support for aliases of an alias

The recently introduced commit-graph auxiliary data is incompatible
with mechanisms such as replace & grafts that "breaks" immutable
nature of the object reference relationship.  Disable optimizations
based on its use (and updating existing commit-graph) when these
incompatible features are in use in the repository.

* ds/commit-graph-with-grafts:
  commit-graph: close_commit_graph before shallow walk
  commit-graph: not compatible with uninitialized repo
  commit-graph: not compatible with grafts
  commit-graph: not compatible with replace objects
  test-repository: properly init repo
  commit-graph: update design document
  refs.c: upgrade for_each_replace_ref to be a each_repo_ref_fn callback
  refs.c: migrate internal ref iteration to pass thru repository argument

Generation of (experimental) commit-graph files have so far been
fairly silent, even though it takes noticeable amount of time in a
meaningfully large repository.  The users will now see progress
output.

* ab/commit-graph-progress:
  gc: fix regression in 7b0f2292 impacting --quiet
  commit-graph verify: add progress output
  commit-graph write: add progress output

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

Update fsck.skipList implementation and documentation.

* ab/fsck-skiplist:
  fsck: support comments & empty lines in skipList
  fsck: use oidset instead of oid_array for skipList
  fsck: use strbuf_getline() to read skiplist file
  fsck: add a performance test for skipList
  fsck: add a performance test
  fsck: document that skipList input must be unabbreviated
  fsck: document and test commented & empty line skipList input
  fsck: document and test sorted skipList input
  fsck tests: add a test for no skipList input
  fsck tests: setup of bogus commit object

"git multi-pack-index" learned to detect corruption in the .midx
file it uses, and this feature has been integrated into "git fsck".

* ds/multi-pack-verify:
  fsck: verify multi-pack-index
  multi-pack-index: report progress during 'verify'
  multi-pack-index: verify object offsets
  multi-pack-index: fix 32-bit vs 64-bit size check
  multi-pack-index: verify oid lookup order
  multi-pack-index: verify oid fanout order
  multi-pack-index: verify missing pack
  multi-pack-index: verify packname order
  multi-pack-index: verify corrupt chunk lookup table
  multi-pack-index: verify bad header
  multi-pack-index: add 'verify' verb

Various tests have been updated to make it easier to swap the
hash function used for object identification.

* bc/hash-independent-tests:
  t5318: use test_oid for HASH_LEN
  t1407: make hash size independent
  t1406: make hash-size independent
  t1405: make hash size independent
  t1400: switch hard-coded object ID to variable
  t1006: make hash size independent
  t0064: make hash size independent
  t0002: abstract away SHA-1 specific constants
  t0000: update tests for SHA-256
  t0000: use hash translation table
  t: add test functions to translate hash-related values

Test helper binaries clean-up.

* nd/test-tool:
  Makefile: add a hint about TEST_BUILTINS_OBJS
  t/helper: merge test-dump-fsmonitor into test-tool
  t/helper: merge test-parse-options into test-tool
  t/helper: merge test-pkt-line into test-tool
  t/helper: merge test-dump-untracked-cache into test-tool
  t/helper: keep test-tool command list sorted

Split Documentation/config.txt for easier maintenance.

* nd/config-split:
  config.txt: move submodule part out to a separate file
  config.txt: move sequence.editor out of "core" part
  config.txt: move sendemail part out to a separate file
  config.txt: move receive part out to a separate file
  config.txt: move push part out to a separate file
  config.txt: move pull part out to a separate file
  config.txt: move gui part out to a separate file
  config.txt: move gitcvs part out to a separate file
  config.txt: move format part out to a separate file
  config.txt: move fetch part out to a separate file
  config.txt: follow camelCase naming

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

It is a common mistake to put positional arguments before flags when
invoking git-rev-list. Order the positional arguments last.

This patch skips git-rev-list invocations which include the --not flag,
since the ordering of flags and positional arguments affects the
behavior. This patch also skips invocations of git-rev-list that occur
in command substitution in which the exit code is discarded, since
fixing those properly will require a more involved cleanup.
Signed-off-by: NMatthew DeVore <matvore@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

'git ... | foo' will mask any errors or crashes in git, so split up such
pipes in this file.

One testcase uses several separate pipe sequences in a row which are
awkward to split up. Wrap the split-up pipe in a function so the
awkwardness is not repeated. Also change that testcase's surrounding
quotes from double to single to avoid premature string interpolation.
Signed-off-by: NMatthew DeVore <matvore@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Some pipes in tests lose the exit code of git processes, which can mask
unexpected behavior like crashes. Split these pipes up so that git
commands are only at the end of pipes rather than the beginning or
middle.

The violations fixed in this patch were found in the process of fixing
pipe placement in a prior patch.
Signed-off-by: NMatthew DeVore <matvore@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Fix various places where the ordering was obviously wrong, meaning it
was easy to find with grep.
Signed-off-by: NMatthew DeVore <matvore@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Instead of using a line-continuation and pipe on the second line, take
advantage of the shell's implicit line continuation after a pipe
character.  So for example, instead of

	some long line \
		| next line

use

	some long line |
	next line

And add a blank line before and after the pipe where it aids readability
(it usually does).

This better matches the coding style documented in
Documentation/CodingGuidelines and used in shell scripts elsewhere in
the tree.
Signed-off-by: NMatthew DeVore <matvore@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Add the following guideline to Documentation/CodingGuidelines:

	Break overlong lines after "&&", "||", and "|", not before
	them; that way the command can continue to subsequent lines
	without backslash at the end.

And the following to t/README (since it is specific to writing tests):

	Pipes and $(git ...) should be avoided when they swallow exit
	codes of Git processes
Signed-off-by: NMatthew DeVore <matvore@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The list of Don'ts for test writing has grown large such that it is hard
to see at a glance which section an item is in. In other words, if I
ignore a little bit of surrounding context, the "don'ts" look like
"do's."

To make the list more readable, prefix "Don't" in front of every first
sentence in the items.

Also, the "Keep in mind" list is out of place and awkward, because it
was a very short "list" beneath two very long ones, and it seemed easy
to miss under the list of "don'ts," and it only had one item. So move
this item to the list of "do's" and phrase as "Remember..."
Signed-off-by: NMatthew DeVore <matvore@google.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

* maint:
  Git 2.19.1
  Git 2.18.1
  Git 2.17.2
  fsck: detect submodule paths starting with dash
  fsck: detect submodule urls starting with dash
  Git 2.16.5
  Git 2.15.3
  Git 2.14.5
  submodule-config: ban submodule paths that start with a dash
  submodule-config: ban submodule urls that start with dash
  submodule--helper: use "--" to signal end of clone options

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

* maint-2.18:
  Git 2.18.1
  Git 2.17.2
  fsck: detect submodule paths starting with dash
  fsck: detect submodule urls starting with dash
  Git 2.16.5
  Git 2.15.3
  Git 2.14.5
  submodule-config: ban submodule paths that start with a dash
  submodule-config: ban submodule urls that start with dash
  submodule--helper: use "--" to signal end of clone options

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

* maint-2.17:
  Git 2.17.2
  fsck: detect submodule paths starting with dash
  fsck: detect submodule urls starting with dash
  Git 2.16.5
  Git 2.15.3
  Git 2.14.5
  submodule-config: ban submodule paths that start with a dash
  submodule-config: ban submodule urls that start with dash
  submodule--helper: use "--" to signal end of clone options

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

As with urls, submodule paths with dashes are ignored by
git, but may end up confusing older versions. Detecting them
via fsck lets us prevent modern versions of git from being a
vector to spread broken .gitmodules to older versions.

Compared to blocking leading-dash urls, though, this
detection may be less of a good idea:

  1. While such paths provide confusing and broken results,
     they don't seem to actually work as option injections
     against anything except "cd". In particular, the
     submodule code seems to canonicalize to an absolute
     path before running "git clone" (so it passes
     /your/clone/-sub).

  2. It's more likely that we may one day make such names
     actually work correctly. Even after we revert this fsck
     check, it will continue to be a hassle until hosting
     servers are all updated.

On the other hand, it's not entirely clear that the behavior
in older versions is safe. And if we do want to eventually
allow this, we may end up doing so with a special syntax
anyway (e.g., writing "./-sub" in the .gitmodules file, and
teaching the submodule code to canonicalize it when
comparing).

So on balance, this is probably a good protection.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Urls with leading dashes can cause mischief on older
versions of Git. We should detect them so that they can be
rejected by receive.fsckObjects, preventing modern versions
of git from being a vector by which attacks can spread.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

* maint-2.16:
  Git 2.16.5
  Git 2.15.3
  Git 2.14.5
  submodule-config: ban submodule paths that start with a dash
  submodule-config: ban submodule urls that start with dash
  submodule--helper: use "--" to signal end of clone options

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

* maint-2.15:
  Git 2.15.3
  Git 2.14.5
  submodule-config: ban submodule paths that start with a dash
  submodule-config: ban submodule urls that start with dash
  submodule--helper: use "--" to signal end of clone options

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

* maint-2.14:
  Git 2.14.5
  submodule-config: ban submodule paths that start with a dash
  submodule-config: ban submodule urls that start with dash
  submodule--helper: use "--" to signal end of clone options