merge(third_party/git): Merge squashed git subtree at v2.23.0 r/373

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+git-for-each-ref(1)
+===================
+
+NAME
+----
+git-for-each-ref - Output information on each ref
+
+SYNOPSIS
+--------
+[verse]
+'git for-each-ref' [--count=<count>] [--shell|--perl|--python|--tcl]
+		   [(--sort=<key>)...] [--format=<format>] [<pattern>...]
+		   [--points-at=<object>]
+		   (--merged[=<object>] | --no-merged[=<object>])
+		   [--contains[=<object>]] [--no-contains[=<object>]]
+
+DESCRIPTION
+-----------
+
+Iterate over all refs that match `<pattern>` and show them
+according to the given `<format>`, after sorting them according
+to the given set of `<key>`.  If `<count>` is given, stop after
+showing that many refs.  The interpolated values in `<format>`
+can optionally be quoted as string literals in the specified
+host language allowing their direct evaluation in that language.
+
+OPTIONS
+-------
+<pattern>...::
+	If one or more patterns are given, only refs are shown that
+	match against at least one pattern, either using fnmatch(3) or
+	literally, in the latter case matching completely or from the
+	beginning up to a slash.
+
+--count=<count>::
+	By default the command shows all refs that match
+	`<pattern>`.  This option makes it stop after showing
+	that many refs.
+
+--sort=<key>::
+	A field name to sort on.  Prefix `-` to sort in
+	descending order of the value.  When unspecified,
+	`refname` is used.  You may use the --sort=<key> option
+	multiple times, in which case the last key becomes the primary
+	key.
+
+--format=<format>::
+	A string that interpolates `%(fieldname)` from a ref being shown
+	and the object it points at.  If `fieldname`
+	is prefixed with an asterisk (`*`) and the ref points
+	at a tag object, use the value for the field in the object
+	which the tag object refers to (instead of the field in the tag object).
+	When unspecified, `<format>` defaults to
+	`%(objectname) SPC %(objecttype) TAB %(refname)`.
+	It also interpolates `%%` to `%`, and `%xx` where `xx`
+	are hex digits interpolates to character with hex code
+	`xx`; for example `%00` interpolates to `\0` (NUL),
+	`%09` to `\t` (TAB) and `%0a` to `\n` (LF).
+
+--color[=<when>]::
+	Respect any colors specified in the `--format` option. The
+	`<when>` field must be one of `always`, `never`, or `auto` (if
+	`<when>` is absent, behave as if `always` was given).
+
+--shell::
+--perl::
+--python::
+--tcl::
+	If given, strings that substitute `%(fieldname)`
+	placeholders are quoted as string literals suitable for
+	the specified host language.  This is meant to produce
+	a scriptlet that can directly be `eval`ed.
+
+--points-at=<object>::
+	Only list refs which points at the given object.
+
+--merged[=<object>]::
+	Only list refs whose tips are reachable from the
+	specified commit (HEAD if not specified),
+	incompatible with `--no-merged`.
+
+--no-merged[=<object>]::
+	Only list refs whose tips are not reachable from the
+	specified commit (HEAD if not specified),
+	incompatible with `--merged`.
+
+--contains[=<object>]::
+	Only list refs which contain the specified commit (HEAD if not
+	specified).
+
+--no-contains[=<object>]::
+	Only list refs which don't contain the specified commit (HEAD
+	if not specified).
+
+--ignore-case::
+	Sorting and filtering refs are case insensitive.
+
+FIELD NAMES
+-----------
+
+Various values from structured fields in referenced objects can
+be used to interpolate into the resulting output, or as sort
+keys.
+
+For all objects, the following names can be used:
+
+refname::
+	The name of the ref (the part after $GIT_DIR/).
+	For a non-ambiguous short name of the ref append `:short`.
+	The option core.warnAmbiguousRefs is used to select the strict
+	abbreviation mode. If `lstrip=<N>` (`rstrip=<N>`) is appended, strips `<N>`
+	slash-separated path components from the front (back) of the refname
+	(e.g. `%(refname:lstrip=2)` turns `refs/tags/foo` into `foo` and
+	`%(refname:rstrip=2)` turns `refs/tags/foo` into `refs`).
+	If `<N>` is a negative number, strip as many path components as
+	necessary from the specified end to leave `-<N>` path components
+	(e.g. `%(refname:lstrip=-2)` turns
+	`refs/tags/foo` into `tags/foo` and `%(refname:rstrip=-1)`
+	turns `refs/tags/foo` into `refs`). When the ref does not have
+	enough components, the result becomes an empty string if
+	stripping with positive <N>, or it becomes the full refname if
+	stripping with negative <N>.  Neither is an error.
++
+`strip` can be used as a synonym to `lstrip`.
+
+objecttype::
+	The type of the object (`blob`, `tree`, `commit`, `tag`).
+
+objectsize::
+	The size of the object (the same as 'git cat-file -s' reports).
+	Append `:disk` to get the size, in bytes, that the object takes up on
+	disk. See the note about on-disk sizes in the `CAVEATS` section below.
+objectname::
+	The object name (aka SHA-1).
+	For a non-ambiguous abbreviation of the object name append `:short`.
+	For an abbreviation of the object name with desired length append
+	`:short=<length>`, where the minimum length is MINIMUM_ABBREV. The
+	length may be exceeded to ensure unique object names.
+deltabase::
+	This expands to the object name of the delta base for the
+	given object, if it is stored as a delta.  Otherwise it
+	expands to the null object name (all zeroes).
+
+upstream::
+	The name of a local ref which can be considered ``upstream''
+	from the displayed ref. Respects `:short`, `:lstrip` and
+	`:rstrip` in the same way as `refname` above.  Additionally
+	respects `:track` to show "[ahead N, behind M]" and
+	`:trackshort` to show the terse version: ">" (ahead), "<"
+	(behind), "<>" (ahead and behind), or "=" (in sync). `:track`
+	also prints "[gone]" whenever unknown upstream ref is
+	encountered. Append `:track,nobracket` to show tracking
+	information without brackets (i.e "ahead N, behind M").
++
+For any remote-tracking branch `%(upstream)`, `%(upstream:remotename)`
+and `%(upstream:remoteref)` refer to the name of the remote and the
+name of the tracked remote ref, respectively. In other words, the
+remote-tracking branch can be updated explicitly and individually by
+using the refspec `%(upstream:remoteref):%(upstream)` to fetch from
+`%(upstream:remotename)`.
++
+Has no effect if the ref does not have tracking information associated
+with it.  All the options apart from `nobracket` are mutually exclusive,
+but if used together the last option is selected.
+
+push::
+	The name of a local ref which represents the `@{push}`
+	location for the displayed ref. Respects `:short`, `:lstrip`,
+	`:rstrip`, `:track`, `:trackshort`, `:remotename`, and `:remoteref`
+	options as `upstream` does. Produces an empty string if no `@{push}`
+	ref is configured.
+
+HEAD::
+	'*' if HEAD matches current ref (the checked out branch), ' '
+	otherwise.
+
+color::
+	Change output color. Followed by `:<colorname>`, where color
+	names are described under Values in the "CONFIGURATION FILE"
+	section of linkgit:git-config[1].  For example,
+	`%(color:bold red)`.
+
+align::
+	Left-, middle-, or right-align the content between
+	%(align:...) and %(end). The "align:" is followed by
+	`width=<width>` and `position=<position>` in any order
+	separated by a comma, where the `<position>` is either left,
+	right or middle, default being left and `<width>` is the total
+	length of the content with alignment. For brevity, the
+	"width=" and/or "position=" prefixes may be omitted, and bare
+	<width> and <position> used instead.  For instance,
+	`%(align:<width>,<position>)`. If the contents length is more
+	than the width then no alignment is performed. If used with
+	`--quote` everything in between %(align:...) and %(end) is
+	quoted, but if nested then only the topmost level performs
+	quoting.
+
+if::
+	Used as %(if)...%(then)...%(end) or
+	%(if)...%(then)...%(else)...%(end).  If there is an atom with
+	value or string literal after the %(if) then everything after
+	the %(then) is printed, else if the %(else) atom is used, then
+	everything after %(else) is printed. We ignore space when
+	evaluating the string before %(then), this is useful when we
+	use the %(HEAD) atom which prints either "*" or " " and we
+	want to apply the 'if' condition only on the 'HEAD' ref.
+	Append ":equals=<string>" or ":notequals=<string>" to compare
+	the value between the %(if:...) and %(then) atoms with the
+	given string.
+
+symref::
+	The ref which the given symbolic ref refers to. If not a
+	symbolic ref, nothing is printed. Respects the `:short`,
+	`:lstrip` and `:rstrip` options in the same way as `refname`
+	above.
+
+worktreepath::
+	The absolute path to the worktree in which the ref is checked
+	out, if it is checked out in any linked worktree. Empty string
+	otherwise.
+
+In addition to the above, for commit and tag objects, the header
+field names (`tree`, `parent`, `object`, `type`, and `tag`) can
+be used to specify the value in the header field.
+
+For commit and tag objects, the special `creatordate` and `creator`
+fields will correspond to the appropriate date or name-email-date tuple
+from the `committer` or `tagger` fields depending on the object type.
+These are intended for working on a mix of annotated and lightweight tags.
+
+Fields that have name-email-date tuple as its value (`author`,
+`committer`, and `tagger`) can be suffixed with `name`, `email`,
+and `date` to extract the named component.
+
+The complete message in a commit and tag object is `contents`.
+Its first line is `contents:subject`, where subject is the concatenation
+of all lines of the commit message up to the first blank line.  The next
+line is `contents:body`, where body is all of the lines after the first
+blank line.  The optional GPG signature is `contents:signature`.  The
+first `N` lines of the message is obtained using `contents:lines=N`.
+Additionally, the trailers as interpreted by linkgit:git-interpret-trailers[1]
+are obtained as `trailers` (or by using the historical alias
+`contents:trailers`).  Non-trailer lines from the trailer block can be omitted
+with `trailers:only`. Whitespace-continuations can be removed from trailers so
+that each trailer appears on a line by itself with its full content with
+`trailers:unfold`. Both can be used together as `trailers:unfold,only`.
+
+For sorting purposes, fields with numeric values sort in numeric order
+(`objectsize`, `authordate`, `committerdate`, `creatordate`, `taggerdate`).
+All other fields are used to sort in their byte-value order.
+
+There is also an option to sort by versions, this can be done by using
+the fieldname `version:refname` or its alias `v:refname`.
+
+In any case, a field name that refers to a field inapplicable to
+the object referred by the ref does not cause an error.  It
+returns an empty string instead.
+
+As a special case for the date-type fields, you may specify a format for
+the date by adding `:` followed by date format name (see the
+values the `--date` option to linkgit:git-rev-list[1] takes).
+
+Some atoms like %(align) and %(if) always require a matching %(end).
+We call them "opening atoms" and sometimes denote them as %($open).
+
+When a scripting language specific quoting is in effect, everything
+between a top-level opening atom and its matching %(end) is evaluated
+according to the semantics of the opening atom and only its result
+from the top-level is quoted.
+
+
+EXAMPLES
+--------
+
+An example directly producing formatted text.  Show the most recent
+3 tagged commits:
+
+------------
+#!/bin/sh
+
+git for-each-ref --count=3 --sort='-*authordate' \
+--format='From: %(*authorname) %(*authoremail)
+Subject: %(*subject)
+Date: %(*authordate)
+Ref: %(*refname)
+
+%(*body)
+' 'refs/tags'
+------------
+
+
+A simple example showing the use of shell eval on the output,
+demonstrating the use of --shell.  List the prefixes of all heads:
+------------
+#!/bin/sh
+
+git for-each-ref --shell --format="ref=%(refname)" refs/heads | \
+while read entry
+do
+	eval "$entry"
+	echo `dirname $ref`
+done
+------------
+
+
+A bit more elaborate report on tags, demonstrating that the format
+may be an entire script:
+------------
+#!/bin/sh
+
+fmt='
+	r=%(refname)
+	t=%(*objecttype)
+	T=${r#refs/tags/}
+
+	o=%(*objectname)
+	n=%(*authorname)
+	e=%(*authoremail)
+	s=%(*subject)
+	d=%(*authordate)
+	b=%(*body)
+
+	kind=Tag
+	if test "z$t" = z
+	then
+		# could be a lightweight tag
+		t=%(objecttype)
+		kind="Lightweight tag"
+		o=%(objectname)
+		n=%(authorname)
+		e=%(authoremail)
+		s=%(subject)
+		d=%(authordate)
+		b=%(body)
+	fi
+	echo "$kind $T points at a $t object $o"
+	if test "z$t" = zcommit
+	then
+		echo "The commit was authored by $n $e
+at $d, and titled
+
+    $s
+
+Its message reads as:
+"
+		echo "$b" | sed -e "s/^/    /"
+		echo
+	fi
+'
+
+eval=`git for-each-ref --shell --format="$fmt" \
+	--sort='*objecttype' \
+	--sort=-taggerdate \
+	refs/tags`
+eval "$eval"
+------------
+
+
+An example to show the usage of %(if)...%(then)...%(else)...%(end).
+This prefixes the current branch with a star.
+
+------------
+git for-each-ref --format="%(if)%(HEAD)%(then)* %(else)  %(end)%(refname:short)" refs/heads/
+------------
+
+
+An example to show the usage of %(if)...%(then)...%(end).
+This prints the authorname, if present.
+
+------------
+git for-each-ref --format="%(refname)%(if)%(authorname)%(then) Authored by: %(authorname)%(end)"
+------------
+
+CAVEATS
+-------
+
+Note that the sizes of objects on disk are reported accurately, but care
+should be taken in drawing conclusions about which refs or objects are
+responsible for disk usage. The size of a packed non-delta object may be
+much larger than the size of objects which delta against it, but the
+choice of which object is the base and which is the delta is arbitrary
+and is subject to change during a repack.
+
+Note also that multiple copies of an object may be present in the object
+database; in this case, it is undefined which copy's size or delta base
+will be reported.
+
+SEE ALSO
+--------
+linkgit:git-show-ref[1]
+
+GIT
+---
+Part of the linkgit:git[1] suite